Hi John, Great video, I noticed a typo in the 4:30 writing : the imperial to metric is inverted. 82lb is 37kg and 92lb is 42kg. I hope it's not too late to correct.
I completely agree. Frank was a wonderful person who helped us all by sharing his experience and discoveries as a brilliant guitar whisperer. Any reader unfamiliar with his work should check out Frets.com
Hello Mr. Parker, First of all, I apologize for the length of this comment. I am very thankful to you for making the Archtoppery series. I have been watching all of the videos for several years now, and it’s not only fascinating, but I find it cathartic to watch along (particularly on the longer form videos) as you transform these materials into functional works of art. I am a fan of archtops, and I own several Gibsons and Epiphones from the 30s. If I could ever commission a guitar from you, that would be a dream come true. I became interested in your work about 3 years ago when I acquired a 1994 Galaxy Gray hardtail Fly in a massive trade I did with a (now) friend. He told me that he purchased it directly from you in Rochester in 2004 when you were getting out of the solid guitar phase. He also said that it was a special order that the customer never paid for, and you held onto since 1994. Whether or not that is accurate is somewhat irrelevant to me, but if it’s true, I think it would be cool. I had never touched a Fly before, but I was aware of their existence. Upon becoming the new owner of the instrument, I very quickly became somewhat obsessed with learning as much about you and your instruments as possible, as among the 100 or so guitars I’ve owned in my time, I’d never experienced anything like the Fly. Let’s just say that it impresses me from an engineering perspective more so than any other instrument that I’ve ever touched. It plays so well that it almost feels like cheating. I’ve joined various forums and scoured the internet to find out as much about you as possible, and I’ve learned quite a lot from you thus far. In my book, you are a truly inventive pioneer like Antonio Torres, Loyd Loar, Les Paul, Leo Fender, etc., but you are also able to create instruments with the beauty and elegance equal to Antonio Stradivari. I look forward to anything new that you want to share. Again, thank you.
Wow, what a wonderful letter. Thanks for your extravagant praise! Here's a comment that I'll be sure to show my wife! I can't tell you how much I love my job. What a privilege to have found it as a young punk. I was just another lost 20 year old to whom the world of business and the goal of material acquisition just looked empty and dull to me. When I saw someone expertly use a hand plane to take gossamer shavings of a black walnut plank. It looked like a magic trick to me, and I never looked back. Still rainin', still dreamin'.
Thanks for your enthusiasm! I guess I don't think of myself as breaking from tradition, which, it turns out, is a continuum. I think that all of us contemporary builders are adding to the time line, and thereby a part of the tradition of improving designs to suit the needs of contemporary musicians. I have always been fascinated by the accomplishments of my predecessors, and especially by their expert and efficient hand tool use before electric motors changed craftsmanship forever. Usually when folks are asked what guitars they consider traditional, they cite ones that they admire most. Often these are ones they wish they could afford that were built before they were born. Tradition is in the eye of the beholder! One of my favorite traditional instruments is a hollow log and a couple of sticks.
Ya know…it’s really crazy…I ran into a young man in the desert of California…and he was playing one of your acoustics…I had a friend of mine with me, who is a musician and they had an impromptu jam back and forth on the side of the road… You make some amazing guitars man….
Simple trust rod like Gibson or even Fender one is a perfect design ... I agree. You said what I'm thinking for many years now!! M Parker, you are my hero!!
Ken. I look forward to all your videos. Always a refreshing re-think on what are sometimes dogmatic beliefs in lutherie. This one is no exception. I totally misunderstood the single true rod. I assumed that it was set in the neck on a curve. (The ends being up and the middle pressed down into the pocket by a wood plug?) .and that when tention is applied, it wants to straighten. Kind of like how an archtop bridge applies the vertical vector of the string load to the top based on the break angle. The whole time, it was just tention. 🙄
People do use rods like that. Not really viable on thin current necks, because if you use a lot of curvature, the strip of wood in the middle becomes too thin, or you cross over the neutral plane, which robs you from all your mechanical gains. Double action rods are better, in my opinion. Not because they can act both ways, but because they can apply a lot of balancing force without big compressive loads, which wood does not like.
This can be confusing, and I suppose you could think of it either way, but I suspect that we're not arguing that the steel rod is loaded in tension when the truss rod is tightened, and thereby induces a compressive load on the wood in the neck. If this simple nut and bolt is located properly within the neck, this action will shorten the back of the neck considerably more than the fingerboard side of the neck, counter-acting the compressive load applied by the strings, thereby straightening the curve that the strings induce.
I wonder.. Wouldn't you need a two-way trussrod in order to acieve the needed relieve with this super stiff neck construction? I sometimes install a truss for my nylons because the tension isn't enought to get enought back bend. Thanks for sharing 🙏
I'll go into the details of my neck plan, and the nuts and bolts of how I anticipate and allow for the string's forces in real time pretty soon. Guessing, I have discovered, is a mistake, as you mention. Measuring under load is key.
Hey Ken Well done as usual interesting as im about to install a D -Tune into the same type Epiphone archtop as you are describing i was trying to find your # to chat about it as this is a new process for me and want to make sure of success Your description has given me confidence to move forward. In case u your wondering who the hell this is its Peter Meyer who use to do repair at Diamond Cove Music .i now happily work from my basement in Maine .These vids you are doing are a great contribution to the art so thanks!!
Call me, Peter, if you haven't done this yet. I still have the big poplar fixture I built to hold the guitar, and would be delighted to let you use it. Glad you're digging the series!
A wider flatter dual action truss rod just under the fingerboard might allow for a thinner neck. Solid bars on either side of the adjustable rod, instead of a solid bar underneath it. The geometry would have to be designed so it still bends up and down, not sideways in some manner. OTOH, I'm able to re-carve a stock dual-action truss rod neck down to 20mm thick without issues - and 20mm is probably thin enough from a player's perspective. You're right about the weight savings with carbon fiber reinforcement. The carbon fiber tube necks I made were insanely light - especially the triple tube neck.
Great information Ken. I would have to agree on the hotrod/dual action rods. They aren't a very efficient design. PRS sorted out a pretty cool solution for dual action without the additional steel bar. Unfortunately, it seems the need for dual action adjustment can be solely blamed on poor materials and/or the drying process. I spent a portion of my education in the architectural engineering school before focusing on architecture... Your analysis of cantilevered beam action is spot on... Side note... I was at a guitar show in Colorado today. A few folks mentioned you were at the arch-top show last fall in Arvada and I missed it! I'll be at the show this year for sure... It will be fun to see everything that is happening in the building community.
He obviously did not go into the gory details. First of all, in order to counteract the compression of the strings, the classic rod needs to also be a compressive force. Which means, that all the material of the neck is being compressed. Wood isn't that great when it comes to compression. Sooner or later it will crush, likely the maple, which is softer. Then, there is a problem of leverage. Since the strings are much further away from the neutral plane, in order to balance them out we need to apply significantly more force through the rod. 3 or 4 times more? Thereabouts. No wonder people break the threads at times. The double action rod only gently helps. The fretboard still is under compression, the maple still under tension, where it "likes" to be, and the rod is there to only apply a very small balancing force. Yes, it's heavier. Yes, it's more expensive. I still prefer it.
Looking forward to meeting you in Arvada! We agree. A good neck that stays put is achievable by we mortals, but you've got to do it skillfully, and use good, properly dried materials. I wonder if PRS patented their truss rod? If so, then there is a public record including good drawings in the US Patent database. After all, the trade-off for getting protection for your invention (if it IS an invention and is issued a defensible US utility Patent) is that you must describe it in enough detail so that others "skilled in the art" of your field can read your patent and discover exactly what you've invented. Amusingly, due to this and that, patents are commonly issued in error, which might only be discovered if there was a serious legal battle over rights. You can't patent an idea that was common practice in your field centuries ago and expect to defend it in court! Examples in our corner of the world include Buzzy Feiten's and Ralph Novak's patents on moving the frets and the nut around the fingerboard.
@@kenparkerarchtoppery9440 I can't remember if Paul patented that one. It's just a thin rod (3/16"?) with a right handed thread on one end and a lefty on the other. Works just like a turnbuckle... I did look up his list of patents one day and was surprised at how many medical devices he holds patents on... Apparently the guy knows a lot about wave theory - go figure!
You bring up important things, but I'll push back on your assertion about wood's poor compressional strength and refer you to multi-story post and beam buildings, along with the engineering analysis showing that chair legs could be sized at 1/8" or 3mm diameter from many species, and be fully capable of doing their jobs properly as legs if they could be kept in column. in 15 years of experience as a repairman, I believe that broken rods are almost always the result of being hilariously/disastrously over-tightened, either due to: 1) The misunderstanding of their function and abilities 2) Lack of lubricant 3) Ethanol or other mind-altering substances' effects on the good judgement of frustrated guitar owners 4) Misguided exploratory efforts to "See what the rod can do", likely combined with one or more of the first three. In all my days, having adjusted quite literally thousands of truss rods, I have never broken one, and really can't conceive of doing so. A person with any kind of what we call "mechanic's feel" will stop well short of applying the forces necessary to shear off a properly designed and manufactured steel truss rod of the Gibson/Fender type. 30+ years ago, my lathe and I made a sneaky set of cutters and threading tools designed to repair broken off rods in Gibsons and Fenders, and with them have been able to restore the function of any broken rods that I was presented with. I believe that one can now buy such things at Stu-Mac. A useful tip is to wet the wood under the washer with thin CA, where it will wick deeply down into the cellular tubes reinforcing this highly loaded surface. Add weight if you feel it's good practice, but I don't feel it's necessary, as it works against good balance, in most designs.
@@kenparkerarchtoppery9440 This has gone in an interesting direction. I agree, wood in a solely axial load is VERY strong. Off axis loading can cause the crushing of fibers @bakters mentions. My question is - how would that happen in a guitar neck? Most guitar necks experience very little dynamic force over their lifetimes. I would offer that a neck's loading is 99.9% static (I'm not going to count the wave action caused by playing). The dynamic loads that would potentially cause failure are: over tightening the truss rod, wood movement, the artist pushing on the neck to bend a note (common with some players), and maybe string changes. I have seen broken truss rods in my repairs. I haven't been the culprit, I've been the fixer. They were ALL due to two factors: 1) corrosion due to poor storage conditions (or a spill of some kind), 2) gauling or cross-threading. I don't know how people do it, but I've seen several truss rods with mushroomed and/or smashed threads. Are people hitting them with hammers? All this said, I wonder if simply stiffening the end grain where the truss rod bears is a way to improve how it seats thus mitigating the few dynamic loads??? As for my money - I like the light weight rods I make with drill rod and a welded slug at the treble end of the neck. Simple, cheap and effective! :D
As always, thank you. What do you think of PRS truss rod design? If i'm not mistaken, its dual action truss rod using the front of the neck and the fretboard as the "non moving" part of the truss rod. 1 rod, dual action.
This is something I was made aware of only recently by another commentator. I respect Paul very much, and am not surprised that he or someone in his company came up with a novel 2 way single rod, Bravo! I never felt the need for an adjuster that worked in such a way in my own work. My experience showed me that a carefully built neck of premium materials was perfectly well served by the original, close-to-the-back-of-the-neck rod designed to counteract the string's forces. Over the years I have seen other embodiments claiming this 2 way thing, and although I don't see the need for it, it's nice to have it in your back pocket just in case. Kudos, and please explain to us how this one works if you can.
@@kenparkerarchtoppery9440 The principle is very simple, imagine a rod threaded at each extremities, one thread is left, the other right (not sure it's appropriately said). Well lets say 1 side threaded an the other counterthreaded. 2 little plates are "screwed" on these threads which is then embeded in the neck itself. the plates, a little larger than the rod, are inserted in grooves and are blocked in place. now, when you turn the rod clockwise, it tends to get the plates closer, counterclockwise to have them go away forme one another. I hope it's clearly explained ;)
@kenparkerarchtoppery9440 Is it necessary to have a truss rod that can remove both back bow and forward bow? Or is being able to remove forward bow sufficient? I note that Ebony has a very high rate of longitudinal shrink/expansion with humidity, much higher than the species used for the shaft of the neck. It seems to me that this difference could bow the neck in either direction as humidity changes from that in which the two species were glued together.
Good points. I think that two-way rods are rarely needed, and can add complexity. If the neck is built in a "normal" way, it shouldn't need adjustment in the "other" direction. There are rare exceptions, but, in my view, not enough to justify the added complexity and added weight. Having said this, it was brought to attention that PRS guitars have a 2 way rod that is also a single rod, but I confess to having zero knowledge of these, partly because I quit repairing guitars before they came out. If anyone can explain their rod or share their experiences with them, I'd be curious to hear it. On the long axis mis-behavior of ebony, I guess I'm not aware that it is a real thing in real life, as I've experienced it, although sometimes there can be a shrinkage problem across the grain on maple necks. Ebony varies widely, apart from the fact that there are several species marketed as Ebony, and these things make it hard to come to good conclusions about our wonderful friend Ebony.
@@kenparkerarchtoppery9440 Yeah, I don't know if Ebony is a problem from personal experience, I've just seen other luthiers say they've had problem with it bowing the neck under humidity changes. The longitudinal shrink rate for Gaboon Ebony seems to be about 1.26% (green to ovendry). This is calculated from the radial, tangential, and volumetric numbers on wood-database. Honduran Mahogany would be 0.46%, and Douglas fir 0.15%. Maybe that's just not enough of a difference to cause significant bowing.
Thanks Ken! So, does a single action rod always require a curved channel? Also, how do you feel about the U-channel 2-way type without the 2nd rod like the low profile hot rod?
As I mentioned somewhere on the site, the rod can be curved the "right" way, the "wrong" way, or dead straight, and all of these designs will work OK as long as the attachment points are some distance from the neutral plane in order that the rod acts like it's a nice strong string on the "other side" of the neck, so as to counterbalance the force applied by the strings. Sometimes I think folks are trying too hard and overthinking this truss rod thing. If you know what you're doing and use premium materials, the original single rod patented by Gibson in 1923, installed in a straight slot close to the back of the neck will do all you'll need a rod to do. I think simple is worth something, and in this case, simple is also lighter, which I think is a big plus.
In 1973 or so, I was so confused to first understand that Thaddeus McHugh's 1923 patented truss rod (assigned to the Gibson Mandolin and Guitar company) was installed with a "frowning" curve! ( you can very easily visually identify the early Gibsons done this way because the truss rod cover is positioned quite a good distance from the nut, way up on the headstock) 73decb.a2cdn1.secureserver.net/wp-content/uploads/2015/02/Patent-1923-US1446758-Gibson-Truss-Rod.pdf Perplexed, I made three maple test neck blanks, one with a straight rod, and one each smiling and frowning curves. I can report that they all did the same amount of work, and all worked fine. Turns out (an engineer can help you with this) that the small amount of curve in the rod will Not induce any noticeable effect by "Straightening" the rod, and thereby applying a significant force vector as a result. The forces are tiny, and just don't amount to much, if anything in the real world. It turns out that the action of this simplest kind of rod is to compress the back of the (remember how stretchy maple, in particular, is) neck. The tropical hardwood typically used for the fingerboard, reinforced with wedged - in metal frets has tremendous strength in compression, and so is extremely resistant to shortening, while the neck material is much less resistant, and Voila, just like a bi-metallic element, curvature is induced in the opposite direction that the strings are acting. It's all about compression, and near zero about straightening. Don't believe it? just make you own test necks! For the rod to work well, it needs to be installed as close to the back of the neck as it safely can be. You can think of this original truss rod design as a (hopefully!) unbreakable string on the "other side" of the neck. For the origin of this idea, have a look at the Gibson "U" harp guitar made in the very early 19oo's that sports an exterior turnbuckle style adjustable truss rod flying in the air where it can be seen!!! www.google.com/url?sa=i&url=https%3A%2F%2Fwww.harpguitars.net%2F2010%2F10%2F06%2Fharp-guitar-paleontology%2F&psig=AOvVaw1hfgn7BVEix7-YmNtWX1Qn&ust=1714655203222000&source=images&cd=vfe&opi=89978449&ved=0CBIQjRxqFwoTCMjNo8TC7IUDFQAAAAAdAAAAABAE
@@kenparkerarchtoppery9440 So interesting. I imagined that shaping the channel would give us a lot of say over the functional length of the rod. Thanks for the insights here, Ken.
Are you familiar with Trevor Gore's work? I know your design philosophy is largely based on making everything as light as possible, but he suggests that adding mass(sides in particular) can have a very beneficial effect on the sound and efficiency of the instrument. While analyzing simulations, I couldn't help but think that the same principles he talks about for sides, applies to necks as well. It would seem to me that the ideal neck is as stiff as possible, while being as heavy as possible without causing neck dive or other ergonomic issues. Paying attention to the resonant frequency would probably be important as well. I would love to hear your thoughts.
Light as possible isn't really how I think about it, although I can certainly see how it could be said to be my thing. My instrument of inspiration is the violin "family", which includes viola and cello. The contrabass, or double bass has its origins in the viol family, which are older designs and were fretted with tied-on frets. It's quite a leap from the violins to an archtop guitar, largely due to the earthshaking difference that violins are played with another instrument, the bow, about 99.5% of the time. Violins are light, and easy to energize with the bow, capable of enormous power, and spectacularly sensitive to the player's efforts. Without the bow to plow power into the string, guitars need to be built carefully in order to be efficient and have any hope of having a useful dynamic range, or to satisfy exceptional players with its sensitivity, power, and range of tonal colors. There are many paths to the mountaintop, and, especially recently, some choose to make heavy, stiff instruments that are good at reflecting energy, a lot like most speaker cabinets. This has been claimed to be more efficient than traditional, relatively lightweight designs by some builders and players. I won't argue, but I am not interested in exploring this side of the street. I try to make my guitars evenly supple, so that every surface and part has a chance a adding to the power and richness of the note. I have heard lots of praise for Mr Gore's work, and would be delighted to meet him and talk shop. He certainly is in good company in his rigid box thinking, a case could be made that the field is swinging in this direction. Me, I like the idea of creating a box that wiggles freely in response to the tiny energy we guitarists are able to apply with our fingertips and plectra. Oh, resonant frequency, this is a deep exploration, but I can say without hesitation that it's a bad idea to tune your box to the pitch of an open string. I have heard many flat-top (ever hard of these?) guitars, many built by folks who should know better, which are tuned to 83 Hz, the pitch of the low E string. This results in a wildly imbalanced condition, making this one note louder and more consonant than any other, and it's a comically bad idea, unless you play everything in that key, and want a pedal point on every tune. Neck stiffness in an important goal, and I think it's a big benefit if you can achieve it without making the neck too heavy for the sake of balance on the leg or the strap. Neck heavy designs are a non-stop irritation to most players, who have enough to deal with without acting as a skyhook 24-7. I'll point out that my minimal area headstock design helps dramatically to minimize weight at the end of a long lever, and, everything else being equal, improving balance. It might be fun to arrange a Socratic discussion about the fundamental challenges in guitar design with some of you curious, serial commentators!
@@kenparkerarchtoppery9440 Thank you for taking so much time to respond Ken! A discussion with people in this community would certainly be very cool. I find it amazing that someone could learn enough to build an acoustic guitar, but still make a such a fundamental mistake about resonant frequency. Have you ever measured the resonant frequency of your necks?
I see a lot of people putting CF stiffening rods somewhere in the middle of the neck, approximately near the neutral axis. This seems (almost) pointless to me. Am I wrong? Doesn't the stiffening need to be considerably off the neutral axis?
You, sir, are not wrong, and as you suggest, stiff supportive material is more efficiently applied at a distance from the neutral plane. The pultruded rods that are commonly used in this way are quite large in section, are made of a huge number of fibers, and can work OK because of overkill stiffness. On the Parker Fly design we used a strip of carbon about 1", 25 mm wide, and .005", .127 mm running down the center of the back of the headstock, neck shaft, and onto the body. This little whisper of material was enough to shut off the creep problem permanently because it was applied in the most advantageous place. Of course a sledgehammer will kill a fly, with potential ramifications. The other negative issue with using the pultruded sections is their use of non-optimal resin (that is, resin chosen primarily for its utility in the high-speed pultrusion process, and not so much for its superior mechanical properties, as we mentioned) to bond the carbon fibers.
Single rod: yeah, but do they not need to be curved as their initial state, and therefore need to be in a curved channel, and be held in place with a curved hardwood ‘filler’ glued over the of them?
As I mentioned somewhere, this is correct. As long as the rod is on the other side of the neutral plane, it can curve either way, or be straight, because its' job is to shorten the back of the neck by getting shorter itself.
Thank you for the latest segment of the neck by Parker. Great information. Now can your devoted fans be put out of their curiosity dilemma and actually see you muck goo and black fibers onto a matchbook thin piece of exotic and or otherwise Ken approved wood with the magical metal bits at microscopic intervals? Come on Buddy yer killing my Curiosity Bone here, it’s been aching for seven very entailed knowledge and research detailed teasers (for myself, as I have spent many years devouring such minutiae filled areas of luthiers writing )……..ya gotta build me one on camera . Now I remember that you said that you were going to, and I am calling you out on it 😂. So many variables, so few hours in the month 😊. Addendum- followed the link s and the sound was totally lacking in both Stradivarius guitars, according to my ears ( tinnitus not compensated for), having been trained on 1950s to current timeframe. The video of your delivery where Tommy E and friend tested a new Parker. The richness difference is astounding, volume weak, almost like hearing a ukulele on steroids versus a world class polished diamond vs. a river stone. Now I have had the wonderful experience of a Stradivarius played by a master, which I equate to your current level of skill and material abilities. It was probably top shelf at that era, but to my preference, yours is light years preferable. Thanks for expanding my understanding further.
I know it's comfising to talk with these terms sometimes, but the strings are loaded in tension, so the structure they attach to is loaded in compression on the front "side" of the neutral plane, and in tension on the back side. Have another look at my "diving board" example.
Do you know if anyone has done a carbon fiber truss rod. Carbon rod and anchor with a threaded socket on one end, potentially lighter and with a smaller footprint than steel.
@@kenparkerarchtoppery9440 I once considered using a guitar string on the back of the neck as the "truss rod" - complete with its own tuning peg to adjust the tension. I never seriously pursued the idea.
It seems like this is nearly always the right move, “Just enough, Never too much” “Keep it simple, Stupid” (KISS) “Simplicate and add more lightness” “Shortest line between 2 points” Please feel free to add your own! When you can get the job done correctly with a nut and a screw, I think you can feel pretty relaxed about that, It’s a dependable pair!
Everyone seems so adamant that truss rods are the greatest invention ever, but having owned some vintage martins and other older guitars with steel reinforcement I'm not sure I really see the appeal. Martin, danelectro and harmony all used steel and you almost *never* hear of any of them having warped necks, too much relief, back bows, twists etc. On the other hand, I've worked on so many instruments with maxxed out rods, backbows, twists, stripped nuts, broken rods, poorly installed rods that don't push against anything, rods that compress the wood rendering them useless etc. There is a LOT that can go wrong with adjustable truss rods, and many guitars end up with severely warped necks, stripped truss rod nuts, and other problems. One day when I get back around to building I think I will just use the D-tubes. Rock stable and lightweight, almost impossible for them to fail, and a neck that will require very little maintenance. There are most likely tonal benefits as well. Typically if a neck does not have the truss rod engaged and pushing up against the wood it will negatively impact the tone, that problem doesn't exist with stationary reinforcements.
I strongly agree that the Allred D Tube is a fabulous solution for many builders. My experience has been that they improve the neck's sonic behavior, lighten the neck in the process. In retrofitting one to an early '50's Epiphone archtop with a replacing the original, hopeless rod of unusual and awful design, all the hot and dead spots disappeared. I believe this can be expected by a correctly installed D tube, quite a benefit! I myself no longer use adjustable truss rods in my own work, and I can tell you that the reason you can buy this tube is that it was designed by my buddy JB Allred who, when I showed him my carbon reinforced neck design that I'm in the middle of explaining to you, wondered something like "What a great solution, stiffness and torsional strength together! I wonder what might be a good design for this idea to be structured for other builder's use?" I think he did a great job with his D tube designs. I agree that truss rod failures are more common than many would suspect. Lots of neck failures can be traced to the awful manufacturing tolerances that many guitars are built to, period stop. Many production necks start out with terrible defects, and then creep comes along for the ride. Many of these defects are beyond the abilities of ANY truss rod to address. The other big issue continues to be that folks unfamiliar with the adjustment protocol (often assisted by inebriated bravado) seem convinced that extreme forces in the tightening direction will be tolerated by the neck. This is not so, and occurrs with some frequency. If ever a rod needs more than a trivial adjustment in the tightening direction, for many years now, I will stop everything, completely remove the adjusting thingie, and lubricate the threads thoroughly with high-pressure grease. Here, anything is better than nothing, even olive oil will work. Beyond the welcome lubrication, the issue is corrosion between the threaded parts, of which nothing good will come. As a repairman for 15 years, I can assure you that on the other hand, many, many guitars w/o adjustable rods are Far from optimal, just ask the hundreds of customers who paid good money for me to remove frets, reshape the fingerboard with the exacting precision required, and re-installed frets. Many of my customers were pros, and plenty of them had connective tissue problems, sometimes ending their careers. I just don't believe that most guitars are anything like optimally setup, and that's too heavy a burden to ask a player to bear. I always thought it was my job to make the playing of the guitar as effortless as can be, and have spent decades getting good at it.
Kiesel guitars use (2) pultrusioned carbon fiber rods on either side of the truss on some of their guitars. At least, after watching your video, I assume they're pultrusioned rods. Ha They show it in a factory tour video on youtube.
We all have to prioritize our concerns as instrument designers/builders, and one of mine has always been the weight of the truss rod. In the '70's I used a double rod for exactly the reason you cite, and found them to work very well. If the weight of the rod doesn't seem to be a concern for you, fair enough. Having repaired thousands of guitars with and without adjustable truss rods, I can claim lots of experience over many years. I feel confident in saying that Thaddeus J McHugh's original design adjustable single truss rods (every Gibson since 1923, and every Fender ever, not to mention Taylor and many, many other examples) work very well and rarely pose a problem. When they do, evidence shows that often the rod was wildly over-tightened by someone hoping to correct a non-truss-rod-correctable problem by applying extreme force. Rods just don't break or otherwise fail when adjusted correctly, as a rule, with a handful of memorable exceptions. It's hard to imagine a more efficient and cost-effective solution. In my world, doubling the weight of a single rod that is a proven, reliable design seems not exactly wrong, but ill advised.
@@kenparkerarchtoppery9440 but the bass strings just go to the headstock? I’m callin that a soundbox with bridge to the nut. At what point is it a lyre or a harp? This is great I’m just so glad to even have this conversation. Great videos I love em.
Thanks! Someone just asked me if I rely on notes for these segments, and I said "notes?". Here's an example of how they might have helped. Thanks for catching this.
@@uburoibob Hi Bob! Fly Guitar rods were always the same design, and the long part is .078", or about 2mm steel music wire, the exact same alloy as a plain string for a guitar. This is an elegant, well tested alloy of iron and other metallic spices which has proven to be an excellent load-carrying material. The breaking strength of these rods exceeded 1500 pounds, so way stronger than needed! The reason I switched from the .062", or 1.5mm braided cable I first used when prototyping the Fly in the mid '80's was that the cable needed lots of adjustment to get it tight and do its' job of holding tension. The music wire stretches much less, as anyone who tunes a guitar knows.
just posting to let you know that UA-cam/Google keeps unsubscribing me from this channel, against my will and wishes. three times now. your other viewers who read this may want to check and verify their "subscription" to you as well. it's not my imagination- there is chatter about the problem elsewhere online. i guess youtube is going to push their crap on you one way or another, subscriptions be damned.
I'm the wrong generation to be good at this stuff, but I just asked my tech team (youngsters in the know), and it seems like the problem is in your court, and can only be corrected on your device. What I do in this kind of situation is find someone younger to press a few buttons for me. Good luck, I hope you can resolve it easily. Remember when computers made their debut and we were told that life was gonna get way easier, and we wouldn't need paper anymore?
Hi, sorry this was offline for a while - had to make a couple last minute corrections. Back now! John Guth video editor for Ken Parker Archtoppery
Hi John,
Great video, I noticed a typo in the 4:30 writing : the imperial to metric is inverted. 82lb is 37kg and 92lb is 42kg. I hope it's not too late to correct.
Frank Ford. National treasure. Thank you Frank for everything you put up on the web! RIP Thanks Ken for another great video.
I completely agree. Frank was a wonderful person who helped us all by sharing his experience and discoveries as a brilliant guitar whisperer. Any reader unfamiliar with his work should check out Frets.com
Hello Mr. Parker,
First of all, I apologize for the length of this comment. I am very thankful to you for making the Archtoppery series. I have been watching all of the videos for several years now, and it’s not only fascinating, but I find it cathartic to watch along (particularly on the longer form videos) as you transform these materials into functional works of art.
I am a fan of archtops, and I own several Gibsons and Epiphones from the 30s. If I could ever commission a guitar from you, that would be a dream come true.
I became interested in your work about 3 years ago when I acquired a 1994 Galaxy Gray hardtail Fly in a massive trade I did with a (now) friend. He told me that he purchased it directly from you in Rochester in 2004 when you were getting out of the solid guitar phase. He also said that it was a special order that the customer never paid for, and you held onto since 1994. Whether or not that is accurate is somewhat irrelevant to me, but if it’s true, I think it would be cool.
I had never touched a Fly before, but I was aware of their existence. Upon becoming the new owner of the instrument, I very quickly became somewhat obsessed with learning as much about you and your instruments as possible, as among the 100 or so guitars I’ve owned in my time, I’d never experienced anything like the Fly. Let’s just say that it impresses me from an engineering perspective more so than any other instrument that I’ve ever touched. It plays so well that it almost feels like cheating.
I’ve joined various forums and scoured the internet to find out as much about you as possible, and I’ve learned quite a lot from you thus far. In my book, you are a truly inventive pioneer like Antonio Torres, Loyd Loar, Les Paul, Leo Fender, etc., but you are also able to create instruments with the beauty and elegance equal to Antonio Stradivari.
I look forward to anything new that you want to share. Again, thank you.
Wow, what a wonderful letter. Thanks for your extravagant praise!
Here's a comment that I'll be sure to show my wife!
I can't tell you how much I love my job. What a privilege to have found it as a young punk. I was just another lost 20 year old to whom the world of business and the goal of material acquisition just looked empty and dull to me.
When I saw someone expertly use a hand plane to take gossamer shavings of a black walnut plank. It looked like a magic trick to me, and I never looked back.
Still rainin', still dreamin'.
love the historical recap, thanks for your knowledge Mr Ken, truly invaluable material
Glad you enjoyed it
Love learning from someone that understands the historical value and yet is always willing to break from “tradition” in order to improve design.
Thanks for your enthusiasm!
I guess I don't think of myself as breaking from tradition, which, it turns out, is a continuum. I think that all of us contemporary builders are adding to the time line, and thereby a part of the tradition of improving designs to suit the needs of contemporary musicians.
I have always been fascinated by the accomplishments of my predecessors, and especially by their expert and efficient hand tool use before electric motors changed craftsmanship forever.
Usually when folks are asked what guitars they consider traditional, they cite ones that they admire most. Often these are ones they wish they could afford that were built before they were born.
Tradition is in the eye of the beholder!
One of my favorite traditional instruments is a hollow log and a couple of sticks.
It's my pleasure!
Ya know…it’s really crazy…I ran into a young man in the desert of California…and he was playing one of your acoustics…I had a friend of mine with me, who is a musician and they had an impromptu jam back and forth on the side of the road…
You make some amazing guitars man….
Thanks!
Simple trust rod like Gibson or even Fender one is a perfect design ... I agree. You said what I'm thinking for many years now!! M Parker, you are my hero!!
Thanks, it's hard to beat simple that works!
As always, a very informative video about guitar structural properties.
Glad you liked it!
I love the history lesson in this video.
Thanks!
Excellent presentation!
Glad you liked it!
Ken. I look forward to all your videos. Always a refreshing re-think on what are sometimes dogmatic beliefs in lutherie. This one is no exception.
I totally misunderstood the single true rod. I assumed that it was set in the neck on a curve. (The ends being up and the middle pressed down into the pocket by a wood plug?) .and that when tention is applied, it wants to straighten. Kind of like how an archtop bridge applies the vertical vector of the string load to the top based on the break angle. The whole time, it was just tention. 🙄
Compression actually
People do use rods like that. Not really viable on thin current necks, because if you use a lot of curvature, the strip of wood in the middle becomes too thin, or you cross over the neutral plane, which robs you from all your mechanical gains.
Double action rods are better, in my opinion. Not because they can act both ways, but because they can apply a lot of balancing force without big compressive loads, which wood does not like.
This can be confusing, and I suppose you could think of it either way, but I suspect that we're not arguing that the steel rod is loaded in tension when the truss rod is tightened, and thereby induces a compressive load on the wood in the neck. If this simple nut and bolt is located properly within the neck, this action will shorten the back of the neck considerably more than the fingerboard side of the neck, counter-acting the compressive load applied by the strings, thereby straightening the curve that the strings induce.
One man’s opinion! But this man is the man!
One of many, my friend!
I wonder.. Wouldn't you need a two-way trussrod in order to acieve the needed relieve with this super stiff neck construction? I sometimes install a truss for my nylons because the tension isn't enought to get enought back bend. Thanks for sharing 🙏
I'll go into the details of my neck plan, and the nuts and bolts of how I anticipate and allow for the string's forces in real time pretty soon. Guessing, I have discovered, is a mistake, as you mention. Measuring under load is key.
Hey Ken Well done as usual interesting as im about to install a D -Tune into the same type Epiphone archtop as you are describing i was trying to find your # to chat about it as this is a new process for me and want to make sure of success Your description has given me confidence to move forward. In case u your wondering who the hell this is its Peter Meyer who use to do repair at Diamond Cove Music .i now happily work from my basement in Maine .These vids you are doing are a great contribution to the art so thanks!!
Call me, Peter, if you haven't done this yet. I still have the big poplar fixture I built to hold the guitar, and would be delighted to let you use it. Glad you're digging the series!
A wider flatter dual action truss rod just under the fingerboard might allow for a thinner neck. Solid bars on either side of the adjustable rod, instead of a solid bar underneath it. The geometry would have to be designed so it still bends up and down, not sideways in some manner. OTOH, I'm able to re-carve a stock dual-action truss rod neck down to 20mm thick without issues - and 20mm is probably thin enough from a player's perspective. You're right about the weight savings with carbon fiber reinforcement. The carbon fiber tube necks I made were insanely light - especially the triple tube neck.
Sounds like you're fooling around in the deep end of the pool. Good for you! Keep scratching your noggin' and have fun!
Very educational. I make ukuleles and with nylon strings take good advantage of the light loading.
Low forces, indeed. I'm envious!
Great information Ken. I would have to agree on the hotrod/dual action rods. They aren't a very efficient design. PRS sorted out a pretty cool solution for dual action without the additional steel bar. Unfortunately, it seems the need for dual action adjustment can be solely blamed on poor materials and/or the drying process. I spent a portion of my education in the architectural engineering school before focusing on architecture... Your analysis of cantilevered beam action is spot on... Side note... I was at a guitar show in Colorado today. A few folks mentioned you were at the arch-top show last fall in Arvada and I missed it! I'll be at the show this year for sure... It will be fun to see everything that is happening in the building community.
He obviously did not go into the gory details. First of all, in order to counteract the compression of the strings, the classic rod needs to also be a compressive force. Which means, that all the material of the neck is being compressed. Wood isn't that great when it comes to compression. Sooner or later it will crush, likely the maple, which is softer.
Then, there is a problem of leverage. Since the strings are much further away from the neutral plane, in order to balance them out we need to apply significantly more force through the rod. 3 or 4 times more? Thereabouts.
No wonder people break the threads at times.
The double action rod only gently helps. The fretboard still is under compression, the maple still under tension, where it "likes" to be, and the rod is there to only apply a very small balancing force.
Yes, it's heavier. Yes, it's more expensive. I still prefer it.
Looking forward to meeting you in Arvada!
We agree. A good neck that stays put is achievable by we mortals, but you've got to do it skillfully, and use good, properly dried materials. I wonder if PRS patented their truss rod? If so, then there is a public record including good drawings in the US Patent database. After all, the trade-off for getting protection for your invention (if it IS an invention and is issued a defensible US utility Patent) is that you must describe it in enough detail so that others "skilled in the art" of your field can read your patent and discover exactly what you've invented. Amusingly, due to this and that, patents are commonly issued in error, which might only be discovered if there was a serious legal battle over rights. You can't patent an idea that was common practice in your field centuries ago and expect to defend it in court! Examples in our corner of the world include Buzzy Feiten's and Ralph Novak's patents on moving the frets and the nut around the fingerboard.
@@kenparkerarchtoppery9440 I can't remember if Paul patented that one. It's just a thin rod (3/16"?) with a right handed thread on one end and a lefty on the other. Works just like a turnbuckle... I did look up his list of patents one day and was surprised at how many medical devices he holds patents on... Apparently the guy knows a lot about wave theory - go figure!
You bring up important things, but I'll push back on your assertion about wood's poor compressional strength and refer you to multi-story post and beam buildings, along with the engineering analysis showing that chair legs could be sized at 1/8" or 3mm diameter from many species, and be fully capable of doing their jobs properly as legs if they could be kept in column.
in 15 years of experience as a repairman, I believe that broken rods are almost always the result of being hilariously/disastrously over-tightened, either due to:
1) The misunderstanding of their function and abilities
2) Lack of lubricant
3) Ethanol or other mind-altering substances' effects on the good judgement of frustrated guitar owners
4) Misguided exploratory efforts to "See what the rod can do", likely combined with one or more of the first three.
In all my days, having adjusted quite literally thousands of truss rods, I have never broken one, and really can't conceive of doing so. A person with any kind of what we call "mechanic's feel" will stop well short of applying the forces necessary to shear off a properly designed and manufactured steel truss rod of the Gibson/Fender type.
30+ years ago, my lathe and I made a sneaky set of cutters and threading tools designed to repair broken off rods in Gibsons and Fenders, and with them have been able to restore the function of any broken rods that I was presented with. I believe that one can now buy such things at Stu-Mac.
A useful tip is to wet the wood under the washer with thin CA, where it will wick deeply down into the cellular tubes reinforcing this highly loaded surface.
Add weight if you feel it's good practice, but I don't feel it's necessary, as it works against good balance, in most designs.
@@kenparkerarchtoppery9440 This has gone in an interesting direction. I agree, wood in a solely axial load is VERY strong. Off axis loading can cause the crushing of fibers @bakters mentions. My question is - how would that happen in a guitar neck? Most guitar necks experience very little dynamic force over their lifetimes. I would offer that a neck's loading is 99.9% static (I'm not going to count the wave action caused by playing). The dynamic loads that would potentially cause failure are: over tightening the truss rod, wood movement, the artist pushing on the neck to bend a note (common with some players), and maybe string changes. I have seen broken truss rods in my repairs. I haven't been the culprit, I've been the fixer. They were ALL due to two factors: 1) corrosion due to poor storage conditions (or a spill of some kind), 2) gauling or cross-threading. I don't know how people do it, but I've seen several truss rods with mushroomed and/or smashed threads. Are people hitting them with hammers?
All this said, I wonder if simply stiffening the end grain where the truss rod bears is a way to improve how it seats thus mitigating the few dynamic loads??? As for my money - I like the light weight rods I make with drill rod and a welded slug at the treble end of the neck. Simple, cheap and effective! :D
As always, thank you.
What do you think of PRS truss rod design? If i'm not mistaken, its dual action truss rod using the front of the neck and the fretboard as the "non moving" part of the truss rod. 1 rod, dual action.
This is something I was made aware of only recently by another commentator. I respect Paul very much, and am not surprised that he or someone in his company came up with a novel 2 way single rod, Bravo!
I never felt the need for an adjuster that worked in such a way in my own work. My experience showed me that a carefully built neck of premium materials was perfectly well served by the original, close-to-the-back-of-the-neck rod designed to counteract the string's forces. Over the years I have seen other embodiments claiming this 2 way thing, and although I don't see the need for it, it's nice to have it in your back pocket just in case. Kudos, and please explain to us how this one works if you can.
@@kenparkerarchtoppery9440 The principle is very simple, imagine a rod threaded at each extremities, one thread is left, the other right (not sure it's appropriately said). Well lets say 1 side threaded an the other counterthreaded.
2 little plates are "screwed" on these threads which is then embeded in the neck itself. the plates, a little larger than the rod, are inserted in grooves and are blocked in place. now, when you turn the rod clockwise, it tends to get the plates closer, counterclockwise to have them go away forme one another.
I hope it's clearly explained ;)
@kenparkerarchtoppery9440 Is it necessary to have a truss rod that can remove both back bow and forward bow? Or is being able to remove forward bow sufficient?
I note that Ebony has a very high rate of longitudinal shrink/expansion with humidity, much higher than the species used for the shaft of the neck. It seems to me that this difference could bow the neck in either direction as humidity changes from that in which the two species were glued together.
Good points. I think that two-way rods are rarely needed, and can add complexity. If the neck is built in a "normal" way, it shouldn't need adjustment in the "other" direction. There are rare exceptions, but, in my view, not enough to justify the added complexity and added weight. Having said this, it was brought to attention that PRS guitars have a 2 way rod that is also a single rod, but I confess to having zero knowledge of these, partly because I quit repairing guitars before they came out.
If anyone can explain their rod or share their experiences with them, I'd be curious to hear it.
On the long axis mis-behavior of ebony, I guess I'm not aware that it is a real thing in real life, as I've experienced it, although sometimes there can be a shrinkage problem across the grain on maple necks. Ebony varies widely, apart from the fact that there are several species marketed as Ebony, and these things make it hard to come to good conclusions about our wonderful friend Ebony.
@@kenparkerarchtoppery9440 Yeah, I don't know if Ebony is a problem from personal experience, I've just seen other luthiers say they've had problem with it bowing the neck under humidity changes.
The longitudinal shrink rate for Gaboon Ebony seems to be about 1.26% (green to ovendry). This is calculated from the radial, tangential, and volumetric numbers on wood-database. Honduran Mahogany would be 0.46%, and Douglas fir 0.15%. Maybe that's just not enough of a difference to cause significant bowing.
Thanks Ken! So, does a single action rod always require a curved channel? Also, how do you feel about the U-channel 2-way type without the 2nd rod like the low profile hot rod?
As I mentioned somewhere on the site, the rod can be curved the "right" way, the "wrong" way, or dead straight, and all of these designs will work OK as long as the attachment points are some distance from the neutral plane in order that the rod acts like it's a nice strong string on the "other side" of the neck, so as to counterbalance the force applied by the strings.
Sometimes I think folks are trying too hard and overthinking this truss rod thing. If you know what you're doing and use premium materials, the original single rod patented by Gibson in 1923, installed in a straight slot close to the back of the neck will do all you'll need a rod to do. I think simple is worth something, and in this case, simple is also lighter, which I think is a big plus.
Ken - any comments on advantages/disadvantages of a curved (variable depth) truss rod channel?
In 1973 or so, I was so confused to first understand that Thaddeus McHugh's 1923 patented truss rod (assigned to the Gibson Mandolin and Guitar company) was installed with a "frowning" curve!
( you can very easily visually identify the early Gibsons done this way because the truss rod cover is positioned quite a good distance from the nut, way up on the headstock)
73decb.a2cdn1.secureserver.net/wp-content/uploads/2015/02/Patent-1923-US1446758-Gibson-Truss-Rod.pdf
Perplexed, I made three maple test neck blanks, one with a straight rod, and one each smiling and frowning curves.
I can report that they all did the same amount of work, and all worked fine. Turns out (an engineer can help you with this) that the small amount of curve in the rod will Not induce any noticeable effect by "Straightening" the rod, and thereby applying a significant force vector as a result. The forces are tiny, and just don't amount to much, if anything in the real world.
It turns out that the action of this simplest kind of rod is to compress the back of the (remember how stretchy maple, in particular, is) neck. The tropical hardwood typically used for the fingerboard, reinforced with wedged - in metal frets has tremendous strength in compression, and so is extremely resistant to shortening, while the neck material is much less resistant, and Voila, just like a bi-metallic element, curvature is induced in the opposite direction that the strings are acting. It's all about compression, and near zero about straightening. Don't believe it? just make you own test necks!
For the rod to work well, it needs to be installed as close to the back of the neck as it safely can be.
You can think of this original truss rod design as a (hopefully!) unbreakable string on the "other side" of the neck. For the origin of this idea, have a look at the Gibson "U" harp guitar made in the very early 19oo's that sports an exterior turnbuckle style adjustable truss rod flying in the air where it can be seen!!!
www.google.com/url?sa=i&url=https%3A%2F%2Fwww.harpguitars.net%2F2010%2F10%2F06%2Fharp-guitar-paleontology%2F&psig=AOvVaw1hfgn7BVEix7-YmNtWX1Qn&ust=1714655203222000&source=images&cd=vfe&opi=89978449&ved=0CBIQjRxqFwoTCMjNo8TC7IUDFQAAAAAdAAAAABAE
@@kenparkerarchtoppery9440 So interesting. I imagined that shaping the channel would give us a lot of say over the functional length of the rod. Thanks for the insights here, Ken.
Are you familiar with Trevor Gore's work? I know your design philosophy is largely based on making everything as light as possible, but he suggests that adding mass(sides in particular) can have a very beneficial effect on the sound and efficiency of the instrument. While analyzing simulations, I couldn't help but think that the same principles he talks about for sides, applies to necks as well. It would seem to me that the ideal neck is as stiff as possible, while being as heavy as possible without causing neck dive or other ergonomic issues. Paying attention to the resonant frequency would probably be important as well. I would love to hear your thoughts.
Light as possible isn't really how I think about it, although I can certainly see how it could be said to be my thing.
My instrument of inspiration is the violin "family", which includes viola and cello. The contrabass, or double bass has its origins in the viol family, which are older designs and were fretted with tied-on frets.
It's quite a leap from the violins to an archtop guitar, largely due to the earthshaking difference that violins are played with another instrument, the bow, about 99.5% of the time.
Violins are light, and easy to energize with the bow, capable of enormous power, and spectacularly sensitive to the player's efforts.
Without the bow to plow power into the string, guitars need to be built carefully in order to be efficient and have any hope of having a useful dynamic range, or to satisfy exceptional players with its sensitivity, power, and range of tonal colors.
There are many paths to the mountaintop, and, especially recently, some choose to make heavy, stiff instruments that are good at reflecting energy, a lot like most speaker cabinets.
This has been claimed to be more efficient than traditional, relatively lightweight designs by some builders and players. I won't argue, but I am not interested in exploring this side of the street. I try to make my guitars evenly supple, so that every surface and part has a chance a adding to the power and richness of the note.
I have heard lots of praise for Mr Gore's work, and would be delighted to meet him and talk shop. He certainly is in good company in his rigid box thinking, a case could be made that the field is swinging in this direction.
Me, I like the idea of creating a box that wiggles freely in response to the tiny energy we guitarists are able to apply with our fingertips and plectra.
Oh, resonant frequency, this is a deep exploration, but I can say without hesitation that it's a bad idea to tune your box to the pitch of an open string. I have heard many flat-top (ever hard of these?) guitars, many built by folks who should know better, which are tuned to 83 Hz, the pitch of the low E string. This results in a wildly imbalanced condition, making this one note louder and more consonant than any other, and it's a comically bad idea, unless you play everything in that key, and want a pedal point on every tune.
Neck stiffness in an important goal, and I think it's a big benefit if you can achieve it without making the neck too heavy for the sake of balance on the leg or the strap. Neck heavy designs are a non-stop irritation to most players, who have enough to deal with without acting as a skyhook 24-7. I'll point out that my minimal area headstock design helps dramatically to minimize weight at the end of a long lever, and, everything else being equal, improving balance.
It might be fun to arrange a Socratic discussion about the fundamental challenges in guitar design with some of you curious, serial commentators!
@@kenparkerarchtoppery9440 Thank you for taking so much time to respond Ken! A discussion with people in this community would certainly be very cool. I find it amazing that someone could learn enough to build an acoustic guitar, but still make a such a fundamental mistake about resonant frequency. Have you ever measured the resonant frequency of your necks?
I see a lot of people putting CF stiffening rods somewhere in the middle of the neck, approximately near the neutral axis. This seems (almost) pointless to me. Am I wrong? Doesn't the stiffening need to be considerably off the neutral axis?
You, sir, are not wrong, and as you suggest, stiff supportive material is more efficiently applied at a distance from the neutral plane. The pultruded rods that are commonly used in this way are quite large in section, are made of a huge number of fibers, and can work OK because of overkill stiffness. On the Parker Fly design we used a strip of carbon about 1", 25 mm wide, and .005", .127 mm running down the center of the back of the headstock, neck shaft, and onto the body. This little whisper of material was enough to shut off the creep problem permanently because it was applied in the most advantageous place.
Of course a sledgehammer will kill a fly, with potential ramifications.
The other negative issue with using the pultruded sections is their use of non-optimal resin (that is, resin chosen primarily for its utility in the high-speed pultrusion process, and not so much for its superior mechanical properties, as we mentioned) to bond the carbon fibers.
Thanks Ken!
Your welcome, this is big fun for me!
Single rod: yeah, but do they not need to be curved as their initial state, and therefore need to be in a curved channel, and be held in place with a curved hardwood ‘filler’ glued over the of them?
No, they work even when straight.
As I mentioned somewhere, this is correct. As long as the rod is on the other side of the neutral plane, it can curve either way, or be straight, because its' job is to shorten the back of the neck by getting shorter itself.
Thank you for the latest segment of the neck by Parker. Great information. Now can your devoted fans be put out of their curiosity dilemma and actually see you muck goo and black fibers onto a matchbook thin piece of exotic and or otherwise Ken approved wood with the magical metal bits at microscopic intervals? Come on Buddy yer killing my Curiosity Bone here, it’s been aching for seven very entailed knowledge and research detailed teasers (for myself, as I have spent many years devouring such minutiae filled areas of luthiers writing )……..ya gotta build me one on camera . Now I remember that you said that you were going to, and I am calling you out on it 😂. So many variables, so few hours in the month 😊. Addendum- followed the link s and the sound was totally lacking in both Stradivarius guitars, according to my ears ( tinnitus not compensated for), having been trained on 1950s to current timeframe. The video of your delivery where Tommy E and friend tested a new Parker. The richness difference is astounding, volume weak, almost like hearing a ukulele on steroids versus a world class polished diamond vs. a river stone. Now I have had the wonderful experience of a Stradivarius played by a master, which I equate to your current level of skill and material abilities. It was probably top shelf at that era, but to my preference, yours is light years preferable. Thanks for expanding my understanding further.
Thanks, and I promise I won't leave anything out!
I think a guitar feels the string load under tension, not compression, but maybe I'm not thinking about it correctly.
I know it's comfising to talk with these terms sometimes, but the strings are loaded in tension, so the structure they attach to is loaded in compression on the front "side" of the neutral plane, and in tension on the back side. Have another look at my "diving board" example.
Do you know if anyone has done a carbon fiber truss rod. Carbon rod and anchor with a threaded socket on one end, potentially lighter and with a smaller footprint than steel.
Looks like I need to film another truss rod segment in depth. Carbon is great in tension, but so is music wire! More on this, stay tuned...
@@kenparkerarchtoppery9440 I once considered using a guitar string on the back of the neck as the "truss rod" - complete with its own tuning peg to adjust the tension. I never seriously pursued the idea.
Cycfi research has a post about a carbon fiber truss rod
Does a dulcimer has a neck?
I guess this is an existential question, right? So it's either no neck or all neck, don't you think?
I appreciate the case for truss rod simplicity: Use what you need and no more!
It seems like this is nearly always the right move,
“Just enough, Never too much”
“Keep it simple, Stupid” (KISS)
“Simplicate and add more lightness”
“Shortest line between 2 points”
Please feel free to add your own!
When you can get the job done correctly with a nut and a screw, I think you can feel pretty relaxed about that, It’s a dependable pair!
Everyone seems so adamant that truss rods are the greatest invention ever, but having owned some vintage martins and other older guitars with steel reinforcement I'm not sure I really see the appeal. Martin, danelectro and harmony all used steel and you almost *never* hear of any of them having warped necks, too much relief, back bows, twists etc.
On the other hand, I've worked on so many instruments with maxxed out rods, backbows, twists, stripped nuts, broken rods, poorly installed rods that don't push against anything, rods that compress the wood rendering them useless etc.
There is a LOT that can go wrong with adjustable truss rods, and many guitars end up with severely warped necks, stripped truss rod nuts, and other problems. One day when I get back around to building I think I will just use the D-tubes. Rock stable and lightweight, almost impossible for them to fail, and a neck that will require very little maintenance.
There are most likely tonal benefits as well. Typically if a neck does not have the truss rod engaged and pushing up against the wood it will negatively impact the tone, that problem doesn't exist with stationary reinforcements.
I strongly agree that the Allred D Tube is a fabulous solution for many builders. My experience has been that they improve the neck's sonic behavior, lighten the neck in the process. In retrofitting one to an early '50's Epiphone archtop with a replacing the original, hopeless rod of unusual and awful design, all the hot and dead spots disappeared. I believe this can be expected by a correctly installed D tube, quite a benefit! I myself no longer use adjustable truss rods in my own work, and I can tell you that the reason you can buy this tube is that it was designed by my buddy JB Allred who, when I showed him my carbon reinforced neck design that I'm in the middle of explaining to you, wondered something like "What a great solution, stiffness and torsional strength together! I wonder what might be a good design for this idea to be structured for other builder's use?"
I think he did a great job with his D tube designs.
I agree that truss rod failures are more common than many would suspect.
Lots of neck failures can be traced to the awful manufacturing tolerances that many guitars are built to, period stop. Many production necks start out with terrible defects, and then creep comes along for the ride.
Many of these defects are beyond the abilities of ANY truss rod to address. The other big issue continues to be that folks unfamiliar with the adjustment protocol (often assisted by inebriated bravado) seem convinced that extreme forces in the tightening direction will be tolerated by the neck. This is not so, and occurrs with some frequency.
If ever a rod needs more than a trivial adjustment in the tightening direction, for many years now, I will stop everything, completely remove the adjusting thingie, and lubricate the threads thoroughly with high-pressure grease. Here, anything is better than nothing, even olive oil will work. Beyond the welcome lubrication, the issue is corrosion between the threaded parts, of which nothing good will come.
As a repairman for 15 years, I can assure you that on the other hand, many, many guitars w/o adjustable rods are Far from optimal, just ask the hundreds of customers who paid good money for me to remove frets, reshape the fingerboard with the exacting precision required, and re-installed frets. Many of my customers were pros, and plenty of them had connective tissue problems, sometimes ending their careers.
I just don't believe that most guitars are anything like optimally setup, and that's too heavy a burden to ask a player to bear.
I always thought it was my job to make the playing of the guitar as effortless as can be, and have spent decades getting good at it.
I have a bad experience with a single action rod. The neck backbowed, so it became useless
It's always something, and there's always a fix.
NO! The pedal steel is all body, which contains a neck analogue! 😉
OK, duly noted, I'll stay out of this one, you're on your own.
Kiesel guitars use (2) pultrusioned carbon fiber rods on either side of the truss on some of their guitars.
At least, after watching your video, I assume they're pultrusioned rods. Ha
They show it in a factory tour video on youtube.
Cool, this seems quite common now, and can really help a neck behave, although, as usual, it depends on the details!
5:37 normal calipers 0,005'' accuracy. Ken parker thumb calipers 0,00002'' accuracy
More confirmation that I'll need to film a show on tolerance and measuring?
haha you should make an intro song videoclip and give your show a name. that's so USA oldskool@@kenparkerarchtoppery9440
correction: 0.001''' normal calipers ;)@@kenparkerarchtoppery9440
The two-way trussrod is better in every respect, except weight. Minimal crushing involved.
We all have to prioritize our concerns as instrument designers/builders, and one of mine has always been the weight of the truss rod. In the '70's I used a double rod for exactly the reason you cite, and found them to work very well. If the weight of the rod doesn't seem to be a concern for you, fair enough.
Having repaired thousands of guitars with and without adjustable truss rods, I can claim lots of experience over many years. I feel confident in saying that Thaddeus J McHugh's original design adjustable single truss rods (every Gibson since 1923, and every Fender ever, not to mention Taylor and many, many other examples) work very well and rarely pose a problem. When they do, evidence shows that often the rod was wildly over-tightened by someone hoping to correct a non-truss-rod-correctable problem by applying extreme force. Rods just don't break or otherwise fail when adjusted correctly, as a rule, with a handful of memorable exceptions. It's hard to imagine a more efficient and cost-effective solution.
In my world, doubling the weight of a single rod that is a proven, reliable design seems not exactly wrong, but ill advised.
Theorbo is half a neck? Haha
Maybe 4.5 necks?
@@kenparkerarchtoppery9440 but the bass strings just go to the headstock? I’m callin that a soundbox with bridge to the nut. At what point is it a lyre or a harp? This is great I’m just so glad to even have this conversation. Great videos I love em.
@1:42 you say "mid 1900s" when i'm sure you meant "mid 19th century".
cheers; thank you for publishing so much of your knowledge.
Thanks! Someone just asked me if I rely on notes for these segments, and I said "notes?".
Here's an example of how they might have helped. Thanks for catching this.
...has anyone ever used a tensionable braided cable to counter the string load, rather than the traditional truss rod...?
The truss rods for the Fly are basically that. There's no reason for it to be braided though.
Yes, I have, take a look at the truss rod shows.
The Parker Fly?
@@uburoibob Hi Bob! Fly Guitar rods were always the same design, and the long part is .078", or about 2mm steel music wire, the exact same alloy as a plain string for a guitar. This is an elegant, well tested alloy of iron and other metallic spices which has proven to be an excellent load-carrying material. The breaking strength of these rods exceeded 1500 pounds, so way stronger than needed! The reason I switched from the .062", or 1.5mm braided cable I first used when prototyping the Fly in the mid '80's was that the cable needed lots of adjustment to get it tight and do its' job of holding tension. The music wire stretches much less, as anyone who tunes a guitar knows.
just posting to let you know that UA-cam/Google keeps unsubscribing me from this channel, against my will and wishes. three times now. your other viewers who read this may want to check and verify their "subscription" to you as well. it's not my imagination- there is chatter about the problem elsewhere online. i guess youtube is going to push their crap on you one way or another, subscriptions be damned.
I'm the wrong generation to be good at this stuff, but I just asked my tech team (youngsters in the know), and it seems like the problem is in your court, and can only be corrected on your device. What I do in this kind of situation is find someone younger to press a few buttons for me. Good luck, I hope you can resolve it easily. Remember when computers made their debut and we were told that life was gonna get way easier, and we wouldn't need paper anymore?