Hey Tom, great video! Get yourself a box of the 4.4 x 8.4 Kimwipes. Put a single layer of the Kimwipe on the part and then put the optical flat on top. Now slowly drag the Kimwipe out from between them and you will have a perfectly clean interface where you will be able to manipulate the flat to get the band spacing and direction you desire. Also fold a piece of paper into an inverted hat shape and put it in the vise and then grab the lap with the paper lined vise so all that lapping debris does not lube your vise but stays on the paper. ATB, Robin
The way people figured out how to measure things is astounding to me. I mean, I understand that the measurements my digital calipers spit out come from a measurement on a wave but to then see that broken down into it's base components and then expanded on in another direction like this is a real treat.
The McD’s lunch tray is the real gem of precision in today’s video! This is an absolute killer for knocking out ignorance! Warm water changing shapes because yes, we are capable of working on THAT level in our shops. Damn dude, you are awesome. Thank you.
I have seen many, many machines, but it is my first time I see a machine like this!!! Thank you for Sharing :) I just love your work. Have a very good year and Hope to see lots and lots of video from you. Lots of love from Iran....:)
Brings back memories of running lapping machines when I worked as a hydrostat mechanic. We had a six inch diameter optical flat that I kept locked in a drawer so that the hammer and chisel mechanics couldn’t bust it. We had several lappers and the largest was about 60” in diameter. I would batch test and adjust the rings in or out to compensate for wear on the lapping surfaces which in turn adjusted the flatness of the plates being lapped. In that set-up, flatness was a constantly moving target.
Hey Tom... first time I've seen the optical testing... very impressive... thanks to you I learned something today. Thank you for sharing your vast knowledge and being so casual about it... very much appreciated!
I wish I could find one of those old Marvel band saws for a reasonable price. I worked in three shops that had them and the were indeed a marvel. At one shop, the automatic feed had gone out years before and I was told that they couldn't get parts for it. I took it apart during my breaks and found out that all that was wrong was the pin on the worm gear was sheared and the clutch was worn out. Since the clutch was actually made from cork sheeting, I took a cork bulletin board and peeled the cork off it and that became the new clutch. It was still working just fine a year later when I left that job for another.
Multiple lessons in one video - very nicely done, Tom. It would be interesting to see other ways to check flatness for the small shop, but I think you've covered that in previous videos if I recall correctly. Hard to keep track after all of this time. Search button to the rescue! Thanks for sharing, sir. Tom Z
Very interesting video. Back when I was a SeaBee in Vietnam, we actually had a lapping plate to rebuild fuel injectors or maybe the pumps on diesel engines. We didn't have an optical flat to test it however. I don't think we were looking at that level of precision. It seems to me the lapping plate was 6 to 8 inches square.
As a non-machinist (went to school for welding finished school and changed my mind) I am blown away at that finish. I didn't even know steel could be that mirror like. Nice work! Also making that "Lap" (?) was very interesting I have never seen that done and those cross hatches are really awesome looking. Any chance you could do a video on making one of those from start to finish?
Excellent video, as usual, thanks Tom for sharing. I'm pretty sure you would enjoy telescope mirror grinding and lapping. Much of the same, but with the added fun of figuring a concave or convex shape (paraboloid, ellispoid, etc.) down to a few nanometres (when we're lucky). Hours of fun! For the final lapping, we commonly use pitch laps and cerium oxide.
Fascinating. I was part of a tour group in the early '60s where the company made hydraulic motors in Southern California. The swash plates (I recall that being the name) were lapped and measured on a machine like that. As I recall they were used for aircraft flight controls
In my carer as a mech. in a power plant, I lapped safety valves on every overhaul.On the finish lapping ,would use 1000 grit,and just keep lapping and wiping the valve seat until the compound would break down so fine that the seat would would become a mirror finish,,,the seat would become so smooth it would become a filament finish,or you could see a flashlite filament in the seat...
You ought to do a video in more detail on the feed mechanism on your Marvel saw. The way that works has to be one of the cleverest engineering designs I have ever seen.
probly the first time I've seen optical flats on youtube not a bad video at all I half expected a explination on how photons are particals the follow eachother around in waves and esentialy yer using a lazer to determin flatness its good to know how mr wizard love that saw that was what the press forming was bout ha awesome aqisition
Excellent information, Tom. Especially the part at the end evaluating with the optical flat. It's interesting because the laps you made look just like the laps used to polish mirrors for reflector telescopes. I believe the grinding material is also Aluminium Oxide; need to look see whether the Mirrors are ever finished with a diamond compound. I suspect the assessment of how well the mirror is made would be how concentric the bands are in the optical test setup the mirror fabricator uses. Thanks!
That optical flat, I saw one a couple of weeks ago for the first time in a "how its made" video about the starret micrometer production. Ofcourse in "how its made" tradition lacking all seriously interesting stuff. Thanks for the explanation I now understand the idea and it is pretty cool! It might also be horrible to have when you are a perfectionist.
Hip Hip Moiré on those patterns. Your lapping series solved my much lower resolution problem. I'll be lapping the bottoms of a new set of cast iron skillets [very nicely cast, but with a fine sandpaper-like as-cast surface from the casting sand]. I want the bottoms both smooth and flat so as to be non-abrasive and to get greater surface contact with the glass on an induction cooktop. Thanks Tom
Tom's on a roll with introducing us to crazy ass new stuff most folks have never heard of before (me included!), the polariscope, the optical flat and a monochromatic light source by lapmaster. Being that I know a thing or two about lasers the "monochromatic" light source particularly piqued my interest, as most light sources emit a variety of wavelengths which we perceive as "white" (or yellow), I had thought that lasers were the only "lights" that we produce that operate on a single wavelength but that seems to not be the case, entirely anyways. Fascinating.
Thanks Tom. Did the gauge block wring to the base? Did you finish up buying an autocollimator? You mentioned that at one stage. If so, set the V on a sine plate and collimate off it. You will get a very good indication of how accurate your V block is. Calibrate your sine plate with zero degrees (ie no blocks), Any lapped surface will provide a good enough reflection to do that. Gauge blocks make great mirrors in fact. Do you think the grooves were strictly necessary when using such fine abrasive? My understanding they're more for coarse abrasive so the excess that doesn't charge the lap has somewhere to go. Not such a factor with fine abrasive. One thing to mention to your viewers is to grind the lap before changing to a finer abrasive. The lap is charged and that layer needs to be removed before going finer. Your surface grinder is sensational and you do beautiful grinding. I've never seen that saw before. A very nice piece of kit, thanks for showing us that.
Hi Just found your channel, Awesome stuff, I used to lap carbon seal plates among other things back 25 yreas ago while building up Pratt & Whitney JT3 gas turbines for Boeing 707's we have come along way since then but I feel sorry for the kids these days they cant even read a mic or a Verynear haha let alone use a light source. I tell people and they are amazed what we used to do I worked over in Holland at the Frank Whittle engine shop for a few months and got the nick name MacGyver from my supervisor as they had all the kit but I was working out the moments of the fan blades for balance without a computer lol not rocket science back when i started we had to work everything out on paper lol cheers Phil.
It has been many years since my time as a job shop machinist , Though I remember a crystal similer to what you used and I believe it was a type of Calcite Optical Feldspar ... One of the Gem quality version of the Sun stone used by Nordic Vikings to site the sun for navigation... Could be wrong or close. I think I have forgotten way more than I have learned in my lifetime... Many Blessings , SMR
You need some KimWipes. They are ubiquitous in labs, and with people who use microscopes. They are made from special paper they leaves no lint, and absorb an impressive amount of moisture considering they are closer to feeling like printer paper than tissue. I use them by the case in the lab, they are fairly cheap.
I allway think that lapping back and forward motion gives a curved surface. they do lenses and parabolic mirrors in a similar way i think. should it be a fun test to lap in one direction and see how the lines go then? interesting stuff by the way. thanks and cheers.
Thanks, I will look forward to more lapping videos. I think you get monochromatic light out of any LED. You might using and LED flashlight and see what happens. Could save the rest of us a bundle for a light source..
Hey Tom, when making a lap out of cast iron can you use any old grade of cast iron or is there one that does a better job? i've been seeing several different grades of cast iron in german ebay and have worked with some really bizarre stuff and so it would be good to know if there is any discernible difference a guy needs to watch out for? cheers mike
I ask this few times in the past I really like the blanchered ground table you got that's thick I would love it if you talked about it in one of your next videos , what is Blanchard ground ?
Ive spent the last couple weeks watching your content. Super impressed with your extensive knowledge base. Thanks for sharring. Ive asked about the feed drive on that Marvel saw before and i dont mean to beat the horse here but im still a bit fuzzy on one thing. The long rod that runs the length of the saw i assume is the driven member. So it enters the migic box where the hand wheel is at. So whats in that magic box. It must skip teeth and the weight makes that either harder or easier to do. Could you elaborate on whats going on in that box and how it gets back to move the saw please. Kindest Regards
Very informative....., but a bit more of the physical background would be welcome. What does the change in line interval, i.e., smaller to larger, indicate? Direction of curvature...? What a scheme for larger surfaces....?
Another very interesting video. Not that it should change much, but are you going to recheck the parallelism and angle of the V after lapping? Also, just curious, how do you decide when mixing grits and slurry solutions is ok and when it is not? Like obviously you wouldn't use 3 micron on the same lap as 60grit....but switching from 3 micron aluminum oxide to 3 micron diamond worked fine.
You've just answered your question. It doesn't make sense to mix very different grits, but you can get away with mixing similar grits/grades, nothing bad will happen (most of the time). But normally you should stay clean (don't mix or even store different grits together - you're asking for trouble, various surface quality defects, etc.).
The grit particles break down as they are used and become smaller. So by continuing to use the lap with just a lubricant, the particles imbedded in the lap were being broken into smaller pieces and, eventually, they reduce to the size of the next grit.
A more than interesting video Tom. Information and especially videos about precision lapping is tough to find. Since I've never lapped anything even close to high precision this is simply passing along a technique I've seen mentioned in Guy Lautard's second? Bedside Reader book. They mentioned how to get surfaces lapped as parallel as possible while using a lapping plate by weighting the part at the high side so it gets lapped much quicker at that area and into being parallel. On smaller parts the magnetic base from an indicator stand and without the vertical rod might be enough to weight bias the part. But it was something I've always remembered given the accuracy they were trying for. I'd be surprised if that's anything new to you though.
Cool saw! Cool optical measurement! Thanks for showing! One question: you had the v-block going off the end of the lap partially...doesn't that mean that the middle of the v-block gets more abraded than the ends? While the ends have left the lapping block and are hanging in the air, the center is still sliding across the lapping block. Also, unless you can precisely reduce the down force as the end comes off, you'll have more psi on the center than the ends see. Net effect is that I'd guess you get a concave surface. Not by much, but maybe enough to see with optical methods? I'd also guess that unless downforce is identical and pass count is the same, you are also moving the center of the V by not removing the same material from both sides...though since it's still a V, it will still work fine as long as you don't change the planar relationship. Precision nit-picking while you wait! :-) --- Mike
Awesome video Tom. The finish you were able to get is astounding. Is there a risk of making the V-block surfaces out of square with one another? Maybe the amount of material being removed isn't enough to make a difference? The optical inspection blew my mind. Would you be up for doing a more in-depth video on that?
Sorry pal, nothing "astounding" here. It's just a quick lap, to make this thing shiny (with defects, as Tom himself mentioned in the video)... Yes, there is a danger of making things worst (squareness, parallelism, etc.).
Very interesting. I have a lap I've never used. I think I'll have to order some abrasives. Now, how about a video on testing the ground and lapped block?(amateur here) The geometry makes it interesting. Parallelism of both sides of the base, parallelism and centering of the axis of the v to the sides of the base, parallelism of the axis of the V to the base, actual angle of each side of the V away from the centerline plane down the length of the V, etc.
Tom My first knowledge of optical flats come 50 years ago when as a Sparks was put on shift with a 60 year old Sparks mate , though time spent chatting between plant breakdowns it transpired he made gauge blocks (jo blocks ) during ww11 he when into great detail how they made them and the hand lapping process using CI Lapps and optical flats to test the results , and it's a bit footy now but a optical comparitor to get them on size , one thing that did stand out was the ruff ground the blocks then during them in the ground for two years ( greased up ) before finishing, he still had a couple of rejects that still wrung together , during the same time frame in ww11 dad worked on 18 foot HBM to bore and rifle large gun barrels ( he sett them up and the operators were all female )
Really interesting subject...I'm glad you decided to tackle it! Any thoughts on frangible (silicon carbide) vs. infrangible (aluminum oxide) abrasive? I've heard/read/been told that infrangible can stick in a lap forever and ruin it.
Question from the curious..... Why would a gauge block or vee block need to be THAT flat? What would you be manufacturing that required that sort of tolerance? Optical stuff like lenses maybe?
Hey Tom, another great video. On one of your other videos I mentioned that I inherited my Grandfathers machinist tools. One of the things he made was a lapping block, it is approximately 3"x5"x1.125 thick. When I found it, it was in a leather pouch and looked like it needed a good cleaning. Watching this video, you are using Simple Green to clean up the lap block you made. Is there anything else that might work just as well, without a water based cleaning solution. I'm just worried about rust using something like Simple Green.
Hi Steve, With water based cleaners you just need to dry the part well and then apply some protective coating like LPS. The soaps help remove old grease and crud. Alternately you can clean in solvent but then you have a bunch of dirty solvent to deal with. Thanks for the comment. Cheers, Tom
Nice saw! Now how do you get your block to look like the Mit? More lapping? I have been pondering how to do a precision bore and plunger with a clerance tolerance of .00005". I assume fine lapping would be the best method?
I sure don't know a whole lot about it just to be clear Brian, but one old school method was to cast a lead lap inside the bore of precision rifle barrels and around a smaller diameter rod, pull that out and charge it with abrasives. Then work that through the barrel to average out the lead/lag errors and bring the bore to final size and surface finish. Multiple laps are needed since you change the abrasive grit and size as the bore and rifling gets better. Split expanding and reducing aluminum, brass, or cast iron laps both male and female are used by the guys who build ultra high performance competition model engines and they can get some amazing precision and surface finishes. The laps are slowly rotated and reciprocated sort of like the automotive cylinder honing machines. Some use just a drill press to rotate the lap at the slowest speed possible and the part is moved up and down by hand. Since the lap itself slowly wears it gets more accurate for straightness and roundness. That in turn starts doing the same to the bore. The whole process sounds pretty mickey mouse and low tech, but the results are supposed to be much much better than one would think these simple processes can do. Getting two parts to fit with the tolerance needed is the tough part obviously. But those two areas where they do high precision hand lapping and might be where you can dig up further information. And exactly how they get the size as well as the required surface finish and flatness on gauge blocks is something I've always wanted to know as well. I did know about how there checked with the light bands, doing it consistently and to millionths is what I can't seem to find out.
Tom, does your Marvel have the hydraulic blade tensioner? That's one real nice thing to have on these saws. Changing blades by yourself is really fun......................not. You really do have to be a three handed paper hanger. Another nice brand of vertical band saws are the Roll In type saws
Just curious about the "11 milions of an inch" between bands? Light has a wave length of about 500 nano meters. which is (if my conversion is correct) about 0.2 ten thousands of an inch , or about 20 millionths of an inch. So wouldn't the distance between bands be 20 millions of an inch, or is there some funky trick that gives half that resolution? I played with some optical flats nearly 30yrs ago when i was an engineering intern at a very high precision tool making company and got to spend a few weeks in their metrology lab. This is the first time since then that i have seen an optical flat and those fringe pattern lines. I remember the Lab manager claimed they had the next best length/flatness etc standards in the Country (Australia) after the National Standards. The metrology lab was intended primarily for internal use but they had a pretty healthy side business calibrating other peoples masters to theirs. Cheers
edit WRONG! : I think it adds up nicely. The distance between bands represents only half the wave length, from peak to peak. That gives a wave length of 22 millionths, or approx 600 nm which places us at the end of the orange spectrum and beginning of the red spectrum. Interesting optical effect this, and it resembles the physics experiment from high school where a laser beam passes through two slits in a dark glass, producing two semi circular waves on the back side. Two wave top ads up to produce a bright red dot (wave maximum), two valleys produce a block spot (wave minimum) and a top and valley neutralize if I remember correctly. This experiment proves that light is both a particle movement and a wave movement. The experiment can even be done with water. I don't know if this is the effect at play, optics is a strange science. I remember when Tom demonstrated that stress light thingy, never seen stranger thing (at least not this year (or was it last)).
The fancy light he's using is ~11 millionths of an inch (280nm). Typically you'd see a couple helium light bands as the flatness tolerance for seal components.
Krap101, I pretty sure that's not correct, since it would be outside the visible light spectrum which has wave lengths in the range 400-700nm. The fancy-ness of that light is that it produces a single wave length of light, not multiple wave lengths like most lights. As Arnljot already pointed out the feature Tom was reffering to with width 11 Millions of an inch, was created by half a wave length, with the full wave length being around 22 millions of an inch. I had wrongly understood he was talking about the pitch of the bands, when he was actually talking about the "gap", eg Lh side of one black band to RH side of next black band, which is obviously half a pitch and thus 11 milions of an inch. Cheers
Apologies, the wavelength of the light is 587.6 nm. A helium light band is half of that. The width of the bands and the distance between is determined by the air gap. The wavelength of the light determines the "resolution" of the measurement, so the lower the wavelength, the higher the resolution.
The Marvel Saw is by far one tool that a man would be proud to own let alone use, Thanks Tom for showing.
The optical flat is fascinating! Never heard of that before. Thank you for sharing this with us.
I agree with your statement. Fascinating!Learnig every day, thanks to people like Tom.
Hey Tom, great video!
Get yourself a box of the 4.4 x 8.4 Kimwipes. Put a single layer of the Kimwipe on the part and then put the optical flat on top. Now slowly drag the Kimwipe out from between them and you will have a perfectly clean interface where you will be able to manipulate the flat to get the band spacing and direction you desire. Also fold a piece of paper into an inverted hat shape and put it in the vise and then grab the lap with the paper lined vise so all that lapping debris does not lube your vise but stays on the paper.
ATB, Robin
Great suggestions!
Did I really just spend 25 minutes watching a man rub 2 pieces of metal together? Seriously, incredible work. Thanks!
The way people figured out how to measure things is astounding to me. I mean, I understand that the measurements my digital calipers spit out come from a measurement on a wave but to then see that broken down into it's base components and then expanded on in another direction like this is a real treat.
The McD’s lunch tray is the real gem of precision in today’s video! This is an absolute killer for knocking out ignorance! Warm water changing shapes because yes, we are capable of working on THAT level in our shops. Damn dude, you are awesome. Thank you.
Wow. That gives me new respect for the gauge blocks. I mean I know they're good, but those lines are straight!
I don't find videos like this boring at all. There is something very hypnotic about it. Almost like an asmr video, but without the weird noises
Very Interesting Tom, the monochromatic light is amazing, The Marvel saw is pretty cool too!
Your a great teacher and mentor, thanks for the your time in show us your great knowledge around your workshop.
Extremely interesting subject. Thanks for the education and take care Tom!
I have seen many, many machines, but it is my first time I see a machine like this!!! Thank you for Sharing :) I just love your work. Have a very good year and Hope to see lots and lots of video from you. Lots of love from Iran....:)
Brings back memories of running lapping machines when I worked as a hydrostat mechanic.
We had a six inch diameter optical flat that I kept locked in a drawer so that the hammer and chisel mechanics couldn’t bust it. We had several lappers and the largest was about 60” in diameter.
I would batch test and adjust the rings in or out to compensate for wear on the lapping surfaces which in turn adjusted the flatness of the plates being lapped.
In that set-up, flatness was a constantly moving target.
Very cool to see that. Thanks for sharing Tom.
Hey Tom... first time I've seen the optical testing... very impressive... thanks to you I learned something today. Thank you for sharing your vast knowledge and being so casual about it... very much appreciated!
Used a saw just like that working maintenance in a steel mill good memories thanks for the video 👍
I wish I could find one of those old Marvel band saws for a reasonable price. I worked in three shops that had them and the were indeed a marvel. At one shop, the automatic feed had gone out years before and I was told that they couldn't get parts for it. I took it apart during my breaks and found out that all that was wrong was the pin on the worm gear was sheared and the clutch was worn out. Since the clutch was actually made from cork sheeting, I took a cork bulletin board and peeled the cork off it and that became the new clutch. It was still working just fine a year later when I left that job for another.
Super cool, like the optical flat shows some cool info about the surface finish
Very cool seeing the optical flat and the interference rings! Great video.
Not boring at all. Nice saw, thanks for showing us.
Multiple lessons in one video - very nicely done, Tom. It would be interesting to see other ways to check flatness for the small shop, but I think you've covered that in previous videos if I recall correctly. Hard to keep track after all of this time. Search button to the rescue!
Thanks for sharing, sir.
Tom Z
That is one marvelous bandsaw you have in your shop.
Interesting video, I wondered how true flatness was determined, now I have a glimpse of how, & what to look for. Thanks Tom!
Very interesting video. Back when I was a SeaBee in Vietnam, we actually had a lapping plate to rebuild fuel injectors or maybe the pumps on diesel engines. We didn't have an optical flat to test it however. I don't think we were looking at that level of precision. It seems to me the lapping plate was 6 to 8 inches square.
So that is what optical flats are fore. Really cool. Thanks for sharing.
As a non-machinist (went to school for welding finished school and changed my mind) I am blown away at that finish. I didn't even know steel could be that mirror like. Nice work! Also making that "Lap" (?) was very interesting I have never seen that done and those cross hatches are really awesome looking. Any chance you could do a video on making one of those from start to finish?
Excellent video, as usual, thanks Tom for sharing. I'm pretty sure you would enjoy telescope mirror grinding and lapping. Much of the same, but with the added fun of figuring a concave or convex shape (paraboloid, ellispoid, etc.) down to a few nanometres (when we're lucky). Hours of fun! For the final lapping, we commonly use pitch laps and cerium oxide.
Fascinating. I was part of a tour group in the early '60s where the company made hydraulic motors in Southern California. The swash plates (I recall that being the name) were lapped and measured on a machine like that. As I recall they were used for aircraft flight controls
Super interesting bit about the optical flat and monochromatic light source!! More, please! I would like to see how flat you can get your V block.
Abraham Lincoln: Give me six hours to chop down a tree and I will spend the first four sharpening the axe.
Tom Lipton: Hold my beer.
In my carer as a mech. in a power plant, I lapped safety valves on every overhaul.On the finish lapping ,would use 1000 grit,and just keep lapping and wiping the valve seat until the compound would break down so fine that the seat would would become a mirror finish,,,the seat would become so smooth it would become a filament finish,or you could see a flashlite filament in the seat...
Always nice to see some of the stuff we were supposed to learn at school, for real! Thanks for sharing! ;)
You ought to do a video in more detail on the feed mechanism on your Marvel saw. The way that works has to be one of the cleverest engineering designs I have ever seen.
probly the first time I've seen optical flats on youtube not a bad video at all I half expected a explination on how photons are particals the follow eachother around in waves and esentialy yer using a lazer to determin flatness its good to know how mr wizard love that saw that was what the press forming was bout ha awesome aqisition
Excellent information, Tom. Especially the part at the end evaluating with the optical flat. It's interesting because the laps you made look just like the laps used to polish mirrors for reflector telescopes. I believe the grinding material is also Aluminium Oxide; need to look see whether the Mirrors are ever finished with a diamond compound. I suspect the assessment of how well the mirror is made would be how concentric the bands are in the optical test setup the mirror fabricator uses. Thanks!
Correction: Silicon Carbide.
Fascinating to watch that Gauge block is amazing! Thank you. Learning new stuff is fun :)
That optical flat, I saw one a couple of weeks ago for the first time in a "how its made" video about the starret micrometer production. Ofcourse in "how its made" tradition lacking all seriously interesting stuff. Thanks for the explanation I now understand the idea and it is pretty cool! It might also be horrible to have when you are a perfectionist.
Hip Hip Moiré on those patterns. Your lapping series solved my much lower resolution problem. I'll be lapping the bottoms of a new set of cast iron skillets [very nicely cast, but with a fine sandpaper-like as-cast surface from the casting sand]. I want the bottoms both smooth and flat so as to be non-abrasive and to get greater surface contact with the glass on an induction cooktop. Thanks Tom
very interesting demo on how to measure flatness with light. camera work was very good.
VERY interesting....enjoyed!
Tom's on a roll with introducing us to crazy ass new stuff most folks have never heard of before (me included!), the polariscope, the optical flat and a monochromatic light source by lapmaster. Being that I know a thing or two about lasers the "monochromatic" light source particularly piqued my interest, as most light sources emit a variety of wavelengths which we perceive as "white" (or yellow), I had thought that lasers were the only "lights" that we produce that operate on a single wavelength but that seems to not be the case, entirely anyways. Fascinating.
it is really amazing as to the tools that are out there and to how fine measurements can be taken down to good Tom keep em coming
Thanks Tom. Did the gauge block wring to the base?
Did you finish up buying an autocollimator? You mentioned that at one stage. If so, set the V on a sine plate and collimate off it. You will get a very good indication of how accurate your V block is. Calibrate your sine plate with zero degrees (ie no blocks), Any lapped surface will provide a good enough reflection to do that. Gauge blocks make great mirrors in fact.
Do you think the grooves were strictly necessary when using such fine abrasive? My understanding they're more for coarse abrasive so the excess that doesn't charge the lap has somewhere to go. Not such a factor with fine abrasive.
One thing to mention to your viewers is to grind the lap before changing to a finer abrasive. The lap is charged and that layer needs to be removed before going finer. Your surface grinder is sensational and you do beautiful grinding.
I've never seen that saw before. A very nice piece of kit, thanks for showing us that.
The things I learn from you, I swear I can not learn anywhere else.
Nice Tom, the only things I have lapped are valves! Using what would amount to the equivalent of 32 grit paper! Enjoyed.
Excellent video Tom, specially the optical inspection part.
Hi Tom,
Very interesting subject...
Enjoyed... ;)
Cheers, Pierre
Outstanding Tom! 😃👍
Hi Just found your channel, Awesome stuff, I used to lap carbon seal plates among other things back 25 yreas ago while building up Pratt & Whitney JT3 gas turbines for Boeing 707's
we have come along way since then but I feel sorry for the kids these days they cant even read a mic or a Verynear haha let alone use a light source. I tell people and they are amazed what we used to do I worked over in Holland at the Frank Whittle engine shop for a few months and got the nick name MacGyver from my supervisor as they had all the kit but I was working out the moments of the fan blades for balance without a computer lol not rocket science back when i started we had to work everything out on paper lol cheers Phil.
It has been many years since my time as a job shop machinist , Though I remember a crystal similer to what you used and I believe it was a type of Calcite Optical Feldspar ... One of the Gem quality version of the Sun stone used by Nordic Vikings to site the sun for navigation... Could be wrong or close. I think I have forgotten way more than I have learned in my lifetime... Many Blessings , SMR
That was cool!
Thanks for the vid. You know us geeks are lapping it up...
That's a very cool saw. Thank you for the video
Great video and very informative. Thanks Tom.
Wow, you're truly the Norm Abram of the machine shop.
Saw envy. Nicely done.
You've got my curiosity peaked for what the supper precise v-block is going to be use for. ??!!
Love that saw , never seen such a beast .
Tom wondering if an attachment for laping could be made to work with a shaper?
Not really. That's why they make proper lapping machines...
Beautiful job
very cool Ox. Thanks for the lesson
You just have a way of moving on' fantastic show👍👍👍👍👍
Great video. You are a consummate professional. Thank you.
You need some KimWipes.
They are ubiquitous in labs, and with people who use microscopes.
They are made from special paper they leaves no lint, and absorb an impressive amount of moisture considering they are closer to feeling like printer paper than tissue.
I use them by the case in the lab, they are fairly cheap.
19:18 OMFG and then laughed so hard i choked on my spit!
Very interesting Tom, great content.
CALGON, take me away! Awesome video. Thanks for the informative video!
You taught me something again. Thanks.
Not boring! Very interesting.
Oxtool you learn something new every day
I allway think that lapping back and forward motion gives a curved surface. they do lenses and parabolic mirrors in a similar way i think. should it be a fun test to lap in one direction and see how the lines go then? interesting stuff by the way. thanks and cheers.
Thanks, I will look forward to more lapping videos.
I think you get monochromatic light out of any LED. You might using and LED flashlight and see what happens. Could save the rest of us a bundle for a light source..
Hey Tom,
when making a lap out of cast iron can you use any old grade of cast iron or is there one that does a better job?
i've been seeing several different grades of cast iron in german ebay and have worked with some really bizarre stuff and so it would be good to know if there is any discernible difference a guy needs to watch out for?
cheers
mike
I ask this few times in the past I really like the blanchered ground table you got that's thick I would love it if you talked about it in one of your next videos , what is Blanchard ground ?
Ive spent the last couple weeks watching your content. Super impressed with your extensive knowledge base. Thanks for sharring.
Ive asked about the feed drive on that Marvel saw before and i dont mean to beat the horse here but im still a bit fuzzy on one thing. The long rod that runs the length of the saw i assume is the driven member. So it enters the migic box where the hand wheel is at. So whats in that magic box. It must skip teeth and the weight makes that either harder or easier to do. Could you elaborate on whats going on in that box and how it gets back to move the saw please.
Kindest Regards
Oh it was very interesting thanks Tom
Very informative....., but a bit more of the physical background would be welcome. What does the change in line interval, i.e., smaller to larger, indicate? Direction of curvature...? What a scheme for larger surfaces....?
the last minute showing and explaining the lines was the best
now that was very cool Tom.
Another very interesting video. Not that it should change much, but are you going to recheck the parallelism and angle of the V after lapping? Also, just curious, how do you decide when mixing grits and slurry solutions is ok and when it is not? Like obviously you wouldn't use 3 micron on the same lap as 60grit....but switching from 3 micron aluminum oxide to 3 micron diamond worked fine.
You've just answered your question. It doesn't make sense to mix very different grits, but you can get away with mixing similar grits/grades, nothing bad will happen (most of the time).
But normally you should stay clean (don't mix or even store different grits together - you're asking for trouble, various surface quality defects, etc.).
Seems to me if you mix say 220 grit with 100 grit you still are only lapping with the 100
The grit particles break down as they are used and become smaller. So by continuing to use the lap with just a lubricant, the particles imbedded in the lap were being broken into smaller pieces and, eventually, they reduce to the size of the next grit.
In a future lapping video you should see if you can lap two parts flat enough to get them to wring together.
A more than interesting video Tom. Information and especially videos about precision lapping is tough to find. Since I've never lapped anything even close to high precision this is simply passing along a technique I've seen mentioned in Guy Lautard's second? Bedside Reader book. They mentioned how to get surfaces lapped as parallel as possible while using a lapping plate by weighting the part at the high side so it gets lapped much quicker at that area and into being parallel. On smaller parts the magnetic base from an indicator stand and without the vertical rod might be enough to weight bias the part. But it was something I've always remembered given the accuracy they were trying for. I'd be surprised if that's anything new to you though.
with those kinds of finishes and precision, im now verry much wondering if you could sharpen tools on a lap instead of using a stone....
Cool saw! Cool optical measurement! Thanks for showing!
One question: you had the v-block going off the end of the lap partially...doesn't that mean that the middle of the v-block gets more abraded than the ends? While the ends have left the lapping block and are hanging in the air, the center is still sliding across the lapping block. Also, unless you can precisely reduce the down force as the end comes off, you'll have more psi on the center than the ends see. Net effect is that I'd guess you get a concave surface. Not by much, but maybe enough to see with optical methods? I'd also guess that unless downforce is identical and pass count is the same, you are also moving the center of the V by not removing the same material from both sides...though since it's still a V, it will still work fine as long as you don't change the planar relationship.
Precision nit-picking while you wait! :-)
--- Mike
Great demonstration Thanks for sharing
MUCH better than watching grass grow, although trucks rusting might give it a run for the money...just kidding, great video. Thanks, as always.
Awesome video Tom. The finish you were able to get is astounding. Is there a risk of making the V-block surfaces out of square with one another? Maybe the amount of material being removed isn't enough to make a difference? The optical inspection blew my mind. Would you be up for doing a more in-depth video on that?
Sorry pal, nothing "astounding" here. It's just a quick lap, to make this thing shiny (with defects, as Tom himself mentioned in the video)...
Yes, there is a danger of making things worst (squareness, parallelism, etc.).
Great stuff Tom. Thanks.
Very interesting. I have a lap I've never used. I think I'll have to order some abrasives.
Now, how about a video on testing the ground and lapped block?(amateur here) The geometry makes it interesting. Parallelism of both sides of the base, parallelism and centering of the axis of the v to the sides of the base, parallelism of the axis of the V to the base, actual angle of each side of the V away from the centerline plane down the length of the V, etc.
Tom
My first knowledge of optical flats come 50 years ago when as a Sparks was put on shift with a 60 year old Sparks mate , though time spent chatting between plant breakdowns it transpired he made gauge blocks (jo blocks ) during ww11 he when into great detail how they made them and the hand lapping process using CI Lapps and optical flats to test the results , and it's a bit footy now but a optical comparitor to get them on size , one thing that did stand out was the ruff ground the blocks then during them in the ground for two years ( greased up ) before finishing, he still had a couple of rejects that still wrung together , during the same time frame in ww11 dad worked on 18 foot HBM to bore and rifle large gun barrels ( he sett them up and the operators were all female )
really interesting Tom
thanks Will
Very cool Tom. Science!! Hahahaha. Well done as always:)
I can't press the "like" more than 1 times? This video is awesome! THX!
Really interesting subject...I'm glad you decided to tackle it! Any thoughts on frangible (silicon carbide) vs. infrangible (aluminum oxide) abrasive? I've heard/read/been told that infrangible can stick in a lap forever and ruin it.
Question from the curious.....
Why would a gauge block or vee block need to be THAT flat?
What would you be manufacturing that required that sort of tolerance? Optical stuff like lenses maybe?
wow, learn something new every day. And I thought my shiny finish on my surface ground drill press was flat. lol
Hey Tom, another great video. On one of your other videos I mentioned that I inherited my Grandfathers machinist tools. One of the things he made was a lapping block, it is approximately 3"x5"x1.125 thick. When I found it, it was in a leather pouch and looked like it needed a good cleaning. Watching this video, you are using Simple Green to clean up the lap block you made. Is there anything else that might work just as well, without a water based cleaning solution. I'm just worried about rust using something like Simple Green.
Hi Steve,
With water based cleaners you just need to dry the part well and then apply some protective coating like LPS. The soaps help remove old grease and crud. Alternately you can clean in solvent but then you have a bunch of dirty solvent to deal with. Thanks for the comment.
Cheers,
Tom
Nice saw! Now how do you get your block to look like the Mit? More lapping? I have been pondering how to do a precision bore and plunger with a clerance tolerance of .00005". I assume fine lapping would be the best method?
I sure don't know a whole lot about it just to be clear Brian, but one old school method was to cast a lead lap inside the bore of precision rifle barrels and around a smaller diameter rod, pull that out and charge it with abrasives. Then work that through the barrel to average out the lead/lag errors and bring the bore to final size and surface finish. Multiple laps are needed since you change the abrasive grit and size as the bore and rifling gets better. Split expanding and reducing aluminum, brass, or cast iron laps both male and female are used by the guys who build ultra high performance competition model engines and they can get some amazing precision and surface finishes. The laps are slowly rotated and reciprocated sort of like the automotive cylinder honing machines. Some use just a drill press to rotate the lap at the slowest speed possible and the part is moved up and down by hand. Since the lap itself slowly wears it gets more accurate for straightness and roundness. That in turn starts doing the same to the bore. The whole process sounds pretty mickey mouse and low tech, but the results are supposed to be much much better than one would think these simple processes can do. Getting two parts to fit with the tolerance needed is the tough part obviously. But those two areas where they do high precision hand lapping and might be where you can dig up further information.
And exactly how they get the size as well as the required surface finish and flatness on gauge blocks is something I've always wanted to know as well. I did know about how there checked with the light bands, doing it consistently and to millionths is what I can't seem to find out.
Tom, does your Marvel have the hydraulic blade tensioner? That's one real nice thing to have on these saws. Changing blades by yourself is really fun......................not. You really do have to be a three handed paper hanger. Another nice brand of vertical band saws are the Roll In type saws
I would kill for a video showing how ol' Johansson did it with a Singer sewing machine.
Just curious about the "11 milions of an inch" between bands?
Light has a wave length of about 500 nano meters. which is (if my conversion is correct) about 0.2 ten thousands of an inch , or about 20 millionths of an inch.
So wouldn't the distance between bands be 20 millions of an inch, or is there some funky trick that gives half that resolution?
I played with some optical flats nearly 30yrs ago when i was an engineering intern at a very high precision tool making company and got to spend a few weeks in their metrology lab. This is the first time since then that i have seen an optical flat and those fringe pattern lines.
I remember the Lab manager claimed they had the next best length/flatness etc standards in the Country (Australia) after the National Standards. The metrology lab was intended primarily for internal use but they had a pretty healthy side business calibrating other peoples masters to theirs.
Cheers
edit WRONG! : I think it adds up nicely. The distance between bands represents only half the wave length, from peak to peak. That gives a wave length of 22 millionths, or approx 600 nm which places us at the end of the orange spectrum and beginning of the red spectrum.
Interesting optical effect this, and it resembles the physics experiment from high school where a laser beam passes through two slits in a dark glass, producing two semi circular waves on the back side. Two wave top ads up to produce a bright red dot (wave maximum), two valleys produce a block spot (wave minimum) and a top and valley neutralize if I remember correctly. This experiment proves that light is both a particle movement and a wave movement. The experiment can even be done with water. I don't know if this is the effect at play, optics is a strange science. I remember when Tom demonstrated that stress light thingy, never seen stranger thing (at least not this year (or was it last)).
Arnljot Seem oh yeah the 11 millionths would be 1/2 a wave. thanks
The fancy light he's using is ~11 millionths of an inch (280nm). Typically you'd see a couple helium light bands as the flatness tolerance for seal components.
Krap101, I pretty sure that's not correct, since it would be outside the visible light spectrum which has wave lengths in the range 400-700nm.
The fancy-ness of that light is that it produces a single wave length of light, not multiple wave lengths like most lights.
As Arnljot already pointed out the feature Tom was reffering to with width 11 Millions of an inch, was created by half a wave length, with the full wave length being around 22 millions of an inch.
I had wrongly understood he was talking about the pitch of the bands, when he was actually talking about the "gap", eg Lh side of one black band to RH side of next black band, which is obviously half a pitch and thus 11 milions of an inch.
Cheers
Apologies, the wavelength of the light is 587.6 nm. A helium light band is half of that. The width of the bands and the distance between is determined by the air gap. The wavelength of the light determines the "resolution" of the measurement, so the lower the wavelength, the higher the resolution.