Single Point Threading, Want to do it better ?? Watch This Video.
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- Опубліковано 28 сер 2019
- STOP cutting threads based on the depth !! If you have any chance at ever single pointing a quality thread, PLEASE WATCH THIS VIDEO. You'll be glad you did.
Need Thread wires? Let me know -- aiproductinfo@gmail.com - Наука та технологія
Joe, I single point thread quite often. I've watched a ton of your videos pertaining to threading. I'm going to put some of this knowledge to work. Thank you for taking the time to mess with the cameras so we can all learn from a master.
Joe you should do a screw cutting 101 video. Im a beginner. Ive watched your thread cutting videos and understand some of it but that pitch diameter, pitch wires,etc gets me everytime. Using the subjects of all 6 of your thread cutting videos and show how to cut an internal and matching external thread from start to finish
I recommend getting a Machinery's Handbook and reading that section. It gives a very in-depth tutorial of the process and the measurement. There is a lot of info in there so take your time reading through it.
Great video Joe! Interchangeability of parts, was the key to the industrial revolution! "During the Industrial Revolution of the 19th century, machines took over most of the manufacturing work from men, and factories replaced craftsmen’s workshops. The event that laid the groundwork for this monumental change was the introduction of interchangeable parts,..."
I watched this video three times. I get it. I made a proper 5/8 X 18 bolt using the wires. Cut a 2A thread to perfection.
I used a tap for the bore to check my work (pretending I sent my bolt out to bumfa) my bolt fit perfectly. I could not have asked for a better fit. Not loose and smooth as glass.
I was going to buy a thread mic. Not any more.
Joe, I love you man!
Joe!
You made that very easy. Just completed a A3 5/8x24 and pulled a PD of .64872
And yes, threaded away from the head stock.
Nice. Pass it on.
Joe, I watched your first video at the time, and it completely changed the way I thread. Your technique is just so much easier. 👍👍
Joe i have been a subscriber for quite a while and have like you always threaded from the headstock but you are the only one who has explained measuring of threads in a way i could understand now my threads are wonderful and acurate with great fitment thank you so much for the rime you take to teach
Your videos are a joy to watch. I've learned a lot about machining, but even more important - you're really good at taking technical concepts and breaking them down into clearly understandable pieces. That's a rare and valuable talent - thanks for sharing it with us!
Thank you.
You are by far the best at the theoretical side of machining, very informative video thanks for the effort
Thank you.
Another good one Joe! Your videos have made my threading 100 percent better with far less pucker factor. Keep up the good work!
I blow people away at work with the strategies I learn from your channel. Im constantly learning, retaining and applying what your teaching all the time
Thanks.
Joe, from a retired Firefighter/medic and ED - RN, you are SMOKIN' ! I love that passion, coupled with an overt knowledge/ mastery of your field. For all of us chip makers seeking your level, please keep it coming. The info is astounding. Thank you!
A much better explanation of pitch diameter and thread root then when I served my apprenticeship 30 years ago. Please keep up the great work.
As always awesome video. I don't even know words to describe how good work You are doing. Thank You Joe 👍
Thanks Joe, watched your first video just by chance, I think the day it came out. It changed my life, literally. Been a self employed Engineering and Building contractor 45+ years now I’m a student at my local community college learning machine tool. I gotta say I’m amazed at how and what the capabilities are in this trade. Thanks for the time and effort you put into your videos, you’re running a business I get it, trust me.
Thanks. I squeeze them in as life permits.
As always, Joe, despite being an old man - I learn something every time.
Thank you.
I love your rants, Joe. I learn something every time. Keep it up! 😁
Hi Quinn. Thanks for stopping by.
Hi Joe, cheers again for another super video. I have posted before asking if you could do something on cutting a double helix thread. Keep up the pearls of wisdom.
Wow, you have really great content and speak very well on camera, with good explanations. No idea it's only been 3 years; I've been following your work since pretty near the beginning. Graduated UT last year, keep enjoying Austin and doing great work.
I admire your understanding to the math of machining,in all your videos you never cease to amaze me
Thanks. Its helps to really understand whats going on.
Hi Joe I love your videos and I think i have learned something from every one of them, You are truly a master of the trade. and even if i think you have a funny accent you are easily to understand. you give us the information in a direct and professional manner and i thank you for sharing it. Ever since I saw your video on turning threads in reverse and the the cutting tool upside down I was hooked. So easy and simple . I have done it this way ever since and I even flex my fingers while doing it the same way you did. I look forward to all your videos and even though some may not apply to me I still take something away from them. Keep up the good work. Best Regards from Australia
Everything You Wanted To Know About Threads--But Were Afraid To Ask. Thank you, Joe!
Even when fired up Joe is still a nice guy! Never change Joe Pie, never change
Thanks. I do have my moments.
Great video Joe, can't wait for the next one...
I always learn from You, the easy way. Simple and clear, to stick for ever. Great channel !
Thanks for watching.
Awsome rant Joe. Such a good video I didnt realize I needed this until after watching it. Bang up job buddy.
“The metric system - since 1792, the system trusted by 15/16 of the world.” This Old Tony.
Wouldn't that be 93.75% in metrispeak.. Just say'n.
so you guys know fractions and decimal aren't the same as Imperial and Metric
Its only a different language. Its not more precision.
Brad Mcgrath someone forgot to convert the imperial joke to metric standard for you to get it.
You know America did pass metrification laws, 1975. And I quote wiki:
The U.S. Metric Study recommended that the United States implement a carefully planned transition to the principal use of the metric system over a decade. Congress passed the Metric Conversion Act of 1975 "to coordinate and plan the increasing use of the metric system in the United States".
All I can say is thank goodness you got frustrated at some videos. You have been turning out top notch videos that I have enjoyed and learned from.
Thank you very much for all your comments over the years. I have noticed.
Thanks for the video. Your tid-bits and how to videos really help.
Hi Joe, Phil here from Western Australia. Love your videos. I’m a late starter learning a few machining skills in my sixties. Your no nonsense, cut to the chase style suits me perfectly. Keep up the great work...Phil
Thanks Phil.
This really helps me understand the the enigma of something that is actually kind of almost simple.
Good advice if you're doing small quantities , using threading tools that you ground yourself. Good advice for anyone just starting out.
However, for producing larger quantities, I recommend buying carbide insert threading tools, and using pitch mikes in place of wires.
To check internal threads, consider just using the appropriate tap, instead of a plug gauge. It's cheaper, and will bring a thread that's a little undersize up to proper size.
If you plan to hit the checkbook, buy hard gages and stop messing around.
Thanks Joe, your videos are the best
Very good Joe! Always good solid info. Tom
thanks for all the videos...Have not found a vid on dressing threads...had a part come into my shop and ithe part had been over torqued. needed to dress the threads on both the cap and the bolt..did not have machines to do it and know one in town would do it...got a video to show me how...when I get the machines...thanks for all the good info and help...thanks
Great video Joe, as always!
Thanks Joe. Great insight as usual sir.
Nice rant, from someone who knows what he is talking about. Thanks, Joe!
Cheers, Gary
really enjoy watching your videos. thanks
Like so many things, there's a BIG difference between the guy doing it as a hobby and the guy doing the work professionally.
Thread fit is a STANDARD and just because the off the shelf nut fits doesn't mean it's right and conforms to the standard.
One of the reasons a thread fit is specified is because a certain degree of thread engagement is needed for strength of the connection or perhaps a degree of "looseness" is needed to allow space for sealants, locking compounds etc..
Good info, Joe!
Thanks.
enjoyed the lesson, please keep them coming...
Thanks for stopping by Chuck. Always good to get a comment from you.
Thankyou Joe !! Wish I was young and your apprentice you are a great teacher my friend, Mark
Thanks.
Thanks for the video Joe.
I noticed a little flustration from some of the comments. Doing machine work requires a lot of patience to get the results needed. I use many methods to get the results I need, depends on the job. I cut mostly LH acme custom threads, I sometimes use a measurement from surface to the bottom of the thread as a reference. When getting close to where I want to be, then I use a custom pitch diameter checked with wires. I have samples of most threads I do from making the original part longer than needed cutting off the extra length to use as a plug gauge. This is a great video on how to make your parts to the industry standards established to make our jobs easier. Thanks for putting this information on line for all of us to share!!! Great job 👍
You should get used to working to standards. Its a good practice.
Great job. Love the talk!
Brilliantly explained, as always !
Experience makes a great teacher . . . .
Thanks.
Thanks for sharing. I worked overseas and brought my equipment with me from the USA. We also brought parts that need to be replaced every now and then, cases of oil and air filters , starters, turbo, alternators, solenoids and relays. We did so well a 9 month job extended to 5 years with four new customers. One thing we forgot were nuts and bolts. I sent every spare minute cleaning and repairing old bolts from junk yards and bone yards. Luggage with new nuts and bolts getting stopped at the airport, the TWA guys loved me, not! Someone had the great idea to have some metric bolts cut down to imperial sized ones, bad execution wasted time and money.
It's always nice to learn from you
I saw a couple videos where folks made screws that thread both counterclockwise and clockwise, depending on the nut you use them with. They were multi-pointed threads. They look knurled, but they're definitely threaded. Have you ever encountered a real-world application? I can only think of two: Your rapid-tap device, and those screwdrivers that rotate when you push them into a screw.
I guess I need to source these wires now
thank you!
Thanks Joe. You are 100% correct! But, having said that.... Job shop machinist 40 years and I've gotten the thread wires out maybe twice (I think for a class 3 fit). I don't remember having a thread come back for poor or no fit. Hand ground high-speed, square to the work by eye, compound at 29.5,
and cut the thread. Use a nut to check it. I guess I've been making lawnmower parts all these years.
I spent the majority of my shop time in aerospace, medical and semi-conductor. Every thread had a class. I'd have to say after 40 years of luck like yours, go buy a lottery ticket.
@@joepie221 I understand, and your attention to close tolerances is quite justified. The lion's share of my shop work has been in heavy industry.....coal mines, rock quarries, well drilling, railroad, etc. Much more forgiving work. You are a master machinist and I admire your work. Thanks Joe!
I wonder how SpaceX runs their job shop. I worked with a NASA guy for a time and he wanted to verify the line voltage and that the electricity was actually supplied at 60Hz as part of a qualification package for a medical application. A generous 6 week timeline for writing and executing a qualification package ballooned into what would be a 6 month qualification package. He was chopped and I took over and I got it done in 4 weeks. Interchangeable means interchangeable. There is no "one" test. Everything of importance is checked and rechecked and checked some more. My guess is that 98% to 99% of the job shops work just like you describe, cut the threads and check them with a bolt/nut for play and call it good. I don't see that the 2% of job shops are going to start mandating that all threads be measured with thread wires. That's way too much time wasted. It is a nice video but only relevant to maybe 2% of the shops that need to do this, and they already know they have to measure and verify threads to class and they are onboard. This rant is much ado about nothing. You didn't have 40 years of good luck, sorry, you were doing things exactly as you should have done them. 40 years of cutting threads and none ever came back for poor fit or no fit says it all.
All job shops making threads than need to fit parts that are not also in their control need to stay within the tolerances specified. You're probably right 98% of the time the tolerance will fall good even with threads checked against a nut or bolt but consider the cost of the 2% of jobs that get sent back for a thread that doesn't go together or worse the thread strips in service because it's been over cut. If it's a one off part the cost and time of checking it properly is trivial. If it's a batch of parts then measuring first, last and samples will be sufficient in most cases. It doesn't take long to make a go/nogo plug for internal threads that puts you comfortably within the max/min pitch diameters. Quality is a state of mind. (Joe has it).
@@MrSailbadthesinner No arguing your point in theory. So why do 98% of job shops go with a qualitative test nut/bolt versus a quantitative test unless specified otherwise? The way Joe said it is everyone else is a sloppy lawnmower part maker. I would say the real world data doesn't support that a quantitative test is superior to a qualitative test for 98% of the work going out the door. GE was a big believer in SixSigma and where are they now. NASA was known for very high quality standards and they priced themselves out of the market. Quality must be applied in context or it becomes quality exercises. Everything must have a cost benefit.
Another great video! Thanks
I’ve been struggling lately with using a HSS tool i ground to cut single point threads. I’m confident my grind is good and my tool is square to the work and my compound is set at 29-29.5 degrees. For some reason it’s just not coming together. Going to apply some of what I’ve learned here and give it another shot. Thanks Joe. Really appreciate all your help.
Glad to do it. Feel free to reach out with issues if you need to. I'll help you solve the problem if I can.
Good video Joe. I'm sat here watching in my light blue Advanced Innovations t shirt that arrived today!
Hey MrCrispin. Good to hear from you. Thanks for wearing the shirt.
No problem. In fact I'll shoot my next video wearing it. Always thought I could be a model. Lol.
"if you have any questions...." Yeah where do I begin!? lol
A job I worked on a few years ago almost required purchasing a specialized internal micrometer that had spherical anvils (if i recall correctly) that measured pitch dia of an internal thread. Specialized and expensive. This application required actually obtaining absolute pitch dia data for engineering purposes.
Awesome topic. Thank you
Thank you Joe. I really like the mounts. I remember the days I had with the Nikonos V and the 102 & 103 strobes. Your outfit is what EVERY scuba person should have....the absolute nicest unit for photography. Thanks again for the threading instructions "professor". -Tom (Knoxville)
Thanks Tom. That light rig is very comfortable, light and bright to dive with. The G2 version is even better.
I got my first Nikonos in 1964, great camera. My underwater flash used the standard big flash bulbs of the time. Never understood how it could work in salt water but it did. Did most of my diving in the PI.
Informative info as always . I have used the DD chart since i was 14 back in 78 but you need the mating part ! I think you converted me to wires a while back & i bought a set , just have to start using them ! Glad to see my sticker made it safe , Cheers Joe .
You are on the board !!
@@joepie221 Thanks .
A technique I saw from a local agricultural/industrial machinery repair shop (old school do quicker job shop) was he used a sharp tool to get to depth and then fed the compound forward (never seen him bothered with infeeds) to widen it and leave a flat crest. This way he had to have only a few threading tools at hand.
You can set the compound inline with the part to control the root flat if you need to. Dive in with the cross slide and manipulate the flats with the compound.
Thanks Joe, love your enthusiasm!
One thing, the H/8 root of a threading tool for a specific thread makes a stronger thread because it spreads out the stress area at the thread root. If you are going to cut a lot of threads then a threading tool for the thread you are cutting is the way to go.
mosfet500 - I understand that having flats on tool tips is far simpler for making threading tools, and for leaving the most material on the workpiece. However I wonder if there's a point where rounding the corners at the tool tip to get rid of the stress riser made by the corners of the flat, would make a stronger thread?
Yes. I believe they are called 'J' threads. Lots of rounds. The crest of the mating part must also have a radius, or the corners will hit on tighter class threads.
very good lesson, thanks
As I don't have a lathe (maybe someday), I'm just a home (disabled hobby machinist on my mini mill. Working slowly towards CNC conversion, and hopefully will be able to cut threads then. Any words of wisdom would be appreciated. Keep up the great work!
Another great video.
Greetings from metric uk :-)
Great video..Thanks!
Great job!
Another informative and educational video, no surprise there! Thank you Joe. I've told you on a couple of occasions that I would love to study with you in person, but then your "shopmates" started showing up in your in your videos . . . . ummm, so yeah, anyway . . . .
Hey, that Rye Playland sticker took me way back to my childhood! Holy crap, the memories I have from that place! Definitely a New York experience! Couldn't pass a summer without at least one trip there. Just glad to know we share that place in common. Actually took my own children there when I went home to visit my mother when they were younger. Anyway, be well sir, looking forward to the next one.
Lived in north NJ for 37 years. Great part of the country.
Good job.
Excellently done... It's hard to believe it's been that long since that first video. I remember thinking here's another joker with some kind of nonsense threading hack. It's nice to be wrong sometimes.
I'm glad threading is your passion... We might have missed out on some really good content otherwise.
Thanks. I hated it originally, but a job I had fixed that problem.
Thanks Joe
I enjoy your videos and your passion for machining. I've used your threading technique ever since watching that first video. I'm soooo glad you now use a tripod! :-) The only problem I've had using the technique, since I don't practice thread cutting much on the lathe, is making sure I hit my mark on the dial. Lots of time after you run off the end of the thread with your technique but a smaller window if you miss the mark on the thread dial. This is usually solved by a few "practice" engagements with the tool moved away.
I did a video on engaging your halfnut made easier. Check it out. I agree with the "off the part" practice runs. Good practice.
@@joepie221 Yep, I've seen that video and that's how I've always done it. I just can't get to anxious on starting to applying a bit of pressure as my lathe has 24 engagement points, so not far in between them.
Brown&Sharpe, a major contributer to thread standards actually manufactured some off standard threads in their form tools. They made it so you had to buy their mounting bolts, not an off shelf bolt. Off the shelf bolts didn't fit but were dimes. B&S bolts were dollars, but they fit and the job would run.
original video is just fine, thanks ! Content is what counts !
An old model engineer once told me that once you are set up at your outside diameter for your part that you are threading and your cutting tool is at the same place , ie just touching the blank, then divide the figure 640 by the threads per inch and the result will be the depth of cut in thousandths to achieve the result. Ie 8 tpi = 640 divided by 8 gives you a depth of cut of 80 thou. This has also worked for metric threads with a little maths conversion . Always 640 regardless of number of threads. All of this dependant on tool shape etc. This has served me well over the years for what I have done but I would be interested in your comments Joe.
The ideal flat root you mentioned is not the case in some situations. Some threads REQUIRE a root radius, and a vary accurate and clean one. I worked at a place where this was the norm. These were UNJ and UNR with different variations of them. We did not cut them though, we rolled them.
Cutting tool suppliers typically only supply single point threaders with a root flat, OD, on the tip when it is a Acme, buttress or square thread. Most others have a radius that is dependent on the thread being cut. A radius is better for heat dissipation, which in turn extends tools life. This is a deep topic, why Joe is probably so passionate about it. He did a good job of an overview and pointed out the important characteristics of proper thread forms.
good stuff, thank you !
Great info thanks
Saw that video, long ago - yes, its bad but that is why I subscribed. Wonderful videos. Thank you for sharing.
It was my very first one. Thanks for sticking around.
My pleasure. Its always the student's gain when he finds a great teacher!!! :)
Joe, I watch that first shakey video a few years ago and was so impressed I subscribed and you followed up with some additional good videos. I was so impressed by your content all of a sudden and seemingly out of nowhere that I asked where you came from. (If memory serves you said New Jersey). Anyway, you started off great and just got better. Now I often see or hear other You Tuber's quoting "Joe Pie". Glad you are gentle today.
I am flattered by all the support and trust. thank you all. Yep Jersey boy. 37 years
We just had a part made for a German machine by a large machine shop. They struggled to get an internal Acme thread to fit the adjusting shaft on the machine. They had the original part and they measured the threaded shaft (20mm?) on the machine. State of the art shop, quality control lab etc. After many tries they finally got a fit. I had no idea it would be that difficult.
Metric threads on a imperial lathe never is funny because of the odd tpi you have to deal with.
Acme is NOT used with metric values!
The corresponding metric thread is a trapez.
Now why is this very important? The reason is that while their shape look the same to a naked eye they aren't. Acme has an angle of 29 degrees while the trapez has 30 degrees.
Both threads rely on a large contact area to keep wear and friction under control, use the wrong tool and you will get a very small contact point and a thread that will fail quickly.
(There are also other trapezoidal thread forms but these two are the most common)
It sounds like they had their heads stuck between a book and a computer. Sometimes old school will simplify things. If you have the mating part, measure the pitch to the best of your ability, grind a tool to match the profile, allow an appropriate amount of clearance, and cut the threads until they fit..
@@sharg0 Yep! When I saw Larry's comment I was going to make the same comment as you. Nice catch.
As expected words of wisdom.
Threading is such an interesting subject that has occupied the minds the brighter machinists for many many decades. I myself have a video on the subject that demonstrates a style of threading tool from 19th century. Very useful for times when you can't easily disengage the leadscrew as the tool lifts clear on the reverse cut. You colonials should be proud as it is an American idea.
As for 3 wires, one day i will do a video showing my one handed three wire system that requires no calculations! Interesting or what?😀
just saying but in cnc machining, when writing code with a canned cycle the min dia on male and max dia female are required along with the thread depth so the number of passes can be determined. when checking to see if threads are correct, you are right it isnt about measuring how deep but the pd and crests.
There are some decent threading videos on UA-cam Abom springs to mind straight away his finished parts are spot on he does do a nice job, but I have to say I watched your video on threading and I've done nearly all mine in that way ever since, your threading technique is brilliant that's why I do it, but your explanation of why you do it this way is something no one else has explained in detail like you have, keep up the good work Joe I'll always be watching.
Alan.
Thanks Alan. The why is just as important as the how.
Great video, and I even understood most of it. But really happy that I don't have to work to those standards. I am more like the "lawnmower repair" standard.
Nice review. Made sense to me, and only had to watch it once.
I bought a thread mic long ago, you tempt me to get wires and give it a go. be nice to have comparison if something doesn't make sense.
ASIDE Question: Cutting male threads on a CNC [OMNI GT-75 for reference] Anyway I learned thru trial and error that doing a spring pass or the final cut was too small the threads looked rough compared to doing a bigger cut on the last one.
Both were good, just not as pretty... material 303 , I just learned to do it one way but not figured out why the light cut kinda chowder-ed up the threads a little looking with magnifier. Carbide insert btw. Any insight? This was from a few years ago, and just did a memory recall. Not seen if with Brass, 17-4 etc. just the 303 , the sulfur maybe...
Little machine shop dot com is a good source of information and thread pitch wires it is where I got mine from.
Thanks again Joe.
Thank you sir for the info. What are your thoughts on the thread triangles that attach to your mics? I think I will get a set of wires coming though. Thanks for the videos.
Well said mate.
Nice cut Joe! 👍
Much cooler for The heat wave. Thanks.
My process, while I am not doing it for a living. Is to have a quality set of dies and taps. When I am within range I take of what I need until it's a perfect fit. I know this is only going to work up to a certain size until it becomes unsustainable due to size. The other thing it allows is depth of cut for a part run, you can zero out the tool depth. Obviously you have to be 100% sure of tool position to do this. But for the small volumes I do, it works great.
Wow! This video is priceless! When I was in school (a very long time ago) I wish I had metal shop teachers who were half as talented and knowledgeable as you are, Joe. Thanks so much for this excellent tutorial, and for all of your other wonderful videos.Question: There are lots of charts available that list tap drill sizes for common taps, both imperial and metric, but I have yet to find any charts at all that list recommended rod diameters for common die sizes. Why is that? If no charts exist, then please tell me how a person can find out what the recommended rod diameters are for various dies. It usually becomes a case of "Guess work" for me.THANKS AGAIN!
usually its just the nominal dimension of the thread ie. m8 thread uses 8mm rod, 1/2" threads use 1/2" rod, job done no charts needed
Hi Joe
Metric and Imperial are constantly at odds.
The Moon landings were fine with the later?
Hahaha, perfect. I was threading tonight 2.075 - 20, and I was wondering how to figure out the depth of the thread XD When I figured what it would be approximately, I used the advice from your previous video to set the depth without trig. Great right? By the time I got the thread to depth, and got a sharp crest, I had dulled the tool, so the Min. Diameter was radiused. Not a big deal, It's just to fit something else I need to turn internal threads on in the shop (Fly Cutter to fit a Shell Arbor), but good timing
Dear Joe
Another great video.
If you have a copy of "The Engineer's Black Book", the tapping drill size pages list the Pitch Diameters for you. In this book however they call it the "Effective Diameter", (perhaps because the origin of this publication is Australia where the terminology may be a bit different?).
I hope that is helpful.
Paul
I believe that term comes from mechanical engineering, treating it like 'gear pitch circle'?
www.quora.com/What-exactly-is-pitch-circle-and-its-significance-in-gears
Joe, love the videos. We use thread pitch micrometers. Do you think wires are better than thread pitch mics. Just interested in your thoughts. Keep up the videos.
I still want to know the thread depth, so I can creep up on the pitch dia. The Starrett "fish tail" allinment tool has double depth of thread listed on it for a reason.
Hi Joe
I agree with the sentiments and principles you expressed but cutting threads by using thread depth is used successfully if you follow some rules. What you said in the video definitely applies to hand sharpened tools of dubious dimensions. However if you use a precision thread cutting insert tool of known dimensions then this is a completely different scenario.
When thread milling on a CNC mill, the effective thread depth is used because it must be programmed into the machine as there is no human intervention. This is applicable to a lathe situation.
If the outside diameter of the part is machined and measured accurately, a simple formula can be applied to determine the depth of cut. Once near the target depth, the thread pitch diameter can be measured over wires. I have included a few notes below
I would appreciate your comments.
Cheers
John
THREAD MEASUREMENT WITH WIRES
The best wire diameter for 60 degree thread form is 0.57735 x Pitch
Measurement over wires = Pitch diameter + correction factor
The correction factor = 3 x wire diameter - 0.866025 x thread pitch
. If the best wire is used this reduces to a correction factor = 0.866025 x Pitch
For best accuracy use the recommended wire diameter for that pitch. The reason for this is that the wire tangent contact point is at the intersection of the pitch diameter and the flank of the thread form.
MACHINING AN EXTERNAL 60 DEGREE THREAD WITH THREAD INSERT CUTTER
Total depth of cut = (measured diameter before machining thread - target thread pitch diameter) divided by 2 + 0.433 x Thread Pitch - tool nose radius**
(**Where a manufacturer does not use a single nose radius, the manufacturer of the insert may use a flat end with two smaller radii to remove the sharp corners. Don’t use these radii. The manufacturer will specific a distance from the apex of a theoretical 60 degree triangle to the nose of the insert. Use this distance in the above formula.)
Have you ever used thread triangles? I have a set and the work great for V threads. Thoughts?
I've used the "wrong 30 degrees" before. Different lathes have different zero reference points as to where 0 is and where 90 is. I had my compound set to 30 degrees (29 1/2), so I think I'm good to go. I needed to be at 60 1/2 to have the proper angle. Thought I was losing my mind for a while till I figured out what was going on...
Joe, you're the perfect guy for me to ask your opinion of this threading question.
Back in the early 1980's, I went to Wentworth Institute of Technology in Boston.
Great school, I learned a lot.
One thing that they taught was to set the cross slide at 29.5 degrees for cutting external threads.
There was even a special pin with a flat on it that, depending on how you put it into the machine, would add, or subtract .5 degree from the protractor / angle indicator on the cross slide for external or internal threading.
We used various types of standard 60 degree tools to do the cutting.
When I asked our instructor what the .5 degree reduction was for, he said so the tool wouldn't drag on the back side of the thread.
Which didn't make sense to me because you're driving a 60 degree tools sideways at 30 degrees +/- into the stock so it shouldn't drag anyway.
Not wanting my instructor to think I was an idiot, I let it go ( In hindsight I was a kid in school, and should have pressed him for more info ).
What do you think about 29.5 degrees, vs. 30 degrees for the cross slide set up?