Good job Mr Pete. I havent needed a multi-start thread in the last 20 years but I'm sure it'll come in handy at some point. I have read about it but never seen it done. Your setup makes it look easy. Thanks
I'm glad you mentioned, at the end, 'for those that will never do this' because I'm one of those and this is valuable to me because I'm learning and understanding how my tools work to make my use of them better. This is why I love your videos. Best Wishes, Brendan.
I work in the valve repair industry and have made numerous stems for gate valves with double lead threads, on some lathes you can split the threads by catching the lead on a number and then half way between the number and the next line. Just thought I would mention this method as an option to try.
THE BEST VIDEO YET. Mr. Pete, you have taken the most complicated lathe operation and broken it down to make it simple. You are on another level when it comes to teaching. America needs more people like you!
As many other viewers i to have to say your explaining on how to do things is remarkably detailed and leaves no space for mistakes. I find it hartwarming to see how you put so much effort and time in putting your tutorials on here Mr pete just as it is equaly hartwarming to see there's still people out there with an incredible amount of craftmanship. Thx ;-)
I do this on a weekly basis. The Ponar lathe I use allows you to 'split' the lead using the thread chasing dial.....makes it pretty easy to cut double lead threads. We also use a large Dean, Smith & Grace to do longer shafts over 32 inches...... You must turn the the chuck 180 degrees when cutting the second thread due to the configuration of the lead screw. But it works well. This was a very good instructional video and like most appreciate your efforts in trying to school manual machinists the proper way to go about making parts and having them actually fit. I believe that manual machining is becoming a lost art....thanx again for your continuing efforts to perpetuate manual maching.
I love watching these videos. I will never cut a double or much less triple. It never really dawned on me how the double thread worked and used it often turning the water on and off. Great information, and learned something new today. Not bad for a guy 77 years old :-) err that's me.
I have cut some normal threads thread at home in the past, but I have never heard of these types. After watching your 2 parts, I don't think I would have a problem with them. You must have been a great teacher. Thanks for all your fantastic videos.
In my humble opinion, you are an outstanding instructor! And I may, “gladly” affix that you haven’t lost any of your salt. Whomever you guided over the years were truly lucky students. As always, thanks’ for taking the time to make this video! And I support this site. ~M~ and as a postscript; I have no-previous knowledge of a machinist’s lathe, however, now I have more knowledge than before. Thanks’ for passing-on your skills and gifts to yet another generation, and I think well beyond!
You needn't worry about unclear explanations. Yours are perfectly clear. As with any subject a complete description of every aspect could fill a half a semester of study. You have covered clearly, what we need to get started and to do the job. Thank you.
I wanted to thank you for your series of instructional videos. Although I have been around machines for all of my life, it is only within the last 10 years that I have begun to understand so many missing things in my machine shop education. Before UA-cam, I was self-taught through many books, trial and error, etc. but your videos helps me to speed up the process of learning and at 63 years of age I need all the speed I can get. :D
Mr. Pete, thanks so much for taking all that time to post your educational videos. It makes me wish that I had been in your shop class, but thanks to the internet, I guess I can. In the above video, you say that multiple start threads are never used for fasteners, but I have found the rare exception. Square D uses four lead screws for the cover plates on their breaker panels.
I ran into another application when a double helix screw was used. It came with a Wen generator that I just purchased. The generator came damaged from the factory and some unscrupulous machinist had included a double helix wheel mounting bolt so that when assembled with a regular nut would make it very difficult to disassemble to return the generator. The average customer would think they had just cross threaded the bolt making it less likely to get returned and very hard to detect. Nobody ever thinks to check if it is a double helix thread.
The trick of using the chuck to drive the dog is very useful. I have been doing this using your first method and having problems getting the spacing exactly precise. I think I will try the chuck method next time. Thankyou for the great tip!
I've seen the multiple thread starts on containers but t didn't associate them to multiple threads...Thank you for the information and clarifying their purpose and their function...they are a very useful threading...Kids wouldn't' t put the milk cap back on the container if they were single thread! I too would like to see the multi-thread for a cap. Thank you again for the great lesson.
I hope to never need to cut a complicated thread like this but I sure did enjoy this video and your explanations were the clearest i have seen. Thank you for your time and effort.
This helps so much. I have to recreate two, two foot long tri-acme thread bars for my friends camper because parts are discontinued. With out them they can't cant sell it. Now I can make them.
Now I know why my father, the Tool and Die Man, was so specific and careful. I also see that operations can be very Exciting! He was that too, excitable. I suppose it was born of the chance of failure on the thin edge of accuracy. Thanks Mr. Pete.
great video good explanations. I hate to say it but I've been a tool maker for thirty years and never cut a double lead thread. I think its like cutting gears just not something we as tool makers do on an every day basis as opposed to seventy five years ago when you couldn't just purchase any gear or special item. You can always learn something new has been one of my mottos through my career. I will retire someday thinking somebody even an apprentice might have an idea I never thought of. T
Gr8 Video Tubalcain, !!! as usual a gr8 explanation of a complex and often misunderstood or inadequately understood process. If I keep watching your videos someone may cause me of understanding what I am talking about .
That took some of the why out of multiple lead threads. The Okuma engine lathe at the shop I work at has another method of cutting multiple lead threads. I will try to upload a video response showing the method of indexing the work. Thanks for all of your videos. I have learned a few things from you, you sure know your way around a shop.
Great stuff, brought back memories of serving my apprenticeship forty five years ago and being hypnotised/cross eyed doing this. Also reminded me of the time a fellow apprentice who having mounted a four jaw chuck in a three jaw (too lazy to swap 'em) was caught by the instructor. Wow! his feet never touched the ground!
My father used to call the two thread start British threads. It is easier to understand now what he was talking about. Thank you for the explanation of this.
You did a great job explaining. I made a triple lead left hand nut for a camper( to raise it) any way it was interesting. Ruined the first one- second one came out great. I had the compound straight with an indicator to pick up my leads
Sir, thank you so much for this (and your others). I chuckled at the end when you said you "hope this clears things up for those who will never do it" as that is me exactly. I greatly appreciate you taking the time to explain things to those of us who use, but will never do, but want to better understand. Your time and efforts are appreciated!
This was very helpful, Professor recommended watching it to better understand the Power Screws we will be designing in an ME machine design course. Thanks!
Great Video Me Pete. Would just like to point out that, when cleaning up the thread to fit the nut you will have to clean up both threads, (most likely). For people asking to show an internal multi start thread, It's just the same set up as for external.
I've always done the plunge cutting... it's how I was taught. But now I'll try the 29' cutting... I believe it will make a smoother, more accurate cut. Thanks, Jerry
As always, Mr. Pete, I do enjoy your videos quite a lot. But, I´d rather make a comment on this last ones: globe valves, are not cheap replacement of gate valves. They´ve got a completely different function: gate valves only open or close, while globe valves can regulate the flow of the fluid. It´s true that even when they´re fully opened, they pose a restriction to the flow, but that´s the price you´ve got to pay if you need flow control.
I will expound on turning a chuck dead center. Its cheap its fast and is your best friend. As said just dont take it out. This is the way I was taught to do this. Dogs, we use anything from hose clamps, muffler clamps, there is not a lot of load on turning with a makeshift clamp. I think this is the first demo of this, so thanks Lyle, for another exellent vidio for the younger people to keep the dying breed alive. Perhaps some day I shall get a vidio camara and add my many many no math no frill machine skills. My first interesting vidio will be, turning a taper on a shaper, and surface grinding on a shaper. Boring a boat shaft taper on a shaper. Milling on a shaper. How to thread a six inch by 10 foot long on any lathe. we do all the time. Mill machine tricks problem is I have not graduated from 8mm movies yet. hats of to you - got no clue how you flim these perfect vidios. Still livin in the 50's sam
Thanks again Lyle, I do need to make a double or maybe triple start for a worm and tap on the same bar to then also hob a gear for a screw fed ball turning attachment for my lathe, I was wondering about a few things mainly how to accurately index the work 180 or 120 degrees without disconnecting gears, you answered that perfectly thanks, I'll go with the between centres method and also stick with between centres for the hobbing. Mark.
Great video Mr Pete. I haven't needed a multi-start in 20 years but sure it'll come in handy at some point. I have read about the topic but never seen it done. Thanks
I suppose the big advantage of the between centres, drive dog on the jaws method, is, if you have to deepen your threads, you can simply switch between jaws, and take an extra cut on each thread.
in general it will be far more accurate to rotate the dog 180, 120, or 90 degrees. the reason why is because to get the same accuracy you need to divide the angular error, say its one part in 180 off, by the tangent of the lead angle, if you want to do better than moving the cutting tool. basically, if your dog is at 0 and 178 degrees, you would need to position the cutting tool for the second start to better than one part in 180 for a 2 start screw with a lead angle of 30 degrees. for a lead angle of 15 degrees, the tool would need to be positioned better than one part in 360!, which might be rather difficult. another option would be to find a tap with the same teeth per inch and stick it into the boring bar holder and cut all the teeth at the same time...
thanks for the video.....I haven't cut a double start acme since 1981 and I might get to cut some in a few weeks on a manual lathe : ) Don Bosco Technical Institute class of 1980
Thank you so much for posting this. I have been trying to figure out how to make a soda bottle cap thread to use a pop bottle as a tank for something. This will help greatly. Thanks!!
Thank you very much for you excellent videos. I enjoy watching them very much. In this particular case an alternative method based on the non parallel compound rest setup (as demonstrated in the second half of part 2 of your video) comes to my mind. For simplicity I will use 30 degrees. You can still use your compound-feed to get the parallel travel towards the chuck as follows: advance the compound rest by the desired distance (in your example 0.084) divided by the sine of 30 degrees, i.e. in this example 0.084 / sin(30) = 0.084 / 0.5 = 0.168. Naturally this would also bring the tool too close to the work. You could compensate for this using the cross feed (naturally). This can be done by finding the point where the tool just touches the work. Or you could calculate the amount of cross feed as compound-feed * cosine of 30 degrees, i.e in your example 0.168 * cos(30) = 0.168 * 0.866 = 0.145 So you have to retract your cross feed by 0.145. To be honest: I never tried this method, but it should work.
When my son was in middle school, he made a lamp from a large bottle that had a plastic cap. I made a new one out of brass. Hardest thread that I ever made. 3 lead 3pitch internal. I had to make two to get one good one.
the atlas book has some good info on this as well. they say this thread can be cut by using the threading dial only by cutting the second thread between marks.
Thank you for the video, as always explained very well to anyone who is interested in machining. I’m one of those people that sometimes love’s to hate design engineer’s. (What were they thinking) But you often explain much of the mystery, the rhyme and the reason behind thing’s !!!
Crystal clear as usual Mr Pete. I still haven't finished rebuilding my old lathe yet and I haven't operated one in nearly 50 years but watching your lessons has given me plenty of confidence , can't wait to start making swarf, or do you say chips? Many thank's
I had the front flush with the jaws, scribed a line down the side of the one jaw rotated the line to two then three. Getting the thread form right was tough too. It isn't in the handbook.
Brilliant as always! Nice idea about using the four-jaw for multiple-start threading. This should set the beginning of the other threads accurate to within fractions of a thou, shouldn't it. I have two large helical focusers for a telescope to make: I'll try it out on this project. Keep up the good work!
Sir, thank you. A year or so ago, when I first started seeing your videos, I was wondering how multi-threaded parts were cut on the lathe. You have now come up with this video series to answer my question! :) Thanks a lot, Mr. Pete. I was thinking to myself that the numbers on the threading dial had something to do with that. Guess I should investigate further into it. Once more, THANK YOU! :) Looking forward for your next videos.
Great video as always. Really appreciate the time you take to educate us out here. Off the subject could you make a video on how to properly use a Carriage Stop. I would think it would me moved out of place once the carriage hits it? Thanks.
Thank You for these two videos. A question, would the depth of cut be half again for each consecutive cut, IE 3 or 4 threads? Yes, I could look it up but I have been spoiled. I appreciate you and have learned much in my old age from you.
Thanks Mr Pete that was my last job at trade school this year. I had to do a 2 start internal then a external on the end of a double throw crankshaft between centres. I like the method of indexing with the chuck as that's where I think I made a mistake with the external thread. Could you also do a video on an internal multi start threads please.
Mr Pete, As always thanks for taking the time to share your knowledge with us. I do have a question though. Why would a guy double cut these treads? Can you get it all in one set up or is it the lathe that doesn't have a setting for it to be done in one go? Thanks, Mike
I want to try making one. With CNC lathe it wuold be too easy if I understood the methods right. Just to make it overkill I'd do 10 start. -CNC-machinist from Finland
i know this is a rather advanced vid to ask this on but, i was wondering if you have any suggestions on how to get started what into lathes etc would be a good fit for the largest amount or rather as i like to say when building computers since 95' "future proof" thanks for info regardless i have just always wanted to get into such amazing craftsmanship and always assumed it was simply out of reach both in price and knowledge
I'm late to the party but.. couldn't you just use a little trig to figure out how far to move the compound in? You'd need to back up the cross feed for clearance. I could see where on internal threads, on an irregular shaped part, that would be advantageous to those people that set the compound to 29-30 degrees. Also, unless the angle on your tool and the angle set on the compound are exactly the same, the tool will be cutting on both faces anyway. If you have a light lathe you may benefit from a perfect setup but you should get the same result by just taking less deep cuts using the plunge method. Thanks again for the excellent video.
How does this work?. every time you just only move the carriage without reversing the spindle am a little confused if you or anyone could explain please
Thanks I learned a lot. You know the orange juice container that you showed? I think it had a 4 start tread, could you do a video showing how to make a aluminum cap For that? I would really like to see how it would be done. A alum cap with internal threads that's short and is 1/4 turn on and off.
I would imagine that you would have to turn that on the "wrong side" and start form within the nut and move the tool back to the right, but i agree, it would be interessting to see how its done properly
Yes the thread on the nut has to be cut twice also. They did mention it, a special tap needs to be used (a double thread tap!) or a boring bar for larger internal diameters but it is not for the faint of heart he said.
No disrespect whatsoever Mr Peterson but if keeping the compound at 29deg (today with trig calculators in your top pocket), might not it be easier to draw on the white board just what are the triangle ratios when the compound advances 1Unit? At 29deg, the triangle becomes hyp=1 Opp=.4848 Adj=.8746. With staying at 29deg and with a little practice, we can know the exact position of the tool tip once it has been zeroed initially, and with only the advance of the compound. Its just a thought. I'd prefer to work this way rather than taking sideways measures. I'd get the precise (no backlash) pitch and work the tool tip N/S, E/W on the ratio against 1 especially when doing small stuff like this.
Seems that the cast drive plate wouldn't be out of tolerance any more than your dial indicator that wasn't perpendicular when you took your measurement. Perhaps for this application these threads generally have enough slop that that minute amount won't hurt things. Yes/No? I missed the point of why you plunge cut these instead of feeding with the angled compound. I realize there would be a little more math to indicate the tool start position. Back or advance the compound so the tool moves half the lead, advance with the cross slide, touch off and re-zero. Would that work? I'll watch it again. Great segment!
Great instructional video, but the double thread really screws with my head. It would appear that as long as the tpi is the same the speed which the thread advances in a nut would be the same. That part I am not getting at all. But thanks for the video.
Your years of teaching experience are evident in your presentation. Loved seeing the alternative ways of cutting multi-start threads.
Thank you very much
Good job Mr Pete. I havent needed a multi-start thread in the last 20 years but I'm sure it'll come in handy at some point.
I have read about it but never seen it done. Your setup makes it look easy. Thanks
I'm glad you mentioned, at the end, 'for those that will never do this' because I'm one of those and this is valuable to me because I'm learning and understanding how my tools work to make my use of them better. This is why I love your videos.
Best Wishes, Brendan.
Thank you
I work in the valve repair industry and have made numerous stems for gate valves with double lead threads, on some lathes you can split the threads by catching the lead on a number and then half way between the number and the next line. Just thought I would mention this method as an option to try.
THE BEST VIDEO YET. Mr. Pete, you have taken the most complicated lathe operation and broken it down to make it simple. You are on another level when it comes to teaching. America needs more people like you!
Thank you very very much. It’s 7 o’clock in the morning and you already made my day.
As many other viewers i to have to say your explaining on how to do things is remarkably detailed and leaves no space for mistakes.
I find it hartwarming to see how you put so much effort and time in putting your tutorials on here Mr pete just as it is equaly hartwarming to see there's still people out there with an incredible amount of craftmanship.
Thx ;-)
Instructional videos don't get any better than this. Excellent!
What a master teacher, god bless you Mr. Pete.
Thanks
I do this on a weekly basis. The Ponar lathe I use allows you to 'split' the lead using the thread chasing dial.....makes it pretty easy to cut double lead threads. We also use a large Dean, Smith & Grace to do longer shafts over 32 inches...... You must turn the the chuck 180 degrees when cutting the second thread due to the configuration of the lead screw. But it works well. This was a very good instructional video and like most appreciate your efforts in trying to school manual machinists the proper way to go about making parts and having them actually fit. I believe that manual machining is becoming a lost art....thanx again for your continuing efforts to perpetuate manual maching.
I love watching these videos. I will never cut a double or much less triple. It never really dawned on me how the double thread worked and used it often turning the water on and off. Great information, and learned something new today. Not bad for a guy 77 years old :-) err that's me.
Kenneth Bartlett Thanks for watching--its an interesting concept. I'm about to turn 72
I have cut some normal threads thread at home in the past, but I have never heard of these types. After watching your 2 parts, I don't think I would have a problem with them. You must have been a great teacher. Thanks for all your fantastic videos.
In my humble opinion, you are an outstanding instructor! And I may, “gladly” affix that you haven’t lost any of your salt. Whomever you guided over the years were truly lucky students. As always, thanks’ for taking the time to make this video! And I support this site. ~M~ and as a postscript; I have no-previous knowledge of a machinist’s lathe, however, now I have more knowledge than before. Thanks’ for passing-on your skills and gifts to yet another generation, and I think well beyond!
Thank you
You're the best, Lyle.
Can you please do a series on creating mating thread sets that are both left hand and right hand threads. Thanks for what you do.
You needn't worry about unclear explanations. Yours are perfectly clear. As with any subject a complete description of every aspect could fill a half a semester of study. You have covered clearly, what we need to get started and to do the job. Thank you.
I may not ever cut a double thread but I sure did learn how to check if my 3 jaw chuck is good. You always teach me something. Thanks
I wanted to thank you for your series of instructional videos. Although I have been around machines for all of my life, it is only within the last 10 years that I have begun to understand so many missing things in my machine shop education. Before UA-cam, I was self-taught through many books, trial and error, etc. but your videos helps me to speed up the process of learning and at 63 years of age I need all the speed I can get. :D
Dan Butterworth, It looks as though one of the things missing from your machine shop education was a safety face shield. What happened to you? =0
:)
Mr. Pete, thanks so much for taking all that time to post your educational videos. It makes me wish that I had been in your shop class, but thanks to the internet, I guess I can. In the above video, you say that multiple start threads are never used for fasteners, but I have found the rare exception. Square D uses four lead screws for the cover plates on their breaker panels.
Thank you, yes I have seen those fasteners
I ran into another application when a double helix screw was used. It came with a Wen generator that I just purchased. The generator came damaged from the factory and some unscrupulous machinist had included a double helix wheel mounting bolt so that when assembled with a regular nut would make it very difficult to disassemble to return the generator. The average customer would think they had just cross threaded the bolt making it less likely to get returned and very hard to detect. Nobody ever thinks to check if it is a double helix thread.
You're the best. I've learnt a lot from you. Your channel is amazing. Thanks
Thank you very much
Excellent video Mr. Pete! As usual your demonstrations are superb! A lot of good setup ideas there too!
The trick of using the chuck to drive the dog is very useful. I have been doing this using your first method and having problems getting the spacing exactly precise. I think I will try the chuck method next time. Thankyou for the great tip!
I've seen the multiple thread starts on containers but t didn't associate them to multiple threads...Thank you for the information and clarifying their purpose and their function...they are a very useful threading...Kids wouldn't' t put the milk cap back on the container if they were single thread! I too would like to see the multi-thread for a cap. Thank you again for the great lesson.
+sammy mezzacapo THANKS for watching--much more to come
Thank you for explaining this so clearly and easily!
I hope to never need to cut a complicated thread like this but I sure did enjoy this video and your explanations were the clearest i have seen. Thank you for your time and effort.
This helps so much. I have to recreate two, two foot long tri-acme thread bars for my friends camper because parts are discontinued. With out them they can't cant sell it. Now I can make them.
👍
Now I know why my father, the Tool and Die Man, was so specific and careful. I also see that operations can be very Exciting! He was that too, excitable. I suppose it was born of the chance of failure on the thin edge of accuracy. Thanks Mr. Pete.
great video good explanations. I hate to say it but I've been a tool maker for thirty years and never cut a double lead thread. I think its like cutting gears just not something we as tool makers do on an every day basis as opposed to seventy five years ago when you couldn't just purchase any gear or special item. You can always learn something new has been one of my mottos through my career. I will retire someday thinking somebody even an apprentice might have an idea I never thought of. T
Gr8 Video Tubalcain, !!! as usual a gr8 explanation of a complex and often misunderstood or inadequately understood process. If I keep watching your videos someone may cause me of understanding what I am talking about
.
THANKS--keep watching
That took some of the why out of multiple lead threads. The Okuma engine lathe at the shop I work at has another method of cutting multiple lead threads. I will try to upload a video response showing the method of indexing the work.
Thanks for all of your videos. I have learned a few things from you, you sure know your way around a shop.
Mr. Pete, yuor channel is a golden miner, you are a great teacher!! Antonio (Rome, Italy)
Thank you
I once spent a great deal of money for a quad tap and die because I could not figure out how to do what you have just explained so clearly. Thanks!
+William Lee Thanks for watching-I did not know they sold such taps & dies
+mrpete222 They were custom ground.
Excellent explanation Mr. Pete! I'm going to give it a shot cutting both the nut and double lead screw this weekend.
+John Pullen THANKS for watching--much more to come
Excellent tutorial. Even us old shop guys can learn a thing or two. Thanks!
Thank you for this patient teach in.It was very helpful for me.Thanks for your kindness.
Great stuff, brought back memories of serving my apprenticeship forty five years ago and being hypnotised/cross eyed doing this. Also reminded me of the time a fellow apprentice who having mounted a four jaw chuck in a three jaw (too lazy to swap 'em) was caught by the instructor. Wow! his feet never touched the ground!
My father used to call the two thread start British threads. It is easier to understand now what he was talking about. Thank you for the explanation of this.
You did a great job explaining. I made a triple lead left hand nut for a camper( to raise it) any way it was interesting. Ruined the first one- second one came out great. I had the compound straight with an indicator to pick up my leads
Great explanation. Thanks a lot for your Videos.
Sir, thank you so much for this (and your others). I chuckled at the end when you said you "hope this clears things up for those who will never do it" as that is me exactly. I greatly appreciate you taking the time to explain things to those of us who use, but will never do, but want to better understand. Your time and efforts are appreciated!
This was very helpful, Professor recommended watching it to better understand the Power Screws we will be designing in an ME machine design course. Thanks!
Glad it helped
Great Video Me Pete.
Would just like to point out that, when cleaning up the thread to fit the nut you will have to clean up both threads, (most likely).
For people asking to show an internal multi start thread, It's just the same set up as for external.
+john irons Thanks for watching
Mr Pete thank you for all the training and tips you have posted, it has helped me out with a good amount of non common practice day to day machining!
I've always done the plunge cutting... it's how I was taught. But now I'll try the 29' cutting... I believe it will make a smoother, more accurate cut.
Thanks,
Jerry
As always, Mr. Pete, I do enjoy your videos quite a lot.
But, I´d rather make a comment on this last ones: globe valves, are not cheap replacement of gate valves. They´ve got a completely different function: gate valves only open or close, while globe valves can regulate the flow of the fluid. It´s true that even when they´re fully opened, they pose a restriction to the flow, but that´s the price you´ve got to pay if you need flow control.
I will expound on turning a chuck dead center. Its cheap its fast and is your best
friend. As said just dont take it out. This is the way I was taught to do this. Dogs,
we use anything from hose clamps, muffler clamps, there is not a lot of load on
turning with a makeshift clamp. I think this is the first demo of this, so thanks Lyle,
for another exellent vidio for the younger people to keep the dying breed alive.
Perhaps some day I shall get a vidio camara and add my many many no math
no frill machine skills. My first interesting vidio will be, turning a taper on a shaper,
and surface grinding on a shaper. Boring a boat shaft taper on a shaper. Milling on
a shaper. How to thread a six inch by 10 foot long on any lathe. we do all the time.
Mill machine tricks problem is I have not graduated from 8mm movies yet.
hats of to you - got no clue how you flim these perfect vidios.
Still livin in the 50's sam
Thanks again Lyle, I do need to make a double or maybe triple start for a worm and tap on the same bar to then also hob a gear for a screw fed ball turning attachment for my lathe, I was wondering about a few things mainly how to accurately index the work 180 or 120 degrees without disconnecting gears, you answered that perfectly thanks, I'll go with the between centres method and also stick with between centres for the hobbing.
Mark.
You bring me back to a great time in my life,Shop Class thank you
👍
What a incredible teacher. Thank you
+Keith Hansen Thanks for watching
Thank you Mr. Pete, This was very helpful!
Great video Mr Pete. I haven't needed a multi-start in 20 years but sure it'll come in handy at some point.
I have read about the topic but never seen it done. Thanks
I suppose the big advantage of the between centres, drive dog on the jaws method, is, if you have to deepen your threads, you can simply switch between jaws, and take an extra cut on each thread.
in general it will be far more accurate to rotate the dog 180, 120, or 90 degrees.
the reason why is because to get the same accuracy you need to divide the angular error, say its one part in 180 off, by the tangent of the lead angle, if you want to do better than moving the cutting tool.
basically, if your dog is at 0 and 178 degrees, you would need to position the cutting tool for the second start to better than one part in 180 for a 2 start screw with a lead angle of 30 degrees. for a lead angle of 15 degrees, the tool would need to be positioned better than one part in 360!, which might be rather difficult.
another option would be to find a tap with the same teeth per inch and stick it into the boring bar holder and cut all the teeth at the same time...
thanks for the video.....I haven't cut a double start acme since 1981 and I might get to cut some in a few weeks on a manual lathe : )
Don Bosco Technical Institute class of 1980
👍👍
Thank you so much for posting this. I have been trying to figure out how to make a soda bottle cap thread to use a pop bottle as a tank for something. This will help greatly. Thanks!!
Thank you very much for you excellent videos. I enjoy watching them very much.
In this particular case an alternative method based on the non parallel
compound rest setup (as demonstrated in the second half of part 2 of your video)
comes to my mind.
For simplicity I will use 30 degrees.
You can still use your compound-feed to get the parallel travel towards the chuck as follows:
advance the compound rest by the desired distance (in your example
0.084) divided by the sine of 30 degrees, i.e. in this example
0.084 / sin(30) = 0.084 / 0.5 = 0.168.
Naturally this would also bring the tool too close to the work.
You could compensate for this using the cross feed (naturally).
This can be done by finding the point where the tool just touches the work.
Or you could calculate the amount of cross feed as
compound-feed * cosine of 30 degrees, i.e in your example
0.168 * cos(30) = 0.168 * 0.866 = 0.145
So you have to retract your cross feed by 0.145.
To be honest: I never tried this method, but it should work.
Thanks Mr Pete. Very good and clear explanation.
An interesting topic and very good explanations. Thanks
When my son was in middle school, he made a lamp from a large bottle that had a plastic cap. I made a new one out of brass. Hardest thread that I ever made. 3 lead 3pitch internal. I had to make two to get one good one.
+Richard Haisley I bet that was tough
Like always OUTSTANDING this is something I always wondered about how or why it would travel so far with only one turn (like on the gate valve)
the atlas book has some good info on this as well. they say this thread can be cut by using the threading dial only by cutting the second thread between marks.
Nicely done!
Very interesting. Never knew what double threading was useful for.
Very well taught, thank you much.
Thank you for the video, as always explained very well to anyone who is interested in machining. I’m one of those people that sometimes love’s to hate design engineer’s. (What were they thinking) But you often explain much of the mystery, the rhyme and the reason behind thing’s !!!
I saw the scratches in the layout fluid @6:45;) No finger crossing needed
yeah I did saw it too lol. I think mr pete did cross his finger, in hope we do not see it ;)
Shhh.. you weren't supposed to blab.
Eddie the Grouch yup saw them also
Drama!
Thx for showing the different methods.
Crystal clear as usual Mr Pete. I still haven't finished rebuilding my old lathe yet and I haven't operated one in nearly 50 years but watching your lessons has given me plenty of confidence , can't wait to start making swarf, or do you say chips? Many thank's
I had the front flush with the jaws, scribed a line down the side of the one jaw rotated the line to two then three. Getting the thread form right was tough too. It isn't in the handbook.
Another excellent video!!!
Brilliant as always!
Nice idea about using the four-jaw for multiple-start threading.
This should set the beginning of the other threads accurate to within fractions of a thou, shouldn't it.
I have two large helical focusers for a telescope to make: I'll try it out on this project.
Keep up the good work!
hey Pete, thank you for sharing this video, tomorrow I am getting to cut a 6 lead thread
Sir, thank you. A year or so ago, when I first started seeing your videos, I was wondering how multi-threaded parts were cut on the lathe. You have now come up with this video series to answer my question! :) Thanks a lot, Mr. Pete. I was thinking to myself that the numbers on the threading dial had something to do with that. Guess I should investigate further into it. Once more, THANK YOU! :) Looking forward for your next videos.
Very interesting and helpful. Have a nice Christmas. So long and thank you.
To answer my own question, I think the answer is yes because of the room required for the extra threads. Me, slow but somewhat sure!!
Great video as always. Really appreciate the time you take to educate us out here. Off the subject could you make a video on how to properly use a Carriage Stop. I would think it would me moved out of place once the carriage hits it? Thanks.
Thank You for these two videos. A question, would the depth of cut be half again for each consecutive cut, IE 3 or 4 threads? Yes, I could look it up but I have been spoiled. I appreciate you and have learned much in my old age from you.
Thanks Mr Pete that was my last job at trade school this year. I had to do a 2 start internal then a external on the end of a double throw crankshaft between centres. I like the method of indexing with the chuck as that's where I think I made a mistake with the external thread. Could you also do a video on an internal multi start threads please.
That's a great way of cutting double start
Thanks
Fantastic vid! Thank you!
Great video, as usually. I really like your teaching method.
Mr Pete,
As always thanks for taking the time to share your knowledge with us. I do have a question though. Why would a guy double cut these treads? Can you get it all in one set up or is it the lathe that doesn't have a setting for it to be done in one go?
Thanks,
Mike
Not sure if everyone realizes it, but the nut must also be a multi-start to match the screw.
Yes---of course
Unless you're the infamous Hammer and Chisel mechanic, he just makes it fit with a bigger wrench.
very good videos! when you needed to take another pass to make it fit i noticed you paused! what thread needed another pass!? LOL
That was great Mr, Pete,
Will you show us how to do a timed thread next please?
Jim
Thanks for this video. I learn so much from your videos.
Thanks mrpete, I'm sure I will end up using this some time. I'm always repairing something.
I want to try making one. With CNC lathe it wuold be too easy if I understood the methods right. Just to make it overkill I'd do 10 start.
-CNC-machinist from Finland
Great lesson..thank you, going to give it a try....Happy Holidays to you and your family
+outsidescrewball THANKS for watching--much more to come
Nice! Great video, thanks 🎄😊🎄.
Thanks
i know this is a rather advanced vid to ask this on but, i was wondering if you have any suggestions on how to get started what into lathes etc would be a good fit for the largest amount or rather as i like to say when building computers since 95' "future proof" thanks for info regardless i have just always wanted to get into such amazing craftsmanship and always assumed it was simply out of reach both in price and knowledge
I'm late to the party but.. couldn't you just use a little trig to figure out how far to move the compound in? You'd need to back up the cross feed for clearance. I could see where on internal threads, on an irregular shaped part, that would be advantageous to those people that set the compound to 29-30 degrees. Also, unless the angle on your tool and the angle set on the compound are exactly the same, the tool will be cutting on both faces anyway. If you have a light lathe you may benefit from a perfect setup but you should get the same result by just taking less deep cuts using the plunge method. Thanks again for the excellent video.
Sure you could
Very nice how its made series .
+danny krumpton THANKS for watching--much more to come
How does this work?. every time you just only move the carriage without reversing the spindle am a little confused if you or anyone could explain please
Thank you for all these interesting, educational and helpful videos.
Merry Christmas
George
What are your thoughts on Thread in two directions?
Thanks I learned a lot. You know the orange juice container that you showed? I think it had a 4 start tread, could you do a video showing how to make a aluminum cap For that? I would really like to see how it would be done. A alum cap with internal threads that's short and is 1/4 turn on and off.
I would imagine that you would have to turn that on the "wrong side" and start form within the nut and move the tool back to the right, but i agree, it would be interessting to see how its done properly
or perhaps turn the chuck by hand...that would probably be easier and quicker...
I missed if you said this..But is the internal thread also double cut? Seems like is should be.
Yes the thread on the nut has to be cut twice also. They did mention it, a special tap needs to be used (a double thread tap!) or a boring bar for larger internal diameters but it is not for the faint of heart he said.
Awesome explanation Sr. Exactly the info that I was looking for. Cheers from Argentina!
Hi, now how about showing us how to make multiple lead nuts?
No disrespect whatsoever Mr Peterson but if keeping the compound at 29deg (today with trig calculators in your top pocket), might not it be easier to draw on the white board just what are the triangle ratios when the compound advances 1Unit? At 29deg, the triangle becomes hyp=1 Opp=.4848 Adj=.8746. With staying at 29deg and with a little practice, we can know the exact position of the tool tip once it has been zeroed initially, and with only the advance of the compound. Its just a thought. I'd prefer to work this way rather than taking sideways measures. I'd get the precise (no backlash) pitch and work the tool tip N/S, E/W on the ratio against 1 especially when doing small stuff like this.
Seems that the cast drive plate wouldn't be out of tolerance any more than your dial indicator that wasn't perpendicular when you took your measurement. Perhaps for this application these threads generally have enough slop that that minute amount won't hurt things. Yes/No? I missed the point of why you plunge cut these instead of feeding with the angled compound. I realize there would be a little more math to indicate the tool start position. Back or advance the compound so the tool moves half the lead, advance with the cross slide, touch off and re-zero. Would that work? I'll watch it again. Great segment!
+blmeflmm66 THANKS for watching--much more to come
Great! Keep up the great work!
Great instructional video, but the double thread really screws with my head. It would appear that as long as the tpi is the same the speed which the thread advances in a nut would be the same. That part I am not getting at all. But thanks for the video.
👍