MACHINE SHOP TIPS #18 Musing on Lathe Threading tubalcain

[swallin19]

On the permanent engagement this is widely taught in Europe and some lathes have no dial fitted, tool retraction, or lift, is used during reverse to clear the thread. Rarely done by Home Machinists is single point chasing, delightfully controllable method for ultra fine finish, and any pitch can be cut if you have a master. We were instrument makers and used a 4:1 masters and made custom fit threads, no tolerance, they were made to feel right on assembly for focussing threads in lenses.

[swallin19]

Sometimes it is obvious a method works, without realizing that other countries do it another way, British machinists had never been shown this method before the war!! South Bend were one of the rare makers who published methods, and taught the US way of cutting threads with set over.

UK method is straight plunge, both faces cut in traditional method. The end result is the same as at full depth both sides touch. In Swiss precision practice straight is used, as Chasing is more widely used.

[BMWHP2]

Perfect explenation, good teacher and nice instruction video,

Thanks a lot Sir

[gmcallsuk]

Superb videos, I feel very nostalgic whilst watching them, as these are the exact methods to thread on the lathe shown to me my my mentor 30 years ago when I was an apprentice. The guy I learned with has sadly passed on and I really miss him. Oddly enough I feel he is still not too far away watching over my shoulder me complete all the the tasks him and myself did all them years ago. Still learned a little tip using the blue as we just used a nut to test when coming down to the money on size.

[WalneySkyland]

Don't just slam the gearbox into reverse... have the cross slide set to zero all the time and as you get to the end of the cut wind out at hte same time you declutch then reverse it and before you put the next cut onto the compound simply remember to wind the cross slide back in to zero and carry on as you would normally. Given sufficient practice it becomes as much second nature as any other method I was quite shocked when you just slammed it into reverse like that.

[par4par72]

Take it from someone who used to single point 0-80 coiling mandrels for Heli-Coil. this is proper technique and optimal. you can NOT SP thread 0-80x3" using any other method and hold .0002!!! END OF STORY!

[dirtyharry793]

Thanks again for a great lesson. The more I watch, the more I am inspired to learn!

[SeriousSpeedtrash]

im not sure how long its going to take me to get through all these videos but im sure i will, and ill try to remember to "like" each one! thanks for being a great teacher!

[makedoandmend2]

Could you please put a video on giving us some tips on using a fixed steady and a traveling steady.

[rastah76]

loving your videos. Do you have it all on a dvd?

[kikilosabeyno]

I used to do it without the angle (my teacher didn't said me to do that) and never broke a tool bit, but the threads finished with a terrible finishing, now I'm doing it with the 29° angle, it leaves a better finish and it takes longer to the tool bit to get dull.

[JeJeanSansterre]

Thanks again, Great HD

[terrywerm]

I learned machine shop practice from a very good high school shop teacher, who, like you, was what I call a 'true teacher'. 'True teachers' are those who take the time to teach simply because there are those who wish to learn from them. You take so much time from your retired life to continue teaching those who wish to learn, and you are a true credit to your profession. Your videos have been great refreshers as I have gotten into hobby machining. Keep up the great work, it is much appreciated!

[mrpete222]

@terrywerm Thanks for your very great encouragement!!!!

[jrolands]

I'm not sure if anyone else have commented on this, but if you retract the cross slide using the same method as when you disengage the 1/2-nut you will not have the problem of the tool dulling and the thread ruined because of the backlash in the carriage. I'm currently studying metal work in Norway, and they don't teach using the thread dial at all. They don't even mention it, which I think is a shame cause of the time saved and all the other excellent points you make.

Great videos! Thanks! :D

[ShaiHulud1982]

I agree with you 100% about not reversing the feed, However I have chased metric threads on a Leblond and that was the only way to accomplish it. I'm not sure If I would have to do this process on all lathes, but I believe it has something to do with the lead screw being standard inch threads and chasing metric. an acme thread video would be Great! Just made a replacement shaft for an airplane engine fixture with Metric acme threads.

[refa42]

@mrpete222

Acme threads sounds great. But after this one I would rather see bunch of clips in series of you doing stuff in or outside the shop that you enjoy doing. Without the teaching part. That's because of long row of detailed videos and now this serious business of processing feedback that you shouldn't have received in the first place.

[sandwon]

Thank You for taking time to make these Threading Video's

Thanks for sharing your Knowledge,I watch all your Video's.

My next Project is 4 Thread per Inch x 1.375 inch ACME Thread

Can you tell me what Type of bit to cut the threads ??

Thanks

[lasttry666666]

ill be waiting for the next vids . been wondering how acme thread is done .

[kenworth3406e600hp]

Great Video, I served my 5 Year Tool & Die Apprenticeship from 1989 to 1994 at Boeing in Seatlle and your method is they way I was taught by the Old Journeyman.

I have done it exactly like you many times and it worked perfectly every time.

Keep up the great work.

We manual machinists are like dinasours, slowly becoming extinct due to CNC machines.

[GK1918]

Total agreement on reversing thats just more 1/2 nut abuse. I may add when I

have to do a pick up with 1/2 nut engauged I always turn the belt by hand so

there is no backlash, picking up a thread does happen, but I made up a 2cent

cross feed stop no need to be fancy just a washer bolt and lock nut, perfect.!

Now for the great Acme thread thanks

[harleyghost]

Great machining tip, I will remember this one. Also thank you for going into the Acme threading. I can use that one for a future project I have planned. Making a milling attachment for my lathe.

[TheMartorious]

Keep 'em coming. I get something from everyone of your videos, I've watched all your casting and machining videos once, several of them multiple times. This has been a subject I've been interested in learning for quite a while and now I feel I know enough to at least go tool shopping with at least some idea of what features I want and how to evaluate a machine for purchase. Thanks for all you do and all you share!

Marty

[junglejammer]

Don't worry about "beating this to death," these are the details, that we need and are often, glossed over by others. I wish that I had had you for my shop teacher in high school. I admired the man that we had, however, he was a brand new teacher, at the time and needed more experience. Thank you, for sharing your's.

Junglejammer

[cannonball666]

@mrpete222

About keeping the half nut engaged constantly: I understand what you mean by backlash becoming a thread-damaging factor if you reverse the lathe. However, that is only the case if you don't back the cutter off completely before reversing.

[alexanderkm11]

I can not agree more with the video and your logic. But in defense of those who chose to revers the lathe, they still withdrawal the compound when they reach the end of the thread, then rewind. The advantage is that you can avoid waiting for the threading dial to come around. However this is not always favorable with a long thread, say for example you were making a 1/2-20 thread 36" long with the lathe at 100 rpm. Tell me do still want to rewind, it will take 7 min and 12 seconds.

[jwsvandr]

Thanks again for a great video. I am looking forward to any and all of your future videos. I would also like to thank you on behalf of all the students who got a sense of wonder and accomplishment from making things with their own hands. I have used what I learned in shop classes more than anything else I learned. Keep on teaching and we will keep on learning (hopefully).

[mrmatt2525able]

this guy knows his stuff on everything on mechanics, dont dout him, he is helpful and cool

[necedm]

Your definitely not boring us with your video's mrpete!! The more the merrier! :)

[mithigarcha1]

i agree with "refa42" ,kids make sure you do your homework before you question a teacher LOL...thanks mr Tubalcain , for another video ,,im waiting for more vids on threading ,more the merrier lol,,,,,,,thanks again

[refa42]

I know that some things are hard to understand but come on people, do some research on your own or at least think it for a second before opening your email and argue the point. Mrpete222 has made his living by teaching this stuff which should tell you that you double check your reasoning before even thinking about emailing. Actually there was two good reasons for doing so in that last sentence.

[outsidescrewball]

Thanks....another lesson learned today on the picking up the thread.....looking forward to the ACME lesson

[bennny12]

you da man

[apowellz]

Another great video.  I am looking froward to your description on cutting an Acme thread.

Thanks.

[zippy308]

Great video because I was wondering how you get back on track. I really like the HD as well. I can't wait for the Acme! Keep up the good work.

[MrDan27611]

Can't wait for the internal threading video. Thanks for all your work.

[jsmith65625]

I wanted to say thanks for this video in particular. The 29deg was taught to us the last few months in Tech School, and while I got it down fine, and made threads with it, I questioned it since you square off the tool to the stock. It didn't dawn on me about the fact the you're feeding the compound in at that angle to cut in that manner. Thanks!

Also, to the people that want to just throw the machine in reverse, it doesn't sound good for a reason. That's a lot of force to instantly turn around.

[ferks60]

Great videos, you are very good teacher !