lathe threading limitations question from newbie

[tpic402]

I have been looking for a lathe for a long time and decided that a project (lathe that needs work is out of the question) would a lathe with a TPI (iepm12x36) be limiting for gu work or would a lathe with broader range of threads (ie g4003g) be a wiser choice. if I wait longer and save more dough I could afford other options of lathes. any input appreciated thanks Tom

 

[itsme_Bernie]

Hey Tom

Your question is a little confusing- like you are having a keyboard issue.

But to attempt to address your question, the really rough answer is the more machine you can afford, the most likely you will be to cover your needs.

That said, I would need to see what machine you were comparing the G4003g (TPI eipm12x36?). Is this a PM 12x36?


Bernie

 

[dave2176]

The g4003g is a fine lathe. The thing that pushed it to the top for me was that it will do all american threads 4-112 tpi without changing gears. I don't know if I will need to thread near that high tpi.

The g0750g has the enclosed gear box that i liked, does 4-56 tpi that I thought was sufficient but again changing the change gears for american threads was a turn off. I've been doing a ton of threads and would have to change gearing most days that would really bother my OCD.:jester:

I've heard nothing but good about Precision Matthews and their products, almost bought a mill from them but it was out of stock at the time and the one I bought was supposed to arrive before PM could get one. My bad. Anyway, I would suggest you gather the manuals for the lathes you have in mind and compare them to see the differences between them to help with your selection.

Happy shopping,
Dave

 

[tpic402]

Yes it is a pm 12x36 versus the grizzly g4003g question again. I noticed the grizzly has a much wider thread range than the pm machine. both fall in a resonable price, I did not know what most gun actions use for a barrel thread I have since looked and it seems like either machine would do most actions as far as thread pitch, please correct me if I am wrong.

 

[drs23]

I can't comment on the PM machines other than the owner, Matt, is a member here and highly respected as are his products.

I can comment on the G4003G though as that's the one I purchased and use daily. I'm very impressed with most every aspect and so far it's been trouble free. The only limiting factor is the nut that operates the levers (me). Being as green as I am I've been able to accomplish everything I've attempted to date though it may take more than one attempt. What really sells me on how great of a machine it is is when my Buddy Tom (40 year class A machinist) comes by to give me lessons. That man can "walk the dog" on this lathe! He's very impressed with the accuracy it produces. After we installed the DRO it's even sweeter!

In a word I don't think you can go wrong with either machine. Grizzly's customer service is phenomenal and from what I'm seeing/understanding here Matt's is on top of his game as well.

Pull the trigger on either and my money says you'll be very pleased.

Hope this opinion from the greenest of beans helps.

Dale

 

[tpic402]

Believe me all opinions and comments are of great value every time, and I appreciate the feedback.

 

[epanzella]

Nuther vote for the G4003G. Great machine and no changing gears for American threads.

 

[Ray C]

I think a lot of folks use a 1236 lathe for gunsmith work. It seems many barrels are around 24" or so and that's no problem for 1236. The spindle diameter might be important to you. I don't know about the Griz machines but the PM is 1-9/16" which should be adequate.

Threading: I would not get choked-up over extreme ranges of threading as 56 TPI is about the same thread on the little screws that hold eyeglasses together and you basically need to cut them with a bit not much bigger than a thick sewing needle. I can think of no practical use for threads finer than that and for those who need such threads, they will likely be made on a tiny jeweler's lathe or other specialized threading machine. BTW, threads finer than that are not likely going to be used for fastening purposes but rather for some type of measuring instrument or calibration equipment. The threads on a micrometer thimble shaft are usually 40TPI (or thereabouts) and they are highly precise and cut with lathes far out of the league of any hobby-level machine.

From what I gather, many barrels have fairly coarse threads of around 18 TPI (give or take a little) which is easy territory to work in. I cut such threads on a weekly basis on a manual machine.

Ray

 

[george wilson]

A few lathes will do 19 threads per inch,which is useful if you like using large Remington rolling block actions to build guns around. They use 19 TPI on some of their bolts. I made a 19 TPI tap for a friend who is fond of using those actions.

 

[Ray C]

19 TPI... that's a weird one for the work I do. All the boat shafts are 16, 18 and 20 plus metric usually 1 or 1.25mm/T. Anyhow, I checked and my lathe's gear chart shows 19. I doubt I'll ever use it along with most of the others I did a 36 TPI on a replacement part not too long ago. -Boy, that was easy. 3, maybe 4 passes.


Ray

A few lathes will do 19 threads per inch,which is useful if you like using large Remington rolling block actions to build guns around. They use 19 TPI on some of their bolts. I made a 19 TPI tap for a friend who is fond of using those actions.