Rolling Threads

[topcatproduction]

Hi there. I hope this is in the right section, whilst having been involved in engineering since school (I am now 25) I was never majorly involved in precision engineering, hence the questions.

I am looking to make some 7/16 studs from EN24, they are different lengths but roughly between 3" and 4" long, with over an inch of thread on each end, UNC and UNF.

Basically, what machinery would I be best to use, I have a manual Colchester Triumph lathe in the workshop but as I will be after a quantity of a hundred or so at a time I believe it would not be efficient to consider using it.

All options and opinions welcome!

p.s. they will also be heat treated to V grade, though I need to do my research on hardnesses etc as I am very green to it.

 

[bithkits]

Give kinefac a shout, they might be able to assist you with ideas

http://www.kinefac.com/

Adriaan.
I am an Engineer/part time student (Mechatronics) from South Africa.
Advice from lecturer: "Be warned - when you go into industry your boss will give you a thousand things to do and he wants them done yesterday!" So far he is right...

 

[TVP]

For a relatively small quantity (lot size ~ 100), the blank will be produced almost certainly by some type of metal cutting machine (CNC turret lathe, manual lathe, etc.). Depending on the desired dimensional accuracy, surface roughness, mechanical properties, etc., it may need two additional secondary operations: grinding of the body/shank and thread rolling of the ends. If you intend to have the parts machined in the quenched & tempered condition, then thread rolling is really the better option, and a Kinefac machine is one of the best available. Have you contacted any contract machine shops in your area, perhaps one that specializes in prototyping automotive parts?

 

[topcatproduction]

Thanks for the replies, I have had a price for making up a quantity, but it was too expensive when compared to other available products that would do the job.

Just had a look at the kinefac website and it is most impressive! What would the likelihood be of finding a used machine for rolling the threads myself, and what should I look for? I know I won't be able to afford full cnc, manual is fine as long as setup time is minimal between operations.

 

[tbuelna]

topcatproduction,

For 100 pcs:

1. Purchase 100+ pcs of heat treated EN24 cond. V (145 ksi) cold-rolled 7/16" bar stock cut to length.
2. Machine the stud blanks yourself on your lathe with the correct end diameters needed for thread rolling. 145ksi steel is still soft enough to thread roll.
3. Send the 100 blanks (plus a few spares) to your local thread roller.

Good luck.
Terry

 

[topcatproduction]

I'm considering buying a cnc turret lathe, not just for these as I do a fair bit of lathe work and would be handy and increase production. This way I should be able to turn the bars down and roll the first thread with a thread rolling head, then will it be a case of modifying some chuck jaws so they only grip the smooth between the threads and rolling the other end?

 

[topcatproduction]

Also where can I find data on what diameters to turn bar down to before rolling threads? They will be 7/16 UNC and UNF, 14tpi and 20tpi respectively.

 

[TVP]

This link has some information on thread rolling including pre-roll blank sizes:

http://www.landisthreadingsystems.com/ThreadRolling/Library/TechnicalSupport.pdf

 

[topcatproduction]

Another great link thankyou ;-)