What's new
What's new

Threading stainless steel

82crawler

Plastic
Joined
Mar 10, 2020
Hello all,
I have a question regarding O.D. threads on stainless steel. I am a supervisor for a manual machining department, (production work). We have the need to cut O.D. threads, primarily M6, 8, 10 and 12 often but in small quantities. Most of my machinists are younger and aren't experienced with single point threading. We have tried dies in a holder and by hand as well as auto opening die heads, with mixed results. Any advice on this ? Custom dies with different geometry maybe?
 
You mentioned production but no numbers. If production is 10 or 20 pcs at a time single point threading is the way I would go. Up to a couple of hundred depending on the alloy I might try em with a self-opening die head. The wrong alloy or some other difficulty could eat the chasers and make a nightmare out of it.
Larger quantities i would send them out to have the threads rolled. Git with a thread roller and carefully figure out the blank size needed.
 
I agree with Stephen that a 9/16 Geometric D type (or German equivalent) die head with chasers ground for your material and suitable cutting fluid is the quickest way to get good threads, even with inexperienced operators.

Some manual lathes are not well suited to single point metric threading, even if the operator knows how.

Larry
 
I single point a lot of 304L. It makes a great thread, nice finish etc. but I'd for sure use a quality laydown insert.
Die-cutting SS can be a challenge and die life may not be stellar. At best your young 'uns learn fast, at worst you can pre-cut close with single-point and finish with a die.

I can't comment on the metric factor though. I have the gearing for it but avoid it.
 
All we do is stainless, all the 300 series and 430f. We single point everything. Never had any luck with dies.
I would try my best to teach them how to thread if possible.
 
Then they're not machinists. Single point threading is first year apprentice level.
Rather than try and work around the problem why not teach them how to do it, it'll save you time and money, even in the short term.

>35 years in, and I have yet to ever want to chase threads on a manual lathe ever aggin.
Seldom done it successfully, and have yet to figger out how you stop at the same spot repeatedly - without some sort'a kick-out.
And [unwanted] multi-start threads?

Even if I only have one part to doo, I will opt to stuff it in a CNC lathe to chase OD threads.

I am sure that I could git as good as any of y'all who doo it every day - if I did it every day, but I can still doo a much better job in the CNC than you will, and I can doo it pretty quickly. Got 2 to doo? My second one takes a lot less time than the first!


--------------------

I am Ox and I approve this post!
 
Back in the day,I had a boat repair shop next to me ......anyhoo,he used to replace a whole lot of stainless propshafts .......and .......fill his dumpster with nice stainless steel in handy lengths ..........one thing I discovered is that stainless steel propshaft ranges from 'cuts like butter' all the way to unbelievably tough ......the point being free machining stainless that threads as easily as brass.
 
I've single pointed lots of threads in SS...when they get below 8-32 I usually use a die with a driver and get good results. That's because I can't see well enough to single point stuff that small, reliably. As for the OP's OP....as usual, not enough information provided.
 
>35 years in, and I have yet to ever want to chase threads on a manual lathe ever aggin.
Seldom done it successfully, and have yet to figger out how you stop at the same spot repeatedly - without some sort'a kick-out.
And [unwanted] multi-start threads?

Even if I only have one part to doo, I will opt to stuff it in a CNC lathe to chase OD threads.

I am sure that I could git as good as any of y'all who doo it every day - if I did it every day, but I can still doo a much better job in the CNC than you will, and I can doo it pretty quickly. Got 2 to doo? My second one takes a lot less time than the first!


--------------------

I am Ox and I approve this post!
Yes, I agree but from the OP "I am a supervisor for a manual machining department"
 
The boat guy next to me used to fit all the props with stainless nuts.........if a boat owner tried to undo one ,it would seize tight ,and end up stripping the shaft thread ......yikes!...a new propshaft fitted ..cost about $1000.............I once showed him a nut splitter .........he s like "Are you trying to send me broke"
 
Hello all,
I have a question regarding O.D. threads on stainless steel. I am a supervisor for a manual machining department, (production work). We have the need to cut O.D. threads, primarily M6, 8, 10 and 12 often but in small quantities. Most of my machinists are younger and aren't experienced with single point threading. We have tried dies in a holder and by hand as well as auto opening die heads, with mixed results. Any advice on this ? Custom dies with different geometry maybe?
At the risk of repeating myself. How do you expect to receive help if you don't give all the info.
What stainless?
What inserts?
What machines?
What speed?
What coolant/lubricant?
 
How were you able to hire "machinists" who can't single point thread? That is one of the first things you learn how to do when running a manual lathe. Also, do they know how to measure the threads to see it they cut them correctly or your gonna have another problem.

Now metric threads on a lathe with an inch lead screw makes it more work but still not difficult.
 
If their goal is to become machinist why not spend the time to teach them. So they learn an “advance skill early”. Can you teach 1 or 2 of the more advanced kids. I single point 304 along with 416, both materials cut easily and produced great threads.
 
Last edited:








 
Back
Top