*Trying* to turn 316 Stainless...

[PoiToi]

And it is not going well.


Part is out of 10MM 316ss, 3" long, some small RH threads, 1.5" of 10MM LH threads, +/- .001"s all over the damn thing. (it's a fancy ridiculously over-engineered grounding bolt)

How Can I get this material to turn worth a damn? Mostly having trouble with the threading, machine is an old citizen B12 so it only has G92, no fancy G76 for me.
Tried from 100-250SFM for the threading, and from .005 infeed per pass to .010, and any way I go I'm lucky to get 5 parts out of an edge....

The turning is going OK, i got maybe 15 parts out of one edge and and gonna sharpen it a little differently....

Anyone have any tricks for this godawful stuff??

Thanks in advance!

[billz1]

I have ran lots of 316ss with good luck,I run 750 rpm and .002 depth of cut.

[MikeMc]

We run 316 all the time. Good oil and good tooling make it easy. If you are hand making your tools, it is much easier (and cheaper in the long run) to buy inserted tooling made for tough stainless.

[g-code_junkie]

If you are grinding the tools then thread @ 800 rpm and put the allowable flat on the point for the thread you are trying to cut.I put 6 to 8 degrees for clearance on the cutting angles and flat.Also on the B-12 start your threading at -.100 in z and put a dwell of g4u.5 to make sure that your rpm has dropped before threading. For turning I would use the same angle as above along with a radius on the front edge.
Good Luck.

[MMSERV]

I'm running 316 SSTL stems on my Hardinge Conquest ST225B right now. I have found that a full topping, laydown style insert works best. I think mine is Seco. I do not have good results using G96 for threading. I have had good success using G97 around 1200 RPM for a 3/8" 24 pitch thread. I use a pause for at least a half a second between the spindle speed command and starting the treading cycle. If you don't, you run the risk of an inconsistant start if you are starting your thread in the material and moving to the end of the part; not so much of a big deal if you can start 1/4" in front of the part. Use inserts wherever possible unless you are a guru at grinding your own tools. As much as these guys will tell you, you can't be competative grinding your own tools until you have mastered the art. If you want to grind your own tools, setup your job using inserts and practice the art of grinding tools while your machine is making parts with the inserts you bought from you local dealer's stock room.