Stainless Steel ?

[Depoman]

I have to machine a 1/8 rad on a 1/4"x1-1/4"x800 hundred feet total (various lengths)
I plan to use a 4 flute carbide radius cutter (concave) with an OD of .75 inch
My resources say 1250 RPM at 10 in/min.

This sound right to all of you Stainless gurus?

I have little experience with stainless and if I can save a cutter or 2 it would be appreciated.

Thanks

[HuFlungDung]

If you've got flood coolant, I would recommend roughing using a high speed steel cutter. But that's just me. There may be good results possible with the correct coating on carbide, but for sure, not just any coating will do. The keen edge of HSS is not to be scorned when cutting soft stainless in the 300 series.

But, I certainly will not call myself an expert in stainless, so if anyone else wants to contradict what I said, feel free. I'm just relating my experience. I want to believe that carbides can be used for it too...just not sure which one will last long enough to be economical.

[bonz]

What type of stainless is it?

It sounds like you are around the low end for soft stainless (303, 304).

For soft stainless grades, I would run between 1250-2000 rpm and 10-16 ipm. Slower doesn't always get you better tool life... watch your chips. Also, you may be able to push your chip load up to .003 per tooth (15-24 ipm). It depends on how well the radius was put on the tool.

One last suggestion, get your tools coated with TiCN. This coating has a very low coefficient of friction which will greatly reduce galling and material buildup at the cut edge. It will also improve tool life.

Good Luck,
Bonz