Taper Turning without a Compound

[jcdammeyer]

The material is Uddeholm Impax Supreme (P20 Modified) tool steel, hardened to HB 310. 5" diameter, 250rpm.

Wow! My Machinist Toolbox program tells me that Tool Steel H10 (there is no P20 in the list) with HB 325 to 375 has a suggested SFM of 405 when using an carbide insert.

Turning at 250 RPM my calculator tells me that the rate of the surface passing the cutter is 327 SFM.

With a 0.080" depth of cut it tells me 314 RPM and 0.0154 IPR. So I'd guess you aren't quite near the max.

Good show!

 

[thestelster]

Wow! My Machinist Toolbox program tells me that Tool Steel H10 (there is no P20 in the list) with HB 325 to 375 has a suggested SFM of 405 when using an carbide insert.

Turning at 250 RPM my calculator tells me that the rate of the surface passing the cutter is 327 SFM.

With a 0.080" depth of cut it tells me 314 RPM and 0.0154 IPR. So I'd guess you aren't quite near the max.

Good show!

Haha... I had nothing to do with it...lathe and carbide inserts did all the work. I use an app FSWIZARD on my phone for all speeds and feeds, and a ton of other info. I use Sandvik inserts, and their speed recommendation is 2-3x what I used, but probably when using coolant. I don't.