01-15-2013, 12:36 PM
(01-15-2013, 10:40 AM)PixMan Wrote: Dave is right, you need a LOT more speed to get the finish better.
How fast does your lathe spindle go? Even at 2400rpm with a 1" bar of stock you're just getting into the recommended cutting speed for grade WPP20 on annealed 4140, so let 'er rip! It's just a guess, but it looks like you're running about 400rpm. If you're afraid to try it, start by upping it one step up at a time without cutting, just to see how it runs. You need to get a lot more heat in the cut to get a good finish.
I suspected it might be related to RPMs. Good guess Ken. I think it was running at about 365 or 385. I'll do as you suggested and up it one step at a time to get used to it. I always turn things way too slow, I know. My lathe only goes up to 1500RPMs. The bar is .75" and I'm using the WPP10 insert. The portion I'm turning in the video needs to be turned down to .375".
Ed