01-04-2015, 10:35 AM
(01-04-2015, 10:04 AM)PixMan Wrote: I think the most common mistake made in cutting metal is that of being "too easy" on tools in regards to overall material removal rates. The tools tend to fail primarily from "rubbing them to death" long before they would have been killed using deeper depths of cut and higher feed rates.
That said, 1018 steel seems to have just enough carbon in it to "work harden" a bit when tickling it with light cuts and slow feed rates.
Ed, were those end mills made of HSS or carbide? What diameter and rpm was used? I know the big variable here is feed per tooth (or inches per minute, etc) because your machine is without any power feed of known values. You just need to keep the tool working a little bit. The 1018 steel won't get particularly hard, but it can be very abrasive on tools if you don't keep them working a bit.
Ken,
The end mills are HSS, 1/2" diameter, 4 flute and I used about 960RPMs per Tom's chart. I don't think I could have gone any deeper on DOC without the mill complaining. I probably did feed to slow and maybe that's what caused the problem. I think I need to bump up the priority on the power feed. I have everything for it but just haven't taken the time to make the parts. I think I'll finish the knurl holders and then divert to the power feed project.
Ed