Cutting mother of pearl

(Byrne Pedit) #1

Has anyone here cut pearl on the Nomad? (Think 1.5 mm thick blanks.) My last big concern before springing for a Nomad is the maximum spindle speed of 10,000. The PreciseBits website, where folks seem to have done a lot of experimentation, recommends speeds of 24,000 RPM. Will slower feeds compensate for reduced spindle speeds?

(mikep) #2

Or an endmill with more flutes.

(Daniel Loughmiller) #3

Yep it’s more about chipload, how much of a chip you’re taking in a single bite. If you can’t spin fast enough then move slower, both result in smaller bites. As mikep said more flutes means the cutters hit the material more times per revolution, doing the same.

(Byrne Pedit) #4

Thanks, well put as a guiding principle. The PreciseBits site offers three fluted bits for pearl. PreciseBits appears to garner information from several sources who do this with some meaningful experimentation. I’m trying to inagine a quality 4 flute end mill with a 0.25 mm diameter and a reasonable cutting length. If you have a source, please pass it on.
One issue cutting pearl, according to PreciseBits, is clearing the cut. It seems a bit with finer flutes, i.e. more of them, would have more of a problem in this regard.
Either way, it appears slowing the RPM would be the likely remedy for me.

(William Adams) #5

We have a bit of discussion on the underlying concepts at: Tutorial on feeds and speeds

and there were a couple of blog post by Bob Warfield and the community has some general notes at: