Feed & Speed

[jwa1156]

Attempting to carve stars into a piece of Purple Heart
using 60 deg 1/2 V-Bit
RPM 14000

What would be a good feed and speed
thank you

[Kyle Stapleton]

scott will tell you

[scottp55]

Overly optimistic Kyle

Jerry,
Haven't cut much Purpleheart in last 2 years, and you didn't say if it's a 2 or 3 Flute bit.
What is size and depth of the stars?
It cuts very similar to Bloodwood which I do more of.
I've only ever cut it with .125 and .25" shank 2 flutes and engraving bits, but here's my database for the Celtic Purpleheart button.

I think somebody who does bigger and more aggressive work will help more, but I'd probably test a couple stars on a piece of scrap at .7(IPS X,Y), .4(IPS Z plunge),15-16K RPM to start if it's a 2 flute, and keep the pass depth(if the stars are small) at .05" for starters.

Ballpark guess though only if they're small stars....if tearout, lower plunge and increase RPM slightly.
Hope this helps,
scott

[jwa1156]

Scott
Thanks for the info and guidance, The stars are small to get the scale correct for my max 24" desktop
only 0.6945 tip to tip and shallow my Aspire 8.5 has the minimum depth of 0.196 to not have then truncated
The female star's were cut successfully using several shallow cut to get to the max depth
The male stars are getting broken up.
Tried cutting stars, then cutting excess wood out
Then the reverse did a pocket which left the stars ok in the form of star shaped pillars, no point flat top
then tried to V Carve the pillars to form the actual star pattern
In the end the stars were all broken and in pieces, have used 90 and 60 degree bits.?

[scottp55]

Jerry,
Didn't realize you were trying to inlay the stars...if I were trying to inlay a field of stars I would VInlay it;
http://www.vectric.com/support/train...us/vinlay.html

It's capable of extremely fine detail and would keep the stars attached to the waste backing for clamping.
In my pics, all this wood work was done with an Onsrud .25shank 60degree engraving bit with a .01"flat.
I've read others are now using a 30 degree to make the fine details deeper for the inevitable sanding, and I'll try it on my next VInlay project.

I'm hoping that's what you meant(Inlayed stars).

LOTS of the threads on the Vectric forum about "VInlay" and "VCarved Inlay" if you do a search.
Hope this helps...maybe show a pic of exactly what the project looks like?
scott