How would you profile , with a 1/4" end mill, a piece of Purple Heart wood?

[banderson]

I'm trying to profile a piece of Purple Heart wood with an 1/4" end mill!! and I want to know where to put the router speed at, the feed rate.... Stuff like that!! Anyone have an idea?

[dlcw]

I don't normally do exotics on my CNC. I do them on my router table.

I set the speed to whatever is appropriate for the size router bit I'm using and away I go. I always do a last pass that is a very shallow cut and I go quick so as to reduce or eliminate burning (purple heart burns really well) :eek:

[banderson]

Soooo what would be an appropriate speed for a 1/4" end mill?

[bryan]

Bret, I've cut some purple heart with a prt shopbot,
using a 1/4 inch spiral end mill, I only have router on my cnc, haven't pulled the credit card out for the spindle yet.
cutting at 16000 rpm running at 110 to 115"/min x/y movement, 45"/min for z
only cut .15 per pass to make sure not to burn this very hard wood.

attached an image of the inlay that I cut out of purple heart.

[knight_toolworks]

1/4" pass depth 8k rpms 3ips best to use a downcut bit.I have cut a lot of it. be sure to use a climb cut and a regular cleanup pass. Some pupleheart is very hard some not so. compared to ipe or lignum vitae or desert ironwood it is not as hard. but without a downcut you may get a lot of tearout. or a chipbreaker bit would work. I have used a upcut rougher with success too.
http://i154.photobucket.com/albums/s266/knighttoolworks/plane%20kits/coffinkit.jpg (http://s154.photobucket.com/user/knighttoolworks/media/plane%20kits/coffinkit.jpg.html)

[Bob Eustace]

Steve - we have to do a mariners compass with customer supplied purple heart and we are nervous as the stuff is so dear in Oz we keep it in the safe. On a Buddy would 2.5 with 1/8th pass be OK do you think at say 8K?

[Simops]

Bob, where do you get your Purple Heart from......AFT?

Cheers

[Bob Eustace]

Yes AFT but get in quick their site is up for sale sadly.

[Simops]

Bugger! It's so hard to get any decent timber in this banana State! :eek:

[knight_toolworks]

no problem less per pass. for the most part the only difference between cutting hardwoods is tearout (donwcut pretty much eliminates that) its more a matter of bit and machine flex. the part show before I discovered cleanup passes I would cut with a 3/8" 1ips 1/2" deep. I would get tapered cuts. finally with a cleanup pass it took care of it. faster cutting helped with noise too.

[banderson]

Thanx Bryan and Steve for your help!! I'm ready to rock some Purple Heart!!