Does anybody have a technique or pointers for profile cutting purpleheart?
I am set up with a router table, with a new “up-cut” 1/2″ shank spiral cut profile bit by Whiteside. The router is set at 10,000 rpm. My real difficulty is blow-out and binding at the end grain.
Any help would be greatly appreciated.
Replies
Purpleheart is considered relatively difficult to machine.
If the bit is a small diameter, increase the speed to the max and pre-trim the purple heart close to the finished size so you are only removing 1/8" or less.
With an up cut bit some blow out is very likely on the top, so place the good face down. If both faces are going to be visible you'll need a different bit. Dampening the wood just before you take the cut may help.
I'm not familiar with the term "binding" when routing.
John White, Shop Manager, Fine Woodworking Magazine
Ditto JohnWW on the trimming. A Spiral compression grind(both up and down spirals on the same bit, meeting in the center) will eliminate the tear out on both surfaces.
Work Safe, Count to 10 when your done for the day !!
Bruce S.
I have not done profile routing with purple heart but have found in profile routing in general that it worked better for me to use a guide bushing in the base plate rather than the bearing integral with the straight cutting bit. Reason being (I think) by pushing against the bushing you are not deflecting the bit as when you are pushing the profile on the bearing on the straight bit. Second if you start one bushing bigger any tear out or chips can get cleaned up on a second pass with a smaller bushing similar to the pevious comment about trimming as close to the line before routing.
Charlie
As mentioned, purpleheart is a bear to work with. After tearout frustration on one project with a router I opted to bandsaw as close as possible and finish with the spindle sander. More time consuming but I got a very nice result.
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