Posts: 1,459
Threads: 159
Joined: Feb 2012
Location: Northern England
Hi
I would think a thread that course would cut wood no problem with standard metal flutes
Metal spinning now that sounds interesting
Looking forward to some pictures
John
Posts: 3,799
Threads: 184
Joined: Jun 2012
Location: Farmington Hills, Michigan
I would make the flutes with a little positive rake so the teeth cut the wood with a shearing action rather than a scraping action. That should give you a much better finish in wood.
Tom
November X-ray
Unregistered
(06-24-2012, 04:19 PM)TomG Wrote: I would make the flutes with a little positive rake so the teeth cut the wood with a shearing action rather than a scraping action. That should give you a much better finish in wood.
Tom
Any suggestions on how best to cut the flutes with a positive rake? I was thinking about using an endmill to make the initial cuts and then swapping to a small ball endmill since that's all I got. Would three flutes be better than four for wood or will that matter much?
Thanks for the replies!
Posts: 3,799
Threads: 184
Joined: Jun 2012
Location: Farmington Hills, Michigan
(06-24-2012, 04:19 PM)TomG Wrote: Any suggestions on how best to cut the flutes with a positive rake? I was thinking about using an endmill to make the initial cuts and then swapping to a small ball endmill since that's all I got. Would three flutes be better than four for wood or will that matter much?
Thanks for the replies!
Depending on how small your ball end mill is, you might need more than four flutes for a 1" tap. I would make one flute complete and then see how many would fit around the circumference of the tap. To get positive rake, all you need to do is shift the side of your end mill past center a bit when you cut the flutes.
Here's pic of a tap I made for my Steven's project. It has four flutes, but then it's only a #12. It also has neutral rake.
Tom
Posts: 3,003
Threads: 51
Joined: Apr 2012
Location: Ontario
A standard metal tap should work. According to Lee Valley Tools drill to the root dia of the thread for 100% thread rather than the tap drill size. In your case drill .8466 or 27/32 rather than the 7/8 tap drill.
Free advice is worth exactly what you payed for it.
Greg