On Apr 8, 10:18 am, "Nick Leone" wrote:
I seem to recall from the book "machine shop trade secrets" a procedure for
broken tap removal that looked promising. His suggestion was to use a round
peice of carbide (in your case, probably 1/16") and grind a spade shape in
the end of it. From there, mount it in a mill and VERY slowly feed it into
the tap. It will (supposedly) cut right through.

That said, I've never tried this procedure, and 1/16" tool won't be very
rigid.

Do you have access to a wire-fed EDM machine?

-Nick

"Michael Gray" wrote in message

news
Well, Google so far has NOT been my friend.
With a HSS 2-56 tap broken off in a lump of bronze I did my search -
found reference to "jewellers' screw remover, a white paste". Looked all
over the place in jewellers' webpages and couldn't find a thing.
There was recent reference here to the use of alum (septic pencil), but I
believe that was for use for a tap snapped off in aluminum.
I could move the hole over and retap, but it would throw off the symmetry
of the piece - however if the worst comes to the worst.
Help!
Mike in BC

I used James' Harvey's technique with a 4-flute solid carbide ball
endmill, pecking 0.005-0.010 at a time against the quill stop. It
made short work of my 1/4"-20 tap, but I wouldn't try it with a tool
any smaller. The forces involved in the process far exceed those
encountered in ordinary drilling...