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Posted by Michael Gray on April 8, 2008, 12:57 pm
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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
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Posted by Nick Leone on April 8, 2008, 1:18 pm
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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
> 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
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Posted by woodworker88 on April 8, 2008, 1:46 pm
Please log in for more thread options > 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
>
>
>
> > 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...
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Posted by The Davenport's on April 8, 2008, 9:36 pm
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>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
<<snippage about a #2-56 broken tap in bronze>>
A wire feed EDM isn't gonna do a lot here...the chances of being able to get
a wire through, on location, aren't good. AND that's assuming that OP even
has a through hole.
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Posted by Nick Leone on April 8, 2008, 2:01 pm
Please log in for more thread options Looking around, there are several hacked-together EDM based tap removal
techniques on the web. Here are two that I found interesting:
http://www.pico-systems.com/edm.html
http://www.modelenginenews.org/meng/edm/p1.html
Do you think this is applicable in your situation? Ultimatly, it may be
less hastle to move over and re-drill.
-Nick
> 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
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> 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