[AT] EDM (Electrical Discharge Machining) Drilling on old tractor steel and iron.

[Gene Dotson]

    We knew it as a tap burner.

                                Gene




-----Original Message----- 
From: szabelski at wildblue.net
Sent: Saturday, November 02, 2019 10:18 AM
To: Antique Tractor Email Discussion Group
Subject: Re: [AT] EDM (Electrical Discharge Machining) Drilling on old 
tractor steel and iron.

When I worked in a tool and die shop we used a tool to extract broken taps. 
The tool consists of a set of fingers that look like small Allen wrenches 
and a handle that the fingers go into. You slide the fingers down into the 
tap flutes and then into the handle. Then you tighten a collar on the handle 
and it secures the fingers in place . Then it’s just a matter to turning he 
handle to remove the tap. Works great as long as the tap hasn’t shattered 
into pieces, then you have to sit there and pick out the pieces (usually 
just a few pieces near the top of the hole) one at a time until you can get 
the tool to work.

When this wouldn’t work, the tap would be burned out. This was usually only 
done when the tap had broken into a bunch of little pieces that were all 
jammed up in the hole.

Don’t remember what the tool is actually called, but you should be able to 
search the internet to find it.