Re: [CAD_CAM_EDM_DRO] Simple EDM schematics...

Joe Vicars wrote:

>
> Hey Lee,
> If you just need to get one tap out it wouldn't be practical to try the HSM plans.
> I would say a "traditional" broken tap removal would get you there before building your own, unless you can get a loaner.

> 1. tap removal tool
> 2. hole saw, plug and re drill. Some call this a trepanning drill.
> 3. knock it out with a punch, re-drill, plug hole
> 4. weld something on the end if there's any sticking out
> 5. borrow somebody elses sinker EDM

Joe, for a tap broken off in aluminum (or brass) you need to add
one more technique: make a saturated solution of aluminum
sulfate (or potassium aluminum sulfate = alum) at about 120 deg
F. Put the workpiece in the solution with the broken tap
submerged. Tap will disolve out. Goes quicker when hot but
works when cold.

Don't ask me how I know this work fine :-).

JerryK