Broken tap removal

Sat Aug 19, 2006 11:39 pm

I just finished removing a broken tap from the Cub's radiator casting.
Although at first I didn't know it, the broken off stud turned out to be a broken off tap. (No I didn't do it!) I tried to drill it first. The special drill bit that I bought wasn't special enough. I jigged it onto my metal lathe and used a HSS end mill. It wasn't "Special" either.
I finally ended up using a Dremel tool and a bit with an cylindrical abrasive end on it about 1/8" dia. x 3/16" long. I didn't think it would do the job - just break up or not cut at all or load up and quit cutting.
I used it just like an end mill. I kept blowing the hole clean with compressed air. It took a WHILE and 2 bits, but I cut through the tap and picked out the pieces (Of course the hole was it was off center by now and not circular).
I then drilled the hole true with a tap drill and tapped it for an oversize
threaded plug which was then cut flush with the surface.
Finally, I then center punched the plug where I wanted and drilled and tapped for 1/4 - 20 thread since he other holes were that size.
Just as easy as pie! Don't sell that dinky Dremel setup short.
Hope this helps someone. Rich

Sun Aug 20, 2006 9:20 am

Rich, I have never used it for that particualr applicatiion, but a variable speed Dremel has saved me uncounted hours and expense. I have a medium sized tackle box I carry to hold the large number of bits I have, including some very small diamond coated grinders in cylinder and tear drop shape, slighly smaller than a kitchen match head, which probalby would have been a great tool for that job.