Thread: Bugga. Broke a tap

EDM machine

Hi Michael, when I'm put in a position like that, I get the Dremel/die grinder out with a carbide burr and try to cut one of the flutes off, usually works. With a small tap like that, it might be easier to try to grind it out using a ball burr. As a last resort, a small masonry drill could be used, the end result will possibly be an oversized hole, requiring a plug and re-drilling/tapping.
HTH Kryn

When you tried grabbing it or hitting it with a punch did it move at all.

If it did move it might still be able to be removed with the use of either a pair of long nose pliers or fine point circlip pliers,it should be a 3 flute tap so it want be that easy to get a good hold,if either of the pliers don't work you may be able to use some small rods down the flutes,grab these and try to turn.

I have had success with long nose pliers, put the "nose" between two of the flutes and back it out, needs to be a large enough tap to accommodate the pliers of course, I a not familiar with M3 so not sure if it is big enough.

Buy a cobalt drill bit and drill it out.

Originally Posted by alexm1

I have had success with long nose pliers, put the "nose" between two of the flutes and back it out, needs to be a large enough tap to accommodate the pliers of course, I a not familiar with M3 so not sure if it is big enough.

A carbide slot drill will drill it out

https://www.youtube.com/watch?v=YbeKxFBZrF8

Easy with the right tools

Good luck

How much you want to spend?

http://omegadrill.com/wst_page2.html
http://www.ebay.com/itm/T-O-Broken-T...-/321040191436

I've drilled HSS before, but it was a punch not a tap.

I've also seen but never used this sort of thing. (sure the pic is for an M16 tap but it was the only good picture I could find, you get the idea)

Stuart

One of these may work

http://users.tpg.com.au/agnet/microgrinder.html

Let's be realistic here guys, we are talking about an M3 tap buried in cast iron, the suggestions of drilling, milling or sticking something in the flutes just won't work unless the tap is loose, even getting it out with an EDM would be difficult without damage to the 2.5mm hole. I have removed broken taps and drills with EDM but never this small.

What is the possibility of drilling oversize , filling either with metal or braze and re-tapping ?

Hi Michael,
M3 is probably too small to remove with all the obvious tools. I would make hole saw from some silver steel 4mm id, 6mm od, harden drill out the tap & plug with cast iron. Quicker in the long run.
Ian.

The hole is a horizontal one in the side of my mill table, so we are talking a hefty piece of CI here (I'd estimate 100kg upwards - this is not a mini mill here guys). I don't even want to think of taking that off and welding or EDMing. Apart from the distortion, brazing or welding would also take a lot of heat, so that is not really practical.
The pliers or extractor may work for a larger tap but this is M3 we are talking about and jammed in. No loose fit here. I may be able to use a burr on a dremel if I can find one small enough. Perhaps a diamond engraving tip if I can think how to keep it cool so I dont kill the diamonds (squirter bottle maybe). A carbide or cobalt drill may do the trick but apart from the size, they need rigidity and the only thing I'd have to drill with is a hand held drill - not the best of set ups.
A tap disintegrator may be the go but I've been looking for a cheap one of them off and on for many years and never found one. I have plans to make one but that's a long way down the list. The cover plate is for a job that I first thought about several years ago and got the bits for around a year ago. At that rate the home made EDM is due for completion in around 2017...

Michael

On edit - Ian's hole saw suggestion may be worth trying too.

Before drilling out too much I'd hit it with some freeze spray and try to shatter it. The nozzle should be small enough to get in to an M3. I don't know how deep it is, but if it's too deep for a prick punch I'd probably sharpen up a pin punch to a point to help shatter it, alternatively turn up some silver steel to the appropriate OD, then grind a point on it, harden and temper it.

Put the nozzle in to the hole and flood the tap with freeze spray (available from electronics repair shop if you don't have some). Straight away take your punch and smack the tap well. It will either shatter or the combo of that and the freeze spray will loosen it up and you may be able to back it out.

After my haul of "hey these are cheap!" Indian taps you and Bob so liked to rib me about, I got pretty good at tap removal until I threw the last of them in the bin in disgust