Broken tap removal

[P. Waller]

Still wondering the price range to EDM this out. Anyone have an idea?

This depends entirely on the business that the shop is in and the machinery that they have, there is no way to even begin to guess what someone may charge you or if they will consider doing it at all.

 

[savarin]

You could build a very simple edm and burn it out your self,
https://www.hobby-machinist.com/threads/tumbler-reverse.10122/#post-97243
starts at post 19 and links to the plans are further down.
I also use it to make tabbed washers by turning up a brass plug, cutting in a key way then using that as the electrode.
https://www.hobby-machinist.com/threads/keyed-washer-spacer.40953/
My machine is a bit of a kludge but, it works and has saved me many times so far and no I still haven't beautified it.

 

[MarkM]

I ve had succes removing taps simply by using a drift and a hammer to break the swarf from the tap and use allen keys down the flutes and rock it back and forth.

 

[Downunder Bob]

A great method for removing broken studs from larger size holes, say 5/8 and above, in cast iron. set up an oxy acetylene cutting torch and with a very steady hand heat the stud until red then very carefully give a short blast with the cutting oxygen, it will blow the bits of stud away without damaging the cast iron, after allowing it to cool clean out and retap the hole, and it's good to go.

 

[rwm]

Where are you with this? Maybe it really is time to start on that next project...EDM as Savarin suggested!
R

 

[Airpirate]

I requested a quote from the MDM guy in CA. I got tired of screwing around so I recut and machined one of the beams where my broken tap is. Drilled the holes with a #35 drill and threaded the holed with an M35 cobalt spiral flute 6-32. It cut like butter, I still babied it and cleaned every turn and a half but total success! I'll still see what the quote comes in for the MDM may still do it for a spare beam.
Thanks all for your helpful suggestions.

 

[SamI]

Another suggestion would simply be to leave the tap in there! Depending on what the holes are for it is sometimes possible to relocate them, possibly by rotating them around by 45 degrees for instance. The remaining holes can be plugged with threaded rod held in with loctite to ensure that they are not inadvertently used.