Broken tap removal.

Hi All,
I have just snapped off a 5/16 BSF tap in a thread hole just below the surface -Help! I have tried to drill it but my drills wont touch it. Any ideas on how I can get the broken bit out? Thanks.
Kev.

This should be interesting!!!!

You will swear a lot getting this out I reckon. What is it in? BSF is an uncommon thread. You "might" and all these are "might" be able to tap it back with a small punch, you could try welding a nut to it, maybe getting small pin nosed pliers down to turn it...

Thanks for getting back to me so soon.
It is in a cast iron engine block from a Stuart Turner R2.I have tried using a small punch but there is not enough room to use it effectively.I hadnt thought about pliers - I used mole grips on the small piece that was proud of the surface but that just broke away!As you say this will be interesting!!
Kev.

Hi welding a nut won't work in this case the heat will make it brittle.
If you don't get any where and really are struggling, search for a local engineering shop that does spark errosion.

Hi All - an update - I gave the broken tap a good squirt of freeing fluid then tried, as Villiers suggested,  some thin long nosed pliers after a bit of wriggling it moved a little, just enough to be able to get a thin punch to bear.After tapping it for ages it slowly unwound and I was able to remove the bits.Phew- was I ever relieved!! I wasn't first in the queue when luck was handed out but every so often the Gods take pity on me and give me some - this was one of those rare occasions! Thanks for your input guys.Kev.

So glad you sorted it, worth it just so you feel smug!

glad its out - I have done this a few times and its never easy to remove them I have in the past had to melt one out with my tig welder.

I would had to resort to looking for a spark erosion machine so very well done. Take a well earned pat on the back, or maybee just a small drink....

That was a good idea with the punch. I wouldn't have thought of that. I have often wondered why left hand drills are not so easy to get hold of. Reasoning that even if they won't actually drill the tap or stud out maybe the 'unscrew' vibration will help.