Drill retrieval

[Mr Grumpy]

I have broken a 0.6mm drill bit in a white metal casting. The hole is adjacent to some detail, so a little cautious on how to retrieve it. The hole had previously been drilled right through wit a 0.5 MM. Drill, so I have tried tapping brass rod from both ends with a small hammer, but it won't shift. The drill bit is not protruding from either end, so can't grab to twist.
If anyone can pass on any tips I would be grateful!

 

[Tim V]

Seized in. I doubt you will be able to get it out. Do you need the hole?

 

[Dikitriki]

Given the thickness of the DJH castings, I carefully mill out the white metal from the back of the casting around the original hole using a Dremel or similar, until I can either grip the broken end with pliers and pull it through or knock it back. Of course, if you have detail on the back of the casting. this won't work.

Richard

 

[Dog Star]

How about drilling a small hole adjacent to the broken drill and then cut towards the drill with a piercing saw... work the saw blade around the sides of the broken drill piece so as to relieve the grab between the casting and the drill. Continue working the blade around the drill until either the saw drags the drill out or you feel that the drill is loose enough that you can knock through. Tidy the hole and then fill with low-melt solder, say 100 degrees, smooth the surface and drill the hole again... with cutting lubricant such as 3-in-1 in white spirit.

 

[Mr Grumpy]

Thanks for the ideas chaps!
I will try to mill out the casting from the rear and try to make a grab for the broken drill bit.
The other piece was easy to retrieve... It was in my thumb!!

 

[Mr Grumpy]

Following a little milling and using a drift, the drill bit has been evicted!
I just need to melt in a little solder, dress and re-drill.
Thanks again for your suggestions!

 

[AndyB]

Glad to hear of the successful eviction.
I described a technique for removal from non-ferrous materials in this thread - post #244.

Andy