[1abrat]

Guys I screwed up.

I was trying to drill out a hole in 17-4 using a HSS drill bit. The bit was 0.070. It would have only been removing 0.004" on each side. I ended up breaking the bit in the hole. I have to eventually tap this whole all the way through. It's a through hole.

How can I remove this drill bit without messing up the part? It was an expensive DMLS printed part. What about alum or any of those other fancy chemical techniques? I guess I could drill it out with a carbide drill bit. I should probably invest in some carbide drill bits anyway.

Any suggestions?

[InMesh]

I have used a cheep rotary diamond bit to grind away at a 3mm tap before with great success after I calmed down I just attacked it from a few angles eventually it became loose .

[109jb]

You said it is a through hole. With drills I have usually been able to tap (as in hammer lightly) them out from the back side with a punch whe it was a through hole

[Bradrock]

For me, Optivisors are a great help in these situations. Much easier when I can zoom right in there and see what's going on.
Like said above, Dremel or Foredom & diamond burr. Like doing surgery ,when you want to save the part.
Maybe even try a hot air gun to expand the part a bit. A little lube, tap tap tap & it might just rotate out.