Carbide drill bit stuck in mild steel part.

[Chris123Participant @chris123]

[Chris123Participant @chris123]

I have managed to snap a carbide drill bit in a mild steel part I am making.

It is a 2.5mm drill bit, and has snapped below the entrance of the hole.

Is heating the part to expand the hole worth trying do you think? Alternatively, any other ideas?

Thanks,

[Sub MandrelParticipant @submandrel]

Anytings worth a try. You might be able to get a carbide bit to shatter if you can hit it with a suitable small steel drift.

If all else fails, use a hollow bit to drill a hole around the broken stump, then thread that hole and fit a bush in it.

Neil

[David LittlewoodParticipant @davidlittlewood51847]

Chris,

Three possibilities spring to mind:

(1) Find someone with a spark eroder. Not sure how good they are with carbide, but in theory should work.

(2) If you can drill from the back, do that and punch it out.

(3) Use a core drill to cut around it, then fill the gap with a plug.

David

[roy entwistleParticipant @royentwistle24699]

Spark erosion at Pear Tree Engineering 1 Therlmere Road Golbourne Lancashire

Phone 01942 715528

If thats any help I've not used them myself but could be worth a ring

Roy

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Hi Chris ,

The normal home workshop methods don’t work very well on carbide .

The only simple method is to drill in from another direction and drift the broken drill out .

Ideally on the line of the original drilling but from other side of work .

If all else fails come in sideways at an angle .

MikeW

[KWILParticipant @kwil]

Why were you using carbide on mild steel?

[Chris123Participant @chris123]

Some good ideas, thanks.

Its probably easier just to re-make the part if expanding it with heat doesn't work, I just wondered if there were an tricks someone might know that I didn't!

I was using carbide as it was the only drill bit I had in the right size! I've bought some HSS now.

[JasonBModerator @jasonb]

Chris is it actually a carbide bit or one of the 8% Cobalt ones you were selling described as Carbide, if it is then you may be able to drill the HSCo with a solid carbide drill.

J

[Chris123Participant @chris123]

Hi, yes the 8% HSS ones. I've tried heat and it didn't work so I'll just make another one.

Thanks.

[Anonymous]

A carbide slot drill will remove a broken HSS drill with no problem – Andrew

[Author]

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