Broken drill bit stuck

[WolfieParticipant @wolfie]

I actually got to my workbench today for the first time in ages. Picked up where I left off which was with 2 pieces of aluminium clamped together ready to be drilled through.

 

The bit promptly broke around half way through the second piece and when I tried again in another hole the (second) drill broke again at around the same point.

 

2 things arise from this, is there a reason they both broke in teh second piece, was I doing summat wrong??

 

And how the hell do I get the broken piece of drill out of my piece of ally. Its a hole thats open at both ends but I've hammered and hammered and the bloody thing won't shift

Edited By Wolfie on 05/10/2014 08:35:07

[WolfieParticipant @wolfie]

[Ian PParticipant @ianp]

An indication of diameter and size of parts involved would help. I have had similar events, sometimes when drifting broken bits of metal out they 'dig in', maybe trying to go slightly sideways and the broken bit effectively becomes embedded.

If the proportions and the metals are amenable, brute force might punch a whole slug of the parent metal out leaving you to a change of design. (bushes, Helicoil etc)

Ian P

[Neil WyattModerator @neilwyatt]

Welcome back stranger

Soak it in alum solution and the steel will corrode away over a day or three.

If you ever want to keep the steel not the aluminium use caustic sode instead.

Neil

[WolfieParticipant @wolfie]

Its a slab of ally about half an inch thick and the hole is 2.3mm. It was the upper of the two pieces so the hole is right through

[jason udallParticipant @jasonudall57142]

To recap.

Two slabs of ali..

Same alloy

1.5" thick each

Drill breaks in upper slab before breaking through. .about half way ..ie 0.75" deep

..and twice at approximately the same depth…

So my first thought was lower part moving and "scissor ing" thus gripping the drill ..

It appears not.

If as I have summarised its breaking in the first layer..my guess would be maybe swarf jam

Or an inclusion in material. ..

[JasonBModerator @jasonb]

I've had similar happen when swarf pushed the two plates apart and got stuck in the gap then jamed the drill.

Were you drilling dry or lubricated and how often were you lifting the drill to clear teh swarf?

[Eric CoxParticipant @ericcox50497]

Same happened to me last week, small diameter drill. It was caused by swarf clogging the flutes. The swarf virtually "welds" itself to the flutes and that's why you're having trouble removing the broken drill. Don't drill too far down before you remove the drill and check the flutes, take your time and check often.

[Bob Brown 1Participant @bobbrown1]

Paraffin or similar (wd40) will reduce the swarf sticking to the drill not forgetting to peck drill adding lub as you drill

[Tony Pratt 1Participant @tonypratt1]

Lack of lubrication & not clearing the swarf is the likely cause.

Tony

[Ady1Participant @ady1]

As mentioned, ally melts onto the cutting edge and welds itself there. I tend to use backgear for turning or drilling ally so there's not enough heat generated to cause a problem

[Author]

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