Extracting broken drill bits - my method.

[Ed of all trades]

I was a mechanic for a few years and have easyouts and left handed drill bits. The drill bits work best for me. Thanks for the tip. Ed

 

[Industrial Toys]

I don't know about HF but we have Princess Auto. I have learned not to buy anything that involves metal cutting from them. Only drill bits that I ever used that became smaller rather than the hole becoming larger.

 

[dickfoster]

Just to clarify. I was smashing the broken drill bit, not the bolt. The broken drill bit was only about 3mm this time, but I've used the method on larger broken bits. I think the bigger the bit the easier it would be as you can use a gutsier punch and have more room to move.

The bolts were well and truly rusted into a cast iron block of an old Wisconsin V4 that had been sitting in salty seaside air for years. I sprayed WD40 for a week, and tried a rattle gun, but in the end the heads of the bolts had to be snapped off to get the cylinder heads off the engine. But even then there was still plenty of exposed bolt left to get a grip with a pipe wrench. But no-way were those bolts going to budge. In the end i just had to snap them off at the base and start drilling. 7 of them!

You need to apply some heat.

 

[Farmer2750]

Drill a hole and hammer a torx head socket in the hole. Works 90% of the time for me

 

[4570Man]

Drill a hole and hammer a torx head socket in the hole. Works 90% of the time for me

If you have a hole drilled you can use an easy out. The bigger challenge occurs when you break a tap or drill bit in the hole.

 

[PJ The Kid]

Used this method alot, for bits and for easy outs, I dont like easy outs because as they bight in, they can swell the shank of the bolt out and make it harder to extract. Usually try welding a washer and nut on, the heat helps alot, then I rattle them off with the impact.

 

[Sodo]

Shattering thi bit---- that's really good stuff, thanks for posting!!!

My dad told me once of burning a hardened bolt out of cast iron with an Oxy/Acet torch, the threads were untouched. It was a blind hole - not thru hole. The bolt shot its own slag out the hole when it ignited. Can't do this method on a stainless bolt. Or Aluminum head....

I hear ya about the pilot hole depth (& risk). Basically you should think long & hard when considering a deep pilot hole smaller than 1/8". But a hole thru allows penetrating oil to the other side, a HUGE benefit to the extractor.

Welding a nut on --- its pretty difficult to get a weld thats stronger than the bolt that broke, but the heat helps to loosen the stuck thread. A pilot hole thru to inject PBBlaster to other side is good here too.

 

[alchemysa]

Used this method alot, for bits and for easy outs, I dont like easy outs because as they bight in, they can swell the shank of the bolt out and make it harder to extract. Usually try welding a washer and nut on, the heat helps alot, then I rattle them off with the impact.

I've never had much luck with 'easy outs' either. A bolt that is so rusted in that the head snaps off while you are trying to remove it is not coming out that easy.

 

[JRobyn]

I have a couple sets of the HF left-hand bits. They are ok, but use them VERY cautiously! They are quite fragile compared to a good quality HSS bit.

 

[PJ The Kid]

The closest I have had luck with is a set the dealership bought, basically works like hammering in a torx bit but a little more precise. Removing Frozen or Broken Fasteners | Metal Arts Press, Not the exact same thing but the same basic principal. I used it hundreds of times on broken exhaust manifold studs on fords when I worked at the dealer. Also, it was a little softer metal so as not to snap off if you made sure not to put any lateral pressure on it. If it didn't extract it was time to drill it out completely. ALSO, the one I used was in figure 6:37 on the link I posted