Broken drill bit removal???

I need to remove the broken section of a fine drill bit from a pilot hole in a part I'm working on. I've tried punching it through (drilled in from the other side), I've tried some heat and punching it through. It really seems to want to stay put.

The easiest thing to do if possible would be to drill it out with a bigger drill bit. Can tool steel be annealed or something to make this possible?

Any other old timey tips?

Pete

 

They can be really tough sometimes depending on how much is left sticking out. I have taken a very tiny chisel and tapped on the sides of one in the reverse direction you drilled and tried to back it out that way. If you can get it turning just a tad they sometimes will loosen up. Penetrating oil can help too. It just takes patience and time.

Don

 

There was a tiny bit sticking out but I fixed that up. Now I have nothing I can get a grip on. It's just in there blocking up a perfectly good hole.

 

Drilling from the other side should do the trick. You could also try a masonary drill(carbide tip).

 

I've heard of welding the hole up and starting over but not sure how well that works. If you have a very small punch you can sometimes keep hitting what is left of the bit sideways in all directions to try to make the hole slightly bigger, enough to then tap the bit out from the other side.

Don

 

Yep. I'm getting the picture. The answer is there is no easy way. Much like I have found already, it's just a frustrating, time consuming pain in the ***.

But thanks for the advice guys.

Pete

BTW the bit is smaller than 1/8". I can't remember exactly what size.

 

We have had a few broken drills and taps removed with a spark eroder.
Ring around a few engineering shops to see who has one.
The cost will be ****** all and they are ideal for removing the bits from blind holes.
The other way at home is as 57 heap said,use a small masonary bit at a real slow speed. Good Luck.

 

I seen in the automotive trade mags tools made just to remove broken drill bits and broken tapes. Check in line.

 

Truth be told I could probably remake the part in less time than it would take to chase up a spark eroder...but thanks. A small masonary bit might be worth a try. My final hole size is 1/4" so I could probably use a 1/4" masonary bit.

I might also check this out. Can't hurt to look.

 

If you have drilled from the other side, I'd take a good quality hardened punch with a perfectly flat end, and bash it through. Bits are very brittle and it should go.

 

i've been able to grind them with a dremel tool also you can give it a quick hit with a plasma cutter.These metheds have worked for me in the past,the only way to drill it would be with carbide.

 

That was my first thought. I bashed for a while but because of the small size, eventually the punch bent. It was a my smallest pin punch.

 

Do you have a picture?

 

No. It's nearly midnight here so I'm not going out happy snapping now. Do you think it would help? I'm not sure it would tell you much.

 

Work piece size? Shape? Material? Application?

 

How about cutting around it with a fly cutter like the ones used to cut spot welds. I have a whole set of them that I haven't used in 20 years, got them off the Mac truck IIRC.

 

That's what Ive done to remove broken drill bit or broken easy out. The Dremel bits are too fragile but buy a couple four packs of chain saw sharpening bits from home improvement store.

Since its a pilot hole you don't have to worry about enlarging it. Each 3/16" or 5/64' chain saw bit will get about 1/8" deep before breaking or wearing out, It goes slow but it's worked for me

 

A1/4" hole saw with the pilot drill removed.I don't know if there is such a thing but you get the idea.

 

Don't know about where you live, but around here having someone with an EDM remove it would not be dirt cheap. If the part will allow, drill a larger hole beside the broken drill, use a punch to drive the drill into the hole, weld up and redrill. I've done this many times, but never with a tiny number drill. Good luck.
High speed steel drill bits aren't hard, they're tough, ductile. Carbide is hard and brittle. I doubt a small carbide drill bit would survive a raggedy hole.

 

I had a shop teacher in high school who I watched remove a broken off tap that had been run into a blind hole until it broke(i'm not sayin who did that) He used a cutting torch to remove it, he didn't heat until multen however just heated for a few seconds and then blasted it with oxegen and it came out with a loud pop and a spray of sparks. he said it worked because of the high carbon content of the tap. maby someone else has done this and can elaborate.
I dried this a few years back but backed out of the oxegen too soon and only got part out, seems it's a one shot deal.

 

depending on the size I have had good luck by driving a cotter pin as far as possible and grabbing it with a small cresant wrench, works good somtimes with 4 flute taps also

 

You could try welding a nut to it. It would be a delicate procedure though Doctor!!!

 

Was going to be my suggestion...if it is a pilot hole, no real damage would be done, and if you can get at it and carefully weld a nut to it you should be good to go.
I recently broke a tap while re threading the thermostat housing bolts on my SBC, and this worked very well.
Cheers.....

 

Try acid in the hole if you can wait awhile, it will eat on the part and loosen the drill.

 

Breaking a drill bit off in the pilot hole has been a real nuisance lately. I managed to remove the broken drill bit that seems to be wedged flush in the pilot hole with various dental tools. The tips of the dental tools are very hard and if you can get the dental tool tip in the spiral of the broken drill bit it will pry out.

 

I've had some luck turning a can of computer duster upside-down and spraying the drill bit (works on bolts too) to shock freeze the item that is stuck. It rapidly freezes and of course shrinks whatever it is thats stuck and can be just enough to get it out sometimes. Try to only spray the drill bit if at all possible, then whack it with a drift or punch.

 

I have removed many taps and drills with a TIG welder. I just keep building up the top of the drill/tap untill I can get a good grip with a pair of Vice grips and turn it out. The smallest I have removed so far is a 2-56 tap in aluminum.

 

What's the application? Can ya' get it on a mill and use a carbide end mill?

 

how thick is the material you are drilling and what size hole did you want to drill in the end, this will help in giving you advice.

 

Rottenleonard,

I used this method to get a broken tap out of a blind hole in a head.

The blast of oxygen would create a blob of slag on the end of the tap. Then I used a punch to break up the slag, cleaned out the hole with air and took another shot until the tap was out. Each try got around 1/16" of the tap so it was kinda slow.

I managed to get a 3/8" tap out of a cast iron head without damaging the threads. It did raise a small lip around the hole that I used a flat file to remove.

I don't think that this method will work with the small drill bit that we are talking about here.