If the broken drill bit is into fiberglass. Try using a small wood plug bit and drill it as if you were making a plug. Drill only deep enough to reach the drill bit. Dig out the material which is now like a screw plug. Be Careful side-loading the drill bit on smaller bits or you could snap it off removing the plug material. .25 drill is pretty strong. I wouldn't to much about side load with a .25 drill, but in general. Then you can get a hold of the drill bit with short needle nose pliers. Don't use vise-grip pliers on it. They will tend to crush the bit and snap it. Don't hammer on it you will break it off deeper. A shot of tap magic on the drill bit will make the bit break free easy-er. Remove it counter clockwise and good luck. Never use a carbide drill bit when there is the chance of an interrupted cut. Any type of carbide bit will not stand up to the shock of an interrupted cut. Use the smallest plug bit you can. Then you can easily plug the hole. It works for me.
BILL
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Thread: Removing Broken Drill Bit
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11-07-2008 07:31 PM #11
Re: Removing Broken Drill Bit
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Re: Removing Broken Drill Bit
My vote is for:
1) the drill bit extractor
2) a hole saw or plug cutterl, to cut a core around the bit, then go after the bit. You can re-build the hole with fiberglass and resin to good effect. Entire transoms are grafted on to motor yachts to make CP MY's, so re-build a small hole is possible. But ensure you include fiberglas mat to provide strength.
3) The issue with tack welding a bolt or electrode to the broken drill bit is a good ground, so that, although the embedded plate may not (or should not be) be grounded, the bolt you're chasing does not weld itself to the embedded plate. Make sure you get help with someone experienced with welding gear. Oh, get some goggles...you don't want the sand-in-the-eyes effect for a week if you catch the arc close up with bare eyes.
Leaving it? I am too picky- I would know its there and it would drive me crazy over time.Last edited by spartonboat1; 11-08-2008 at 10:56 AM.
50 Years on the Great Lakes...
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11-08-2008 05:43 AM #13
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Re: Removing Broken Drill Bit
Actually I would think somebody could make a kit and sell it it, yes I have done the tubing bit too, its never the same and even the heat alone is sometimes enough to change the grip in the material. Also as an off the wall thought was if somebody had some really cold stuff like liquid nitrogen and pour it on the bit and wack it with either a pneumatic bit or something hard enough to fracture it.
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TIG welding...your friend
As a master fabriactor, I've removed broken/stuck/shattered/ blind hole pins/taps/drills/etc a zillion times.
If it's a tap, tig weld onto the back of the tap, making sure to weld all the pieces together (they usually shatter lengthwise) and buld up a "T" handle drop by drop. The heating/cooling cycle breaks up the molecular bond at the point where the tap is sticking and anneals the tap so it doesn't shatter more when you twist on it. After it cools, apply Moly Dee (accept no substitutes!) and the offending part can usually be turned out with fingers. If you don't get all of the part the first time the Moly Dee can easily be washed out with a squirt of acetone so you can try again. Most oils can't.
This only works on a gounded part of course.
For broken drills/pins and so on, make a mini slide hammer with a pointed tip. ground the slide hammer (grounded/conductive parent part not required) and weld it onto the end of the pin. Let cool and tap out the stuck part. I've used this method on 1-1/2" drills in huge die plates and 1/64" pins in the brass body of $300,000 microscopes, and everything in between. The guy who broke the thing (the guy who's ass you're saving) thinks you're a genuis.
If you don't happen to know a weldor who's NASA qualified to weld space flight hardware (like me) find the guy that builds towers in your local yard, he can probably help you out."The older I get, the faster I was......."
1979 60C "Ohana" hull# 331
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Re: TIG welding...your friend
I love this site...super-duty smart guys and their knowledge. Also, I am jealous...so many cool things in life that we can't know and do. Of course I am at the 3rd stage of learning in life- I know there is someone smarter that me on all topics and I want to know who they are and where they are so I can get them for my project!
50 Years on the Great Lakes...
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11-08-2008 11:03 AM #16
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Re: Removing Broken Drill Bit
You guys are a riot why don't you recomend a laser denaturizing atomic ray gun that would be about as usfeull. The poster's a guy working on his boat that had a bit break off do you really think he's going to hire someone with welding equiptment to come down for this?
Trojan's got the best idea something that will probably work and can be done without the help of NASA
Brian
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11-08-2008 06:08 PM #17
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Re: Removing Broken Drill Bit
Well, I guess that puts the kibosh on my suggestion to call up the local general Aviation airport and see if there is a tech available with a Spark Erosion machine or EDM (electric discharge machine).
Instead, why not try to tap two thin nails down into the flutes, grasp them with vise-grips and try to turn out the drill. You don't need much grip, just enough to break the drill free, anyway it's worth a try....
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Re: Removing Broken Drill Bit
What a great idea! Why didn't I think of something like that?
Last edited by Avenger; 11-08-2008 at 09:48 PM.
--- The poster formerly known as Scrod ---
I want to live in Theory, everything works there.
1970 36C375
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