

| Subject: | Re: Exhaust port bolt size needed ? Try This FIRST |
| From: | George Goff |
| Date: | Sun, 1 May 2005 11:35:40 EDT |
In a message dated 4/30/05 9:53:32 PM, kd5ceu@YAHOO.COM writes: << While drilling out one bolt, I broke a drill bit. Is there a type of drill bit that will drill thru the broken bit? If not, what is the easiest way to get it out? >> There is no easy way to get it out unless someone has come up with a handheld EDM (electrical discharge machining) unit about which I don't know. Try this BEFORE you go animal on it. Get a pair of miniature needle nose or round nose pliers, the smaller the better. If you do not have anything this small, regrind the tip of a standard pair without ruining the temper. Scratch around the broken drill with a scribe to see it there are any loose fragments, remove them with a magnet and blow out the hole with some air. Soak the mess with some penetrant then carefully insert the pliers into the flutes of the drill remnant so that you grasp the web of the drill. Now, WITH A DELICATE TOUCH, try rotating the drill remnant VERY SLIGHTLY back and forth. If you sense any movement, wiggle a LITTLE more. I'm telling you, this requires a DELICATE touch, so don't go berserk on the thing! Once there is some movement in the drill remnant, you should be able to back it out. Again, use a light hand, stopping if you sense any undue resistance and returning to the back and forth action. If that fails, try disintegrating the remnant with whatever (scribes, awls, small pin punches, etc.) can fit into the hole along side of the drill and remove the pieces as you go along. You will probably have to extend the effective reach of your magnet by holding it to a small gage iron wire and inserting that into the confines of the hole. Using a die grinder in this situation has its own set of shortcomings as the burr will tend to walk off the hardened steel of the drill remnant. George
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