Broken Coil screws

B

Bud57

Forum Newbie
I was taking off the coil to clean the face of it and broke off both mounting screws, anybody have a surefire way besides drilling and tapping--
 
Most they are galled in place but you can try drilling with carbide bit for a twist type extractor. But they usually just break the extractor too or at least that is what happen here.

And what is worst is screws on some equipment have been Loctite in place with red Loctite. I have done several Homelite chainsaws that were done that way from the factory.
 
I grind the top of the post flat, center punch and drill with a 3/32 drill. Then drill and tap 10/32. If it is off center slightly it still works. Don't try to remove the galled bolt. You will do more damage than you can probably fix.
 
I’ve found that before I try to remove the broken screws I do to things. When drilling the screw for a screw extractor I use penetrating oil, like PB Blaster, as a lubricant, which may loosen some of the oxide. Then before I try try to remove the screw, with the extractor in place, I heat the aluminum around the screw with a propane torch to slightly expand the aluminum. Works about 75% of the time.
 
Rivets said:
I’ve found that before I try to remove the broken screws I do to things. When drilling the screw for a screw extractor I use penetrating oil, like PB Blaster, as a lubricant, which may loosen some of the oxide. Then before I try try to remove the screw, with the extractor in place, I heat the aluminum around the screw with a propane torch to slightly expand the aluminum. Works about 75% of the time.
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Similar story here .
I try as per Rivets first but use a left hand drill
About 1/3 of the time the bit bites & screws the broken bolt out
Made the mistake of using carbide ones, does not work has to be HSS bits and if you have the option a sharper point
 
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