Removing snapped drill bit ?
 

If anyone has a solution to removing a snapped drill bit from a cylinder head ( done while trying to tap out an already snapped bolt ) = I'm all ears.

Happened on a 4hp outboard - an OLDIE but a goodie..

Is there a drill bit that will drill through the snapped drill bit so I can then re-tap the hole ??

you might have to go at it with a dremel. then get a timesert kit and your good to go.

Depends on hardness and size of the bit that broke. I've used a smaller cobalt bit to start hole on the broken bit or bolt, and then used a screw remover bit and wrench to remove bolts and bits alike - but its a pain. imagine a cylinder head hole is probably 3/8" or so, so that's an advantage over something smaller. dremel with a diamond tip would probably start the extraction hole better than a even a cobalt drill bit. Good luck, sounds like a PITA..oops 4hp bolt might be a bit smaller...

Thanks guys - I like the dremel / diamond bit. I'll try it ! Totally PITA. 1972 !!!! 4hp evinrude - runs like a top for the 1 hour used seasonally when the wind totally dies on my day sailor.

It was running HOT when I went to winterize it - I had just replaced the impeller last year so I figured I'd check the cylinder / exhaust plate for blockage and gasket issues. Snapped bolt on inspection. All was OK in there anyway !

Dropped the lower unit. Turned out that the copper tube feeding the powerhead and fed by the impeller housing was clogged ! Straightened a hanger, unclogged it - but now this snapped bolt is allowing exhaust plate to leak !

Aaah tinkering. But, I figure even a pro would have had that same thing happen too. Wife thinks I'm insane. I try to explain, some guys watch sports or do crossword puzzles - I fix things ! You should see my fully restored 8 hp 26" snowblower ! I'm sick - I know !

I've be told an important reason for changing your impeller every year or so is to keep the lower unit bolts from corroding and snapping. Go figure.:( good luck tinkering

Used the diamond dremel - it did not cut but a benefit is that it loosened the bit and I was able to fish it out while twisting with two straightened dental picks.

Then I cleaned the hole with a tungsten bit. All tapped and done...

Thanks guys !

Glad to hear you got it taken care of without too much trouble.

You know those breaks can be hell. Lucky it was a bolt that snapped in a spot that the powerhead didn't have to come off to access it ( like 3 of the 8 are ) and that it was loose enough to get out that bit out. Otherwise I would have been in trouble.

Thx again.

When I break bits, I use a punch and hammer it into pieces to remove it. Less risk of damage to threads.

I spent about 35 years developing new jet engines that run so hot that conventional anti seize products don't work; in fact they would oxidize and actually make the problem worse! Other than heat and/or liquid nitrogen, and Zyglo fluid (used for florescent penetrant inspection), this is some of the best stuff we found: http://www.kanolabs.com/google/ Good hardware stores sometimes carry it but you can also order it from Eastwood http://www.eastwood.com/kroil-penetrating-oil.html

oh yea, that is good stuff. I have used it at work and home and it works quite well.

I'm in the lighting repair business --shopping center and such pole lights If all goes well we only need to service a fixture every 3-5 yrs and have found a old electrician wire lube (slip stick) made from bees wax to work remarkably well for getting the screws loose after going thru numerous heating and cooling cycles . Boss asked me yrs ago what the hell I was doing with it all --told him and he tried it on his boat found it worked better than anti seize on every thing from the prop shaft up! I think 3m is now making a product know as well

the heat seams to cause the wax to wick up the bolt threads

The problem we had was that virtually any organic material we used as an antigallant would turn to carbon at 1200-1400F and become gallant . . . a pretty effective thread locker! The results are similar to the aluminum oxide that forms from galvanic action around steel bolts in an aluminum outboard! Grease or Tef-Gel works by insulating the dissimilar metals to prevent galvanic action and works well if it doesn't get too hot. The Kroil seemed to penetrate on a microscopic level. A colleague who had a side business overhauling turbochargers found that using Kroil was the only way he could get them apart, and he got Pratt to start using it. The use of heat and cryogenic liquid nitrogen also created enough relative motion between parts to help it work even better.

I agree. Kroil has no equal. We used it on a turbine powered boat. Things get hot and salty and generally stuck on a boat with gas turbines.

Awesome guys ! Thx. I'm going to find me some Kroil or order it because ' an ounce of prevention is worth a pound of cure ... '

Well Honey is the perfect food.

Oh yes it does!!!!

Whitmore,s

This product beats Kroil hands down!!

Make note: D665 (Seawater)

Right now Kano labs is running a 2 for 1 deal. Looks pretty good.

http://www.kanolabs.com/google/

Best stuff I've found so far. It works!