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removing sheared bolt with drill bit stuck in it


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water pump bolt sheared off. right angle drill and started drilling the center of it out. drill bit sheared off inside the bolt. can't really see or get to what's left of the drill bit.

 

now what? generic off the shelf sears drill bits.

 

i'll try extracting the drill bit, but i'm thinking i might have to drill around the bolt to get it to come out. i have a spare bad block to experiment on to make sure i don't hit a water jacket or something. many tiny holes all around the bolt until i can wrestle it out.

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*whistle*

 

Man that's gotta hurt.. :-\ I'm trying to think of some options, but there aren't many coming to mind. If you try drilling again, I might recommend using some cobalt bits instead of generic ones - hopefully they won't snap on you.. Also - try to use the largest bit you can - less chance of snapping. ;)

 

Good luck!

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i didn't think about larger bolts not breaking, good point....for next time!!!

 

i was wondering if maybe some high-end drill bits would blow through this off the shelf sears craftsman drill bit. i think i might buy a few highstrength bits.

 

any ideas what the strongest drill bits are? cobalt it is?

 

machinist friend for the NIH dropped off a pair of needle nose pliers that are microscopic thin that he made just for extracting very tiny sheared off drill bits. but i doubt i'll get the remnant out....other options will be needed.

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Eek no fun,

I had this same problem a few years ago in the rear end of a truck with a left hand drill bit. After talking to many knowledgeable guys at the hardware store I ended up using 2 of these special coated titanium(or was it diamond tipped?) bits to be able to drill through the other bit. Not sure if that's exactly what they were but a few minutes (like an hours lol) of drilling with them and it came out with the broken bolt, they were super expensive bits though..in the range of $35, meant for drilling through super hardened steel. Not sure if that helps at all but any good hardware store should know what you need to drill through that other drill bit. I would at least try and drill it with a cheap bit just to see if it doesn't come loose first.

I've also had sucess using my dremel with a grinding bit to knock loose broken off easy outs (will never ever use those things again, of course we all know that).

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i'll try extracting it for awhile, but $35 times a couple is fine by me, if i can find them. i'll look around for sure. i plan on having this car awhile so a few dollars is no big deal. i'd rather drill through it than peck around and try things i don't know will work or not.

 

agreed on ez outs, they suck hardcore. up there with snake oil in my oppinion.

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Damn. It's hard as hell (but not impossible) to drill another bit. Even if the one you are using is harder, it will want to walk off of the broken bit. I would do this: Place a small nut over the broken bolt/bit and weld the center of it up. It may wind out. It has saved my hide several times in the past on VW engines.

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dude...don't even bring up welding. that's how i ALWAYS do it. works every single time...now i can't say that any more. i tried 6 or 7 times and the weld would not hold. couldn't figure out why it wouldn't work this time. it's like the bolt didn't want to take a weld? tried a few different strokes and grounding the nut and bolt, nothing would work. not enough left to weld on now.

 

GRRRRRRRRRRRRRRRRRRRR

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Maybe pull the engine for better access, or the radiator etc. on the front end. If this vehicle is a keeper, invest some time as well as money into it. Using that right angle drill, with harder bits, sounds like a good way to break even more drill bits.

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i didn't think about larger bolts not breaking, good point....for next time!!!

 

Actually, I was talking about a larger bit - small bits easily snap, so if you can get a larger one going, it's less likely to break on you.

 

And as far as I know, cobalt is the hardest drill bit you can buy. Though maybe something with diamond would be available, and obviously harder. Let us know what you find, b/c I'm quite curious.

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Just as a tip on the "weld the nut on" trick. Builod up the center of the broken bolt to about 1/8 to 1/4 above the surface then set a washer that has a slightly larger center on this and weld it on (center only) then put the not on top of the washer ond weld the center of the nut to the built up area and tack the nut around the edge of the washer. Put as much heat as the nut will take without melting when welding the center. As it cools let it get to orange or slightly cooler ( not black ) before using a wrench on it. The washer gives you more weld to work with and doesn't shear off the bolt as easy. I have even gone as far as to shot it with PB as it cools.

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If you end up having to cut out the bolt, get a piece of steel tubing just larger than the bolt and a couple inches long, take a file and cut some serrated teeth into the end of the tube. Chuck it into your drill and cut around the outside of the bolt.

 

One thought on the broken bit is to ruin its temper before trying to drill it.

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Matco Tools sells L.H Cobalt drill bits . But you have to remove the broken bit. Or you will break the cobalt bit . Try heating the broken bolt and use some bees wax instead of penatrating oil . Use wax when bolt is hot . Also heating and cooling the bolt helps . Cool bolt with ice water from a stream of a squirt bottle .Try removing when bolt is cool and Aluminum is hot. Try this I have a few more tips if this does not work, but think it will. Don't give up !

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i'll be doing this tomorrow, i'll let you know how it turns out.

 

i'm wondering if the bolt was stainless steel or something else that didn't take to my wire feed welder? the weld broke loose very easily. no matter now, i really don't have enough material to work with anymore.

 

i'll try extracting the remainder of the drill bit first so i can continue drilling. after that not sure....looks like i have a few options. that steel tubing bit for cutting out the bolt sounds crazy...i like it!

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that steel tubing bit for cutting out the bolt sounds crazy...i like it!

A little "cross-pollenation" from the world of wood working. It is a common method for removing screws from wood. There they use brass tubing, available in many sizes from hobby stores. Brass might work for you, too, but the aluminum may be a little too hard for the brass. (Though oak and maple can be pretty hard, too.)

 

Good luck!

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If you use the tube cutter what size hole will it make ? I think the bolts are 6mm.If you have to completly drill the bolt out it can be repaired with a heli coil.If you use a oversize bolt the water pump mounting hole will need to be drilled out. I would try to keep it the original size . Good luck

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hmm how good are you with a torch??? If you can get a small enough flame on a torch to just get the bit red then tap the oxegen the bit will explode but would be real hard to do on aluminum(in fear of melting the aluminum away). Done it on cast iron before, other then that i would have to try and work the old bit out with a center punch or something like that. Everytime i tried to drill a bit out i broke one of my cobolt bits off in the hole so be carefull and goow luck

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Okay definetely dont try and drill it out any more. cobalt, titanium it doesnt matter these are all just slight variations of your sears High speed steel bits. heat and welding are your only options. you wold be surprised at how accurate you could cut out with a torch. the only problem is the melting temp. of your HSS bit is quite higher than the bolt your trying to remove and the surrounding metal.

 

HSS can have the temper removed by quenching it quickly with water. good thing is you will be removing the temper of both the bit and the bolt and the nature of the High speed steel it will become much more brittle than the bolt only if you get it cold quick but if you try and weld it after good luck it wont stick. I would exhaust all your welding choices first. if not you can take your time and chip the HSS out that has been untempered with a small tool prick punch or center punch. its going to suck no matter how you look at it.

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what a job this turned out to be. 2 hour timing belt/water pump/oil pump/seal job turned into a marathon.

 

titanium and cobalt bits did nothing, noone had diamond tipped bits but i can't imagine they'd last long enough to do anything. this bolt was HARD. i suspect the last time a water pump was done the person replaced the bolt with something else...stainless steel bolt or something because it was hard as crap to drill out. and i bet that's part of the reason it was seized in place as well, material. and i bet that's why my wire feed welder couldn't weld it very well....maybe the material would have been better with higher end welding.

 

the steel tube cutter was awesome but wouldn't work because by the time i made it the bolt was already flush to the motor. so it was hard to get started perfectly, when i started cutting with it i ran into part of the remaining bolt somewhere and by then the groove was made and i couldn't get it to track without hitting the bolt. i should have used this method first when part of the bolt was still remaining. once it hit the bolt the steel would widdle away immediately, but cut the aluminum great.

 

i continued drilling and took out a large swath on the "outside" of the bolt. then knocked it until it fell out of that area i drilled out. i had a bad block in my garage so i made sure to drill an enormous hole on top of that hole and check for any coolant passages. luckily there's nothing even close. in the end it left enough threads to put a bolt in but reduced some of the sealing area for the gasket. but all the gasket mating surface bewteen the bolt and coolant is fine, only the very outer edge of the bolt was drilled away. been driving it and so far it's fine.

 

thanks for the help guys!

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