Technical frozen busted 5/16 bolt HELP

ok , both bolts on my cracked thermostat housing broke of . got one drilled out where a bolt goes in . BUT ,on the second one my drill bit snapped off . i cant drill it out now because the drill piece has ate more bits than i can count. not real easy to get to . sure hope some good advice /suggestion is out there . what ya got ? thnx for any help

 

Safety gl***es , small punch and a BFH .
Can you place a nut over the bit and mig or stick weld the nut to it ? Let everything cool down to where you can touch it then try to twist it out . You may want to heat up the drill bit red a few times to remove its hardness . Good luck there’s no easy way

 

Yes your best bet is to weld a nut onto it.
The heat will help and take a candle while its hot and push the wax into the area. It’ll seep into the threads.

 

I also have good luck with welding a nut to a broken bolt. However, be sure you have a good supply of nuts. It may take 5 or 6 before the bolt comes out. Never found one I couldn't get out with this method.

 

bolt is now below flush . i should have tried the heat still might but id hate to crack the head its a good running /6

 

The bolt is made from different material then the cast iron head . It is smaller than the head and will get hotter faster than the head . But I’m no expert.
Maybe it’s time for a blown hemi to be mounted in the bed . Then you could easily work on it

 

broken drill bits are almost as bad as broken taps.
welding a nut to hardened steel can make things worse.
hammer, punch, needle nose, try to knock it loose and back it out, and try not to damage the area any more than necessary.
I know, not much help but keep at it, you'll get it.

 

no one makes a drill bit that will drill a bit ? i never tried heat to soften the high carbon . red hot for a second , slow cool should do it ?

 

I think I would use a 1/4 or MM
$15 ish
Fabrication hole cutter style its hollow so you are cutting bolt & little of intake.
Then use time sert style thread repair
Or tap 1 size up sae / mm

 

aint my first rodeo , but ive sure been thrown many times .

 

Grind it out with a drimal and a several grinding bit . I’ve removed small taps with an engraving tool before. There’s no easy way or one sure way to remove the drill bit or bolt . You just got to use every trick in the book sometimes.
If a torch isn’t an option , due to flammable materials close to it . Try to find an electric heat induction tool . I’ve used those before with good success

 

I've seen guys blow them out with a cutting torch, but that's not a skill I possess...

I've bit the bullet several times and pulled heads to take them to a machine shop.

 

so ive never used /heard hougen tool . we think it can eat the bit . i think it was 1/4 or smaller china steel .

 

very last resort . but how would they do it ?

 

There good option for many uses beside
just cutting a hole ,
I have many, some 5 inch long up to I believe 3inch OD
It will straddle & cut bolt @ same time

 

Well, one place I used did the torch trick but it's definitely not as easy as he made it look. I did note that he used a very small cutting tip so that's at least part of the trick. But I tried that at home (using a few 'practice' heads) and just made a mess.

The other place milled it out with a Bridgeport using a reverse-twist end mill bit.

 

i tried looking them up but couldnt see anything that small

 

@buick bill
ROTACUT™
https://hougen.com/product-rotacut-cutters/

you can buy individual or kits

 

If you can find a place that does EDM removal, but you would probably have to remove the head.

Phi

 

The Hougen bit MIGHT be able to cut the pieces of drill bit out but you would need to put it in a mill and at that point just use a carbide bit. There is no way you will be able to do it with a hand drill and not walk all over messing up the hole more. IMO.

If you know someone decent at TIG, I've had the best luck just building up the top of the broken bolt and working it out with vice grips.

 

@Bentrodder
Some time you need to look @ different ways ,
Depends on your skill you can do with out the guild / center point ,
or use a another guide, a plate with a hole of ID of OD of cutter .

sorta like using hole saw to cut a bigger hole thats already cut , 2 hole saw one inside of another .

I think off different ways to do things
Like use my Mag drill on wood , plastic
Aluminum

 

You got a welding machine? With the machine off and a piece of 1/8 E7018 in your electrode holder, put the end of the rod directly on the drill bit. Turn the machine on and you'll get heat at the drill bit. When the 7018 turns red, it will have welded itself to the bit and bolt, turn the machine off and cut the welding rod just above the cast iron. Use a fresh stick of welding rod and do it again. Slip a nut over the cut off ends and weld that to the rods. Turn it out. Do it right and you won't have melted metal all over the place.

 

EDM / spark erosion?

 

maybe, then use a left hand drill bit

 

You mention the housing is cracked. Is the bolt below flush with the block or below flush on the housing?

 

I have so many ways I do ,
I use Left hand to drill & creat heat @ times act's like easy out .
To me L-H 2 tool's in one

 

Is the thermostat housing aluminum?

 

You didn’t say how much of the drill is in the hole. If it’s anything more then just the tip you will probably not have much luck chipping it out. If you already have a broken bolt and now a broken drill you need to stop before doing any more damage to the head.

Your chances of removing the broken drill even with a carbide drill are very slim doing it free hand. The hole will just get oblong/oversize as it slides around in the hole on the broken drill. You might have a chance setting the head up in a Bridgeport with a carbide end mill in a rigid setup.

I think the most likely fix is finding a machine/tool shop and removing with Electrical Discharge Machining ( EDM). Probably will not be cheap and if hole is already oversize probably at a minimum need a HeliCoil but probably an insert. There are numerous styles of inserts.

 

Yes, I saw an article in a magazine, they were removing a broken stud from a rare engine block. Cost was not an issue. According to Mr Google cost are now between $75 and $500 depending on the shop rates and setup times

Phil

 

im planning on a heli-coil if i can get there . im in about a 1/4 now . need another 1/4 to make it good . in answer to a previos question the housing is cast . not sure why that would matter . its removed . and i had a replacement . ordered carbide bits ,5/16 , but i canceled . im thinking i better try to get 1/4 through first . not pulling the head..... yet . if i give up i do have another head that i believe is all good . could already had it swamped if id admit failure . but i hate to admit defeat !