Drilling out JB Weld from exhaust bolt thread?

[AMK]

As requested, pictures of the dilemma. First I will recount what I think I did wrong. I believe that in drilling out the old thread and what remained of the old bolt I wasn't perfectly straight and more than likely attempted to thread mostly aluminum and some remaining steel. I meant to say I used a 17/64 bit. So now I am faced with a weird spot. Do i try to continue to tap what I have, I am about 3/4 the way tapped. Or should I drill out larger to 3/8 and attempt to tap that. Hmmmm.

Here is before I started tapping, you can see the old threads, maybe this should have been my indicator to not proceed yet.


Here is where I sit now, the tap is broken flush after I attempted to use pliers to back it out.


Well a learning lesson for sure, unfortunate it had to be so deep. Won't let this keep me from my third week of may deadline!

Definitely a learning experience.
If you hit the bottom of the hole that tap will be pretty tight. At this point the tap extractor that gsrick mentioned will be your best bet.
Apply some heat from a torch to the material around it, not too much and from inside the exhaust port.
Get the extractor as deep in as you can and carefully try to work it out then in then out a little at a time till it's loose.
Be careful because the extractor can break too. Vise grips at the hole on the extractor and a tap wrench at the top will give extra grip and stability.
Get some good cutting fluid in there as well.
As Chuck said, make sure you can get as many shavings out as you can first.

[hillsy]

At this point I think i would sacrifice a pair of needle nose vice grips and grind them till I could fit them down the flutes. Clamp onto that tap and use an adjustable Crescent wrench on the flat of the vice grips to turn the tap..again blow the chips out with the compressor and squirt lots of oil into the hole. Keep alternating with the air and oil to keep the chip build up to a minimum.

Even needle nosed pliers would work ok - as long as you "tap" them into the flutes they should hold enough to back out the broken tap (fingers crossed).

After that, if you have enough thread, Loctite a stud in there to mount your exhaust and call it done (actually, use studs on ALL the holes).

[chuck hahn]

At this point I think i would sacrifice a pair of needle nose vice grips and grind them till I could fit them down the flutes. Clamp onto that tap and use an adjustable Crescent wrench on the flat of the vice grips to turn the tap..again blow the chips out with the compressor and squirt lots of oil into the hole. Keep alternating with the air and oil to keep the chip build up to a minimum.

As requested, pictures of the dilemma. First I will recount what I think I did wrong. I believe that in drilling out the old thread and what remained of the old bolt I wasn't perfectly straight and more than likely attempted to thread mostly aluminum and some remaining steel. I meant to say I used a 17/64 bit. So now I am faced with a weird spot. Do i try to continue to tap what I have, I am about 3/4 the way tapped. Or should I drill out larger to 3/8 and attempt to tap that. Hmmmm.

Here is before I started tapping, you can see the old threads, maybe this should have been my indicator to not proceed yet.


Here is where I sit now, the tap is broken flush after I attempted to use pliers to back it out.


Well a learning lesson for sure, unfortunate it had to be so deep. Won't let this keep me from my third week of may deadline!

[chuck hahn]

I agree on Timeserts. After using them I will not ever do helicoils again.

HI Kodak , hope you get it out , if you do , look in to time sert , not helicoil , I did my head and sparkplug holes . makes a much better job ,Time-Sert 1812 M8 x 1.25 Metric Thread Repair Kit on ebay #282289364765 they have all sizes that one is just to show you , where helicoil will pull out these will not ,

[gsrick]

I'm having trouble posting images, but if you scroll to the bottom of the page you can see it is designed to work even if it is broken down in the hole.

http://www.metalartspress.com/howtos/removing-frozen-or-broken-fasteners

[chuck hahn]

Maybe if the taps not broke off down a hole. Think he said his broke off below the surface.

[gsrick]

This tool may work. http://www.waltontools.com/products/extractr.htm

[chuck hahn]

Or a modified pair of needle nose pliers down the flutes?? Lots of air to flush the chips out, some oil, and maybe get lucky to get the tap to move??? Snap ring pliers may also reach maybe???

[gsrick]

Well I took a stroll up **** creek today. Got a nice 7/16 hole drilled. Started tapping with a 8mm 1.25 tap, got about 5/7 of the way maybe 13/17 or 17/21, take you're fractional pick. Met some resistance, haven't tapped a bunch before so I don't know how much torque is too much for knowing when to stop and reevaluate. I know to one turn quarter turn back. Well she snapped like a dry branch. Flush break. Can't get a grip on it. Most of the tap is in there. Any thoughts? Should I buy a Walton extractor and try that??

Damn that sucks, The taps are fluted so the shavings have a place to go, can you get a fine point punch on one of those and work it back out tapping it around or are the flute to deep? pACE3-997626dt.jpg.

[chuck hahn]

weld may not stick to the carbide taps. He may well be screwed now. Guess he can at least give it a try though. First I would get an old tap and try welding to it on the bench to see if it sticks rather than waste my time down on the head itself.

[Buffalo Bill]

I take my MIG welder and lay a fat spot weld on those broke exhaust bolts. The weld will not stick to the head and it hurts nothing. Let the first fat spot weld cool and do another right on top of the first. Repeat the process till there is enough past the head surface to grab with vice grips. The heating and cooling of doing the series of spot weld help crack the corrosion seizing the bolt too.

Oil the crap out of it with your fav penetrating oil and start working it back and forth to use the threads to grind up the crud in there. Youll soon see its getting easier and easier to move the stud...then slowly start removing it ..work back and forth and be patient.

This method might work for you.

[AMK]

Well I took a stroll up **** creek today. Got a nice 7/16 hole drilled. Started tapping with a 8mm 1.25 tap, got about 5/7 of the way maybe 13/17 or 17/21, take you're fractional pick. Met some resistance, haven't tapped a bunch before so I don't know how much torque is too much for knowing when to stop and reevaluate. I know to one turn quarter turn back. Well she snapped like a dry branch. Flush break. Can't get a grip on it. Most of the tap is in there. Any thoughts? Should I buy a Walton extractor and try that??

Did you mean 17/64 drill? Did you get all of the bolt out or did you drill and tap what you had?
Your hole was off center and if you left part of the bolt in then you were trying to tap part steel and part aluminum.
I think the part steel then came loose and jammed against the tap and broke it.
Send us a picture so we can see where you are now.

Had the same problem only I didn't snap the tap off. Another thing that can help is heat and cold, metal is very conductive and therefore sensitive to temperature changes. If you can't drill it out then try loosening it with alternating heat(aka blow drier) n cold. Retapping a bolt is such a pain and requires lots lots lots of patients . I feel for ya, good luck