Briggs and Stratton Stuck Exhaust Bolt

[ILENGINE]

yes it will need drilling out but most HHS bits will only dull attempting it. Get yourself one those carbide tip concrete drill bit and drill out the remaining bolt. Then either tap it if possible or drill out for a Heli coil, tTried ap it, and install a Heli coil.

There bolts are usually heat seized and heat harden. Carbide bits are the only thing I found to work reliably for removal.once the bolt is broken off. I even broke extractor off trying to remove these bolts and carbide is the only thing that will cut the extractor out.

Tried that on a bolt I was trying to remove yesterday. This thing ate two concrete drill bits, three carbide burrs, and two diamond burrs($73) in under 5 minutes. Finally removed with a Hi-molybdenum drill bit after about 4 sharpenings. The chips looked like grey iron powder.

 

[bertsmobile1]

Tried that on a bolt I was trying to remove yesterday. This thing ate two concrete drill bits, three carbide burrs, and two diamond burrs($73) in under 5 minutes. Finally removed with a Hi-molybdenum drill bit after about 4 sharpenings. The chips looked like grey iron powder.

Masonary bits should never be used on metals unless the cutting tips are reground to saw tooth profile with the cutting edge leading.
BAck in the bad old days I used to reshape old masonary drills to cut HSS & work hardening steels like digging teeth & plow blades.
Down side is when the tip breaks through the cutting edge chips
Now days there is a plethora of various carbide tipped drill bits
What I have found works best is an end mill but you must grind the end of the bolt dead flat before you start using it.
And of course tilt the drill slightly and $ 20 goes snap .

 

[Hammermechanicman]

I picked up a couple carbide drills thinking they would be good for drilling out broken studs. Nope. They just break easily. I went back to good quality cobalt drills.


I wish LOL

Cleveland 2213 NAS 907 TYPE J Jobber Drill C70367, Right Hand Cut, Split 135° Point, Straw Finish, Spiral Flute, M42 High-Speed Steel - 8% Cobalt, Straight Shank | RSHughes.com

www.rshughes.com

 

[StarTech]

Tried that on a bolt I was trying to remove yesterday. This thing ate two concrete drill bits, three carbide burrs, and two diamond burrs($73) in under 5 minutes. Finally removed with a Hi-molybdenum drill bit after about 4 sharpenings. The chips looked like grey iron powder.

Strange I have been using the same single cut carbide rotary file since 2006. I have yet to find anything that it will not cut. Except it like to try to clog up with aluminum but it is not design to file aluminum, It take a different version for doing aluminum.

And my drill bits usually produce long curly q's, Some are long enough that I have to stop and break them off. Now the rotary file is usually produce fine filings. Those long curly q's does make clean up a lot easier. Those filings from the carbide rotary file causes me to need to dig them out of my fingers and usually requires a magnet to clean them up.

What I have found however is that most bits are rated under 1500 max rpm speed and many hand held drills are faster than the bits rated max speed. This is why most of my electric drill here are variable speed ones. I even have my drill press set at 250 rpm which it lowest speed I can set it at.

Most metals going slow it the key but there are a few where high speed is needed.

I picked up a couple carbide drills thinking they would be good for drilling out broken studs. Nope. They just break easily. I went back to good quality cobalt drills.

And yes solid Carbide drill bits are brittle as heck. They are not meant for hand drills at all and really not for drill presses either.

 

[ILENGINE]

Masonary bits should never be used on metals unless the cutting tips are reground to saw tooth profile with the cutting edge leading.
BAck in the bad old days I used to reshape old masonary drills to cut HSS & work hardening steels like digging teeth & plow blades.
Down side is when the tip breaks through the cutting edge chips
Now days there is a plethora of various carbide tipped drill bits
What I have found works best is an end mill but you must grind the end of the bolt dead flat before you start using it.
And of course tilt the drill slightly and $ 20 goes snap .

The carbide bits also had a steel rating not just for concrete, masonry. The carbide would look like you had chucked it in a drill and while spinning ground it against a wheel, rounded edge.. And any sort of lube turned the powder into valve grinding paste.

I have considered getting some end mill burrs. I think the issue I was having was the material was hard May of been grade 12.9 from what I gathered from other sources. But due to the powdering effect had a clogging effect on burrs.

 

[StarTech]

Ahhh, Those hard metrics are a pain to get out. I haven't tried anything above 10.9.

 

[ILENGINE]

@StarTech Got a new set of stump grinder teeth for my nephews stump grinder a few years ago, and one of the teeth had a burr in the threads. Grabbed a new 5/8 tap and proceeded to run it through the threads. That tooth cut new threads on the tap.

 

[Hammermechanicman]

This is what i use for all broken muffler studs ?

 

[Joed756]

"An entire bottle of pb blaster (not literally but a ton)"

OK, so you quite literally used a ton of PB Blaster, I hope you let it soak in for a day or two. The oxy-torch method is your best best. Good luck.
If you go the route of cutting a slot and using a straight screwdriver, I recommend buying or borrowing a hammer screwdriver and accept that you will only get one or two tries.

 

[granpa49]

Sounds like you've tried just about everything. I think that if there was enough stud sticking out to weld a nut on it you would have already tried that. Even then, you will still have the original problem of the stuck threads. I think that the only option you have now, if you are doing this at home, is to drill it out. Grind it down flush with the surface. This leaves a clean circle such that you can easily determine the center point of the stud. Take a center punch and lightly tap it to make a divot in the center of the stud. Once you are comfortable with the location of the divot, strike it harder to make it larger. Next, take a drill bit that is almost the same size as the base diameter of the stud and drill straight thru. If you have a really good drill press you can place the block in a vise and drill it straight. My drill press wobbles so badly that I could do a better job free handed. It is helpful to brace the block someway, perhaps bolt it down. The objective is to drill out almost everything but the threads while trying not to damage the threads in the aluminum (I assume it is aluminum). Once you have drilled thru the stud, take a pick and start working out the threads. If you are lucky, once you have drilled out the center the outer threads will relax enough to start turning. If it is an aluminum block, the threads won't be bonded to the aluminum and should come out freely. If the block is cast iron you will have a more difficult time with it. If you damage the threads slightly with the drill bit it will not be a problem. However, if you get off center and damage them badly you may have to go the heli-coil route to fix it. If you still have good threads 80% of the way around the hole it will still work. Nothing is going to leak out. One good stud and one questionable stud is better than just one good stud. You asked if you need two bolts. I think you do, but the motor will run with a leaky muffler or no muffler at all. Some motor blocks have the two threaded holes for a flange plus have pipe threads in the hole for a screw in muffler. Or if the hole is round you might be able to thread the inside with a pipe tap and buy a screw in muffler. HF has the large pipe taps. I bought a set. Good luck with it.