What tool to use?

Bonnan

Member

Well the NH TC34 has an M16x70 Class 8.8 metric bolt stuck in her. Bolt sheared off, was holding the front under carriage of the backhoe to the tractor frame. I think that's equal to grade 8 bolt.
Any suggestions on how to get the threaded portion out? Not an easy location to access andjust might be a little large for me.
Jim B
 
Best way to get that bolt out is to center punch the end and start a drill in the hole. If you have access to left hand drills they work well and many times the remainder of the bolt will unscrew. If not you can try a square easy out. I have found the best way is just to keep drilling out the remainder of the broken bolt using cutting oil and shape bits. the M16 is a common metric thread. the 8.8 is similar to our grade 8 bolts. I have metrics on my TC34DA. The hole can be cleaned up with a M16 tap. Not an easy job due to location but doable.
 
The Metric or DIN class 8.8 is equal to an SAE grade 5, NOT grade 8. METRIC or DIN class 10.9 is comparable to SAE grade 8.

Instead of asking on here why don't you guys ever search on Google or BING and get correct answers?
 
Being that it sheared off, chances are it will unscrew with minimal effort once you get a way to turn it.

If it broke flush or below the surface, be sure the first thread is not damaged. If it is try to clean it up with a die grinder before you start.

On a bolt that big you might be able to pick at it with a sharp punch, see if it will start turning out. Or try to drill it if you can get a straight shot at it. An easy-out will work on a sheared or snapped bolt, but not on a seized/rusted bolt. If you do use an easy-out, go with the biggest you can get without getting into the threads, proceed with extreme caution. If it offers any resistance to the point of breaking, STOP!

If you are good at welding, try holding a nut over the bolt, weld down through the hole, turn it out. But if in doubt, don't even try if you think you might hit the threads!
 
8.8 is far closer to grade 5 than grade 8 much softer and far less tensil strength. The 8.8 can be drilled easily and the grade 8 is way harder to drill. Jim
 
Thanks, that is what I wanted know. Drilling is about all you can do because of space available.
Jim B
 
So, when its all said and done, I'd be interested to know exactly how you did it. I've used several of the suggested ideas over the years on various problems. I've welded on nuts, cut slots with a hacksaw, drilled and backed out, and in several cases, simply ran it back out with my fingers. Tell me how it goes, please.
 
My left-hand bits must be defective. All but one of them grew legs and ran off. I doubt that one would help with my current broken-off bolt, though, it's a 1/4-20 and left just about one thread above the surface, just enough to grip with my 3" Channellocks--which promptly wore it down to a taper that nothing will grab. And pinched my thumb in the process. I think this one will be ground flush, drilled clean through (about an inch) and nutted on the back.
 
Anyone here watch Fast N Loud? The one episode where they broke a bolt off in the front of a crank shaft and used a metal epoxy on the end of a rod to get it out might work on a bolt that sheared and isn't rusted in place. One day I'll come across a perfect situation to try it. Until then I'll stick to welding on a nut or my least favorite drilling lol. I've found that a carbide bit works well for shaving down that last little bit of bolt left if your slightly off center when drilling.
 

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