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gumbellion

Broken Bolt. Help Please

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I put the flywheel cover on my 426 and all the bolts torqued to 10 newton meters. After I initially torqued all the bolts I double checked them and the bottom left bolt could be turned but then the wrench clicked. Then I decided to triple check all the bolts and this time that same bottom left bolt snapped off.

Its one of the bolts that has the hollow pin for lining up the cases and the bolt snapped inside the recessed area where the threads start. I drilled it with to what I thought was probably sufficient for the easy out with a 5/64 bit which the #1 (under 1/4 diameter bolts) easy out called for. When I turned the easy out it busted too. Right where the broken bolt begins.

So now what?? Any serious suggestions will help. I think i might be able to drill beside the chunk of easy out thats in there but I would hate to put myself in a worse position. Or else i could maybe take my bike to a machine shop in the truck and see what they can do.

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Or else i could maybe take my bike to a machine shop in the truck and see what they can do.

That's where you are with it at his point.

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machine shop will have to use an end mill to get that ez-out removed. i hate when ez-outs break - they are much harder than most drilbits so drilling them out is a difficlut process - hence the endmill bit inthe bridgeport machine.

maybe they have a trick up their sleeve. please post your outcome.

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I called today and asked the guy at the local machine shop what he thought. He said ill have to bring it in for him to take a look at. He says hopefully he can do it with the motor still in the bike, if not then ill have to take the motor apart and take him the piece of case which will suck. I wont get the bike there until next Monday due to work but hopefully im in your prayers guys. And i will definitely post the outcome and cost involved.

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If I were you, and removing the so called "easy out" was the main concern, I would take it to a competent welder and have him weld a nut onto the easy out.

I have done this numerous time and it works great. Even if the easy out is broken off 'in the hole' (not flush, but actually below the surface). a decent welder, using a ' gas lens' if needed will have no problem getting that out.

This has become my primary bolt/easy out removal method over the years. It's not really very difficult at all.

BTW, end mills are not made of 'unobtanium' they are made of the same material as drill bits and if all things are equal, they will cut through (or not cut through) the same materials as a drill bit (made of the same material).

They (the machine shop) might use EDM if they have it and it works great also, but call a 'competent' welder first. Probably cheaper and faster.

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If I were you, and removing the so called "easy out" was the main concern, I would take it to a competent welder and have him weld a nut onto the easy out.

BTW, end mills are not made of 'unobtanium' they are made of the same material as drill bits

He is talking about a screw extractor broken flush at the bottom of an 8mm deep 8mm hole. You know someone who can weld onto that?

End mills are also available in carbide.

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He is talking about a screw extractor broken flush at the bottom of an 8mm deep 8mm hole. You know someone who can weld onto that?

End mills are also available in carbide.

As a matter of fact I know of at least 4 or 5 that can do that without even breaking a sweat.

I did this one this morning and it took all of 5 minutes, and I am only considered a hobby welder. It is quite easy and this one I did without a gas lens.

This site has drills designed to drill out taps and easy outs. You need to take your time and use a carbide burr to get a flat spot or the drill will tend to wander and ruin the hole. HERE

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I called one of the shops before work this morning and he said they could probably do almost exactly what you did. some welding technique until it was out far enough to put a nut on it. tomorrow morning im going to take the bike in and they are going to give me their thoughts. wish me luck

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I worked at a machine shop for a few years and did a fair amount of bolt extractions. We also had a great welder on staff that got a lot of guys out of a jam.

But I have never seen a technique as trick as usmcpaul just laid out!!!!! similar but not as cool.

I would think worst case scenario after that procedure a thread repair might be in order

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I worked at a machine shop for a few years and did a fair amount of bolt extractions. We also had a great welder on staff that got a lot of guys out of a jam.

But I have never seen a technique as trick as usmcpaul just laid out!!!!! similar but not as cool.

I would think worst case scenario after that procedure a thread repair might be in order

Thanks for the compliment, but I can not take credit for originality on that, it was taught to me by a very good welder years ago.

And you are correct, I generally run a tap through it just out clean out the threads.

This technique has one other benefit to it that I forgot to mention. If you can get the tungsten close enough to heat the tap/easy out, but don't have room for the filler rod, you can anneal the tap/easy out enough to drill it.

I know annealing is a much more complicated process than just heating and cooling and hoping, but in general you can anneal the piece that needs to be drilled and make it soft enough to drill.

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As a matter of fact I know of at least 4 or 5 that can do that without even breaking a sweat.

I did this one this morning and it took all of 5 minutes, and I am only considered a hobby welder. It is quite easy and this one I did without a gas lens.

This site has drills designed to drill out taps and easy outs. You need to take your time and use a carbide burr to get a flat spot or the drill will tend to wander and ruin the hole. HERE

Forkpics001-1.jpg

Forkpics002-1.jpg

Forkpics003-1.jpg

Forkpics004.jpg

Forkpics005.jpg

Forkpics006.jpg

Nice job!:worthy:

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Well it sounds like im boned. I went to the 2 machine.welding shops in town and they both told me that it would be a minimum of a couple hours labor ($100/hr) and they cant guarantee that they will be able to remove the bolt without screwing anything up. The joys of living in a small hill billy town aren't all they cracked up to be. So I'm looking at a new left half of my crank case which will be less money but more labor for me.

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If you lived in a big city, more welders would be available to do your job, but they'd charge $120/hr instead, and still guaranty nothing.

Crankcases are sold only in sets and should not ever be mixed. This is because the bearing and shaft bores are cut with the cases assembled to assure absolute parallelism between the two sides.

I would think some form of repair attempt would be worth making, but it's a tough call.

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I am glad you told me that you should never mix cases. I shot off a few e-mails to guys in the classifieds section so I will see how that pans out. Maybe something will turn out in my favour. If not a new set of cases is $500 which would be a tough bill to swallow since i just spent all my bike fund money on a cr500. Regardless i will have to get it back together since my yz is a street legal supermoto and is normally my primary mode of transport in the summer.

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Get that thing EDM'ed. A good operator will burn both out and you will still have the original thread. Look for "broken tap removal". There is a guy that does it here in SoCal. I realize you are not from here. But if you are going to split your cases anyways, you may want to ship it to him. Thats if you can't find anyone around your neck of the woods. There is a minimum charge, like 50 bucks. This guy has burned out some 6-32 taps for me a bunch of times.

Not that I break very many taps........:worthy:

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How close to the Blue Water or Ambassador bridges are you? I live in Macomb Michigan which is about 45-60 minutes from either.

I forgot to mention that I also have a small machine shop in the basement, so as a last resort I (just in case I can't weld onto it) we could mill it out. I don't have any carbide tooling, but there are plenty of tooling supply centers around here. A carbide end mill would cost you about $30, but we can cross that bridge if we come to it.

If you can get it to me I will gladly give it a try for free.

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Get that thing EDM'ed. A good operator will burn both out and you will still have the original thread. Look for "broken tap removal".
That's become more affordable/available now, has it? If so, it's the trick approach to the problem, no doubt. A 6-32 tap is about half the size of the 6mm bolt we have here, and much harder. :worthy:

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