[Shayne]

In most instances this wouldnt be a big deal, either drill/cut the head off the bolt or slot it for screw driver removal. But alas the bolt with rounded out allen hole is located inside the BB shell of a Fisher CR-7. One bolt was partially stripped but I was able to pound a slightly larger english allen key into it and remove it that way. But bolt #2 looks like it will be a permanent fixture rendering me unable to disassemble the frame.

 

[vdubbusrider]

soak it, drill a hole in the center of the bolt and use an "easy out" tool. as long as you use a quality "easy out" they work well. pretty cheap too. (is this possible in the space you have?)

i've also given completely stuck bolts to machinists and had them drill the bolts out with precision and still save the original threads.

 

[Shayne]

Pretty Tight Confines

I was going to check out the "easy out" tools this afternoon. Not sure if it willfit in the space I have.

If it were to be drilled out it would have to be by a machine shop. There is 0 room for error. The 5mm allen wrench barely fits through the access hole. and due to a somewhat poor design you cannot access the bolts by going through the sides of the BB shell.

 

[ssmike]

Long shot, but can you drill a hole into the bb shell from the front side (straight line into the bolt head)? The front triangle is aluminum, so there probably isn't much space on the bb shell that isn't covered by down tube or weld. If you could drill into the shell form the front, in-line with the stubborn bolt, you might be able to drill all the way into the bolt and drill it out. This will be an interesting exercise.

 

[Shayne]

There are exixting holes

..in the front to allow you to install/remove the bolts. They are just big enough to get a 5mm allen key through and smaller than the bolt head that needs to be removed. I'd rather not inlarge the hole. But that may be the only way and would make the removal relatavily easy after that I think.

Unfortunately I dont have a pic of the problem area handy. That would clear things up a lot.

 

[ssmike]

..in the front to allow you to install/remove the bolts. They are just big enough to get a 5mm allen key through and smaller than the bolt head that needs to be removed. I'd rather not inlarge the hole. But that may be the only way and would make the removal relatavily easy after that I think.

Unfortunately I dont have a pic of the problem area handy. That would clear things up a lot.

I'd try to find the longest 1/8" drill bit and try to drill the bolt out. It sounds like it's already trashed so ...

 

[tlg]

In most instances this wouldnt be a big deal, either drill/cut the head off the bolt or slot it for screw driver removal. But alas the bolt with rounded out allen hole is located inside the BB shell of a Fisher CR-7. One bolt was partially stripped but I was able to pound a slightly larger english allen key into it and remove it that way. But bolt #2 looks like it will be a permanent fixture rendering me unable to disassemble the frame.

Try a torx bit. Sometimes with striped out allen heads you can jam (or hammer) a torx bit in and it'll grab hold.

 

[BadHabit]

In most instances this wouldnt be a big deal, either drill/cut the head off the bolt or slot it for screw driver removal. But alas the bolt with rounded out allen hole is located inside the BB shell of a Fisher CR-7. One bolt was partially stripped but I was able to pound a slightly larger english allen key into it and remove it that way. But bolt #2 looks like it will be a permanent fixture rendering me unable to disassemble the frame.

If you will be using penetrating oil, use "B'Laster"--seems much better than others. Soak and be patient.

Other remedies I have not used: valve grinding compound in the bolt head to grip a brand-new wrench; steel wool in the bolt head for same purpose.

But soak soak soak.

 

[loonyOne]

Well, I was/am not familiar with the CR-7, so I looked one up at FirstFlightBikes and get the jist. Yes, not much room to work with there. The ideas listed above/below are good ones, especially the Torx bit idear. It really depends on how comfortable you are in your mechanical abilities...there are a number of ways I would try...

You may want to try a small block of dry ice and while holding it with something that is not going to freeze your fingers off, hold it against the head of the screw for a bit to 'shrink' the screw. Not too long, because it will eventually tranfer the cold to the aluminum and shrink the threaded hole as well.

Buy a left-handed drill bit just smaller than the threaded portion of the screw. Should be somewhere near 1/8". Sometimes the friction required to drill, coupled with the soothingness of heat, will begin to back out the screw...or at least loosen it enough to get it started on the reverse.

Don't know how much room you do have, but have you tried getting a pair of ViseGrips onto the head of the screw?

I would assume that the screws used had some potion of LocTite on them, so you may want to try some solvent from the reverse side to loosen the LocTite.

When I posted about needing some mounting screws for a Judy XC brake arch, I had been in your position...the heads were stripped out and I virtually had ZERO options. I ended up buying a carbide, die grinder bit (the rounded cone shape) and ground the head off the screw until the brake arch was free to remove. I then used a pair of ViseGrips to easily remove the remaining screws. This stuff will make you grow old sometimes. I wish you good luck Shayne! Let us all know what ends up working for ya.

 

[Shayne]

Problem Solved....Finally

Ok, I had to drill out the bolt head as none of my "easy out" bits was long enough to reach it. And of course the bolt is stainless so it took a while to grind it down.
With bolt head removed the chainstay section came off pretty easily and I was left with a little piece of threaded rod which screwed out without issue with the help of a little penatrant.