Peek the Geek

Well, the good news is I got the piece of wrench out, using a carbide burr. So thank you.

The bad news is the bolt head is damaged enough that an allen will no longer work. Now what?

I appreciate the help thus far.

operator

Drill it and use an easy out. Failing that, drill it the whole way out. Low rpm's and cutting oil are your friend.

dwood

P the G,

Glad you got this far with it!

Does your allen wrench have a nice square end on it . . . to maximize insertion depth? If you can't get a proper-fitting allen wrench to work . . . the next step [if it was in my shop] would be to TIG weld a nut onto the head of the allen screw. This does two things: it gives you something to get a wrench on, and the heat from welding will loosen the screw slightly due to the difference in expansion rate between the two. Once the weld is complete . . . take a wrench and back the screw out. The heat from welding will not be enough to ruin any heat treatment the stem might have.

I realize not everyone has TIG welding facilities at home . . . but you should have a shop nearby. I'm still against trying to drill it out unless you can get a very accurate, rigid setup in a drill press [or mill]. I suspect this is unlikely.

As another poster suggested . . . you might try finding an EZ-out that will fit what is left of the hex in the head of the screw. You might need to grind the length of the EZ-out to get it to a diameter that will lock into the screw. Be sure to wear eye protection when using EZ-outs: they are very brittle and when they snap, pieces can fly off like a hand grenade.

Finally, one last suggestion: since you have a carbide burr now . . . you might try making a slot in the head of the screw, working from the inside of the hex. You don't need to penetrate the OD of the allen screw. Just make two grooves 180 degrees apart, full depth of the hex recess. Then take a large screwdriver and attempt to remove the screw. You might need a wrench assist on the screwdriver to get enough torque.

Good luck!

Peek the Geek

TIG welding would be a very last resort, as I don't have ready access.

I tried just grinding the entire bolt head off with the carbide burr, but the Thomson bolts are strong enough that the burr got eaten up before I could finish the job. I'm not sure what type of burr you use, but I can't imagine being able to carve a straight and narrow enough slot to use a screwdriver. Any chance you could find an image on the internet of the burr you're referring to and post it here?

I'm figuring my next options are:

1. Buy another carbide burr and continue grinding off the bolt head (once the head is gone, the stem should be free, right?).
2. Get an EZ-out and do whatever it is one does with an EZ-out (would the EZ-out be able to cut into the hardened steel bolt?)
3. Drill out the bolt (what the heck kind of bit would I need to drill through an inch of hardened steel bolt?)

What would be my best bet?

As for damaging the stem, I'm not too concerned because the piece that the steerer clamp bolts are in is completely separate from the main part of the stem (see the photo below). And fortunately, I've got another old unused Thomson I can scavenge parts from.

emj2390

put baking soda on the hex head and then crazy glue something to the peice of the wrench like a metal shim or an old wrench then pull the peice out and use a different wrench. baking soda strengthens glue

Peek the Geek

I may try that method if this ever happens again, but I'm well beyond that point now.

BCRider

I wouldn't chew away the whole head. If you do then how are you going to remove what's left of the screw? Unless once the parts come out doing so exposes some of the screw that you can grab with a set of vise grips that is.

If you do try using baking soda and CA glue then be very careful. Especially if it is the thin style. If you over do it, and that's easy to do with the watery consistency of the glue, and it gets into the gap between the head and the stem part then you just lost your chances of getting the screw out. CA glue makes for an EXTREMELY effective thread locking agent. One time when I needed to permanently lock a nut on for a buried install on one of my models I tried this and tested how strong it was. On a clean and degreased screw and nut it was as good as welding. On the #8 test screw I tore off the head and the glued nut didn't budge.

pyroguy_3

There probably aren't threads in the plate that hold the bar to the rest of the stem. To check, take the other three bolts out, and then start spinning the plate CCW to see if it backs the bolt out. If it does, you're done. If not, then you can be assured that grinding the bolt head off will work. If you run out of options, jb-weld the bolt head to the plate and screw it out of the stem that way. You might get lucky and just be able to tap the bolt out of the plate, taking jb-weld with it, and leaving the plate still intact.

Peek the Geek

I just wanted to report back that I freed the stem and everything is back together and as it should be, now. With the hex wrench ball out of the way, I was able to drill into the bolt head with a cobalt bit without having the bit slip all over the place. Pretty easy once I got a strong enough bit and a recess to hold it in place.

I just drilled far enough so that the bolt head was separated from the rest of the bolt, and everything came free.

Thanks for all the advice, and thanks for not busting my balls too much for the initial mistake of not using the right tool for the job. At least now I finally got rid of that 3-way hex wrench I disliked so much.

BCRider

No need to bust your balls. I'm sure you did enough of that already...

I'd also like to thank dwood for the info and advice on the solid carbide burr for this use. I was sure it would shatter like glass for this sort of application so I was a little surprised when you reported back that it had worked well. As they say, we learn something new every day if we are willing to accept it.

dervish

i was thinking about glue...only problem is if u put too much in there u might just get the ball stuck in there more...a risky operation, indeed