mnmkpedals 

A while back I picked up a rough Cannondale ST400 frame and fork to build up as a basic tourer for a friend. Just now getting around to breaking down what little is there and realize I overlooked the fact that the hex is stripped out (clearly someone was trying to get it out for a while) on the quill. Is there any other way to remove it? The stem isn't stuck (loose enough to turn some if I hold the front wheel/fork steady and turn it), but it does seem there might be a good distance to go with getting it out.

Hoping there's some method you all know of for dealing with stripped hex?

Dave Cutter

Use an easy-out screw extractor.... many different styles, brands, flavors, and prices. Basic idea is the same: Hard metal edge cuts into the screw when turned left.

SHBR

There are many methods, don't expect it to be easy though.

Just a quick search brings up this: (for a motorcycle part, however the same methods may work)

https://answers.yahoo.com/question/i...2212128AAdXvfM

oddjob2

If you can twist the quill, then turn the bike upside down, squirt some pb blaster down the hole of steering tube and wait overnight. You should be able to twist it out by morning.

mnmkpedals 

Ok, just "blasted" it. Trying that first since I have it on hand. Will let you know how it works in the morning. Thanks!

If no luck, will try #1 above...

72Paramount

I would weld a hex wrench to the bolt and then twist it out. But that's just me.. Odd jobs suggestion is a good one. You can also drill out the top of the bolt which would release the stem as well.

Prowler 

I recently had this on a 70s Peugot sumptin-or-nuther - hex key hole all rounded out. No metric or fractional key would fit and get a grip. Too shallow for an easy-out. I was surprised how easy it was to drill out. Just be real careful as you go so you drill thu the head which releases the bolt. Avoid drilling into the stem though you may just a little. The head should spin with the drill bit as soon as it releases.

On the one I had the head of the bolt was about twice as long as others I've seen so we drilled down far enough to get and easy-out into the whole and just spun it backwards. BTW: about a week before that I had flipped the bike upside down, removed the front wheel and blew Liquid Wrench spray down the tube and let it soak for a week. May have helped.

likebike23

If the stem is nothing special and you don't care about destroying it, you could cut through the quill and bolt just below the extension. The quill would just slide out if you grab it with a vice grip. The expander bolt could then be worked out. I know it's not the most elegant solution, but won't cost a dime if you have another stem lying around. Note: if the stem is slammed you probably shouldn't try this.

oddjob2

After you get the quill part way out, assuming the hex bolt moves a tad too, one you have about 3/8" showing, you should be able to grab the bolt head with vise grips.

miamijim

As mentioned above...

A. Weld a hex key to the bolt.
B. Cut through the stem and bolt as high up as possible.

I dont own a welder so I'd opt for 'B'.

Reynolds 

Welding would ruin the stem. I'd rather grind a small chisel and force it into the hex recess, then turn with vise grip. The bolt probably isn't too tight.

72Paramount

Most of my chisels cost more than even the best stems out there. And welding to the bolt ruins nothing. Remember, the bolt is already stripped!

Centaurious

Use a cutting disk on a Dremel to slot the allen head, drive a dime into the slot and turn with vice grips.

davester

The screw extractor idea is the most straightforward and shouldn't damage the stem. Available at any hardware store.

Reynolds 

I was assuming an aluminum alloy stem with recessed bolt. If you can weld an hex wrench there without ruining the stem, then you're a Master Welder! And you don't really need a chisel, an old 1/4" or 5/16" drill bit could do.

mnmkpedals 

Score one for power tools. The Blaster didn't do a lot to loosen it, and already having a larger enough metal drill bit on hand, I just drilled out the top of the bolt head. As Prowler (thanks!) said above in #7-- it was remarkably easy. Once I hit the bottom of the head, the stem just popped right out and I pulled out the remaining part of the bolt. Thanks to you all for the great advice.

79pmooney

Maybe I am not seeing this right. Why can't the OP simply drill into the hex socket with a bit just bigger than the bolt? The hex socket should do a good job of centering the bit. Drill carefully and stop just as the gap starts to show at the bottom of the socket. Now tap the bolt down with another bolt or whatever and a hammer just like one would with a good stem. Remove stem as usual. With care the only damage will be a little scarring of the bottom of the bolt recess in the stem, something you will never see once a new bolt is in.

The OP can start with the Easy-Out approach. If that doesn't work , he can go on as I suggest. This seems awfully simple, Is there a reason it won't work? Actually, if the hole is misdrilled for the Easy-Out, it could both damage the stem a little and make centering the approach I suggest harder and possibly risk the punch slipping, doing more damage. More reason to start with that larger bit and drill once.

Again, I welcome reasons why this won't work. Edit: didn't see Prowler's post. Great minds?

Ben

Lascauxcaveman 

When I had this problem, I dug into my big box o' surplus hex wrenches (where do all these things come from?) I found one that is whatever the non-metric size up from 6mm is and refaced the business end of it to fit. On my bench grinder, I ground down all six faces of the hex wrench so it tapered down just a bit and then pounded the wrench into the mangled recessed bolt hard enough to basically reshape the thing to a new size. The bolt is actually still usable, though I doubt I'll ever put it back on a stem.

Spierce4337

Currently got the same problem on a Merckx MXL that I'm restoring. Attached is a photo (frustratingly, because I've got less than 10 posts I'm not able to post a photo).

Given that the bolt is rounded and effectively useless, I figure drilling out as the OP did would probably be the best solution.

Just wanted to inform the community to build some testimony for this method. Will let you know how it goes.

oneclick 

Sometimes all you need is to grind the end of a key the correct size flat. Many keys are not flat, and anyone ham-fisted enough to round out the hex socket may well have not had the key all the way down in the hole. There is often enough of a hex at the bottom for a flat-ended key to grip, if firmly seated.

Iowegian

Drilling it out should work. Drill slowly with a good quality bit and use plenty of light oil and you should have the head off in no time. The drill bit should be slightly wider than the shaft of the bolt but small enough to not hit the stem.

Spierce4337

Thanks lowegian. Having only a 6 and an 8mm bit, I started with the 6 (hex head was 6mm too). When I realised that wasn’t going to work I moved up to the 8.

After only a couple of minutes and a bit of kickback from the drill, the head sheared right off, leaving the threaded length and the expander still inside the stem (I was lucky here as the bolt was aluminum and not steel. I assume steel would take a bit more time with the drill otherwise).

I then proceeded with a punch and a hammer on the remaining bolt length and expander, which dislodged to the bottom of fork steerer. The stem was still stuck though.

A few hours and two good soakings of WD40 and I started to get some movement in the stem. After working it side to side a bit, the stem came free.

I took a few pictures of the whole process. I’ll post as soon as I can.

+1 for drill method.

jackbombay

Aluminum stem bolt? What kind of stem? Can you check the remaining piece of the bolt with a magnet?

scarlson 

My favorite trick was always to hammer a Torx bit or Torx socket of the appropriate size into the offending allen head. Often this way the bolt can be reused - it's just Torx head now!

Spierce4337

Yep, just checked it. Definitely aluminium. Its a 3T Status stem.