Removing rounded off / seized hex bolts...

[andyoxon]

Any useful tips / experience on removing stuck hex bolts, before I resort to the hacksaw to remove a stem?

[PaulF]

Can you drive a Torx bit in? And then use that to extract the bolt?

[Jurek]

^ That would probably be my first port of call as well.

[rogerzilla]

You only have to drill the head off.  It may be easier than hacksawing the stem, and saves the stem.

[andyoxon]

Thx.  I tried the torx bit earlier, size below too small, next one too large & didnt seem like it would hammer in - though I could try resting the side of the stem on a large vice & then try.  I have steel drill bits so could try that method.

[Sergeant Pluck]

Drill in a little to allow a screw extractor enough purchase. Or superglue a sacrificial slightly too small bit in.

Even though they have been rounded off, they still won’t have been torqued up that much or the thread would have stripped.

Is this the bike recently in the sales forum? Well bought, if so.

[rogerzilla]

16Nm is normal for a quill stem, which is pretty tight using a normal length 6mm allen key.

[ACyclingRooster]

Hi Andy. Which bolt or bolts are affected and what is access to the heads like ?

[Sergeant Pluck]

16Nm is normal for a quill stem, which is pretty tight using a normal length 6mm allen key.

I am hazarding a guess that it is not a quill.

https://yacf.co.uk/forum/index.php?topic=128487.0

[rogerzilla]

If it's an A-head, it's much easier, then!

[robgul]

I would try the sacrificial Allen wrench but with 2 part epoxy rather  than superglue and giving it at least 5 hours to cure  - the screw extractor idea sometimes works but they are really designed for woodscrews, not torqued up bolts.

Drilling the head of any of the bolts on an a-head stem is not a good idea as it will be almost impossible to remove the remaining bit of bolt.

. . . and if comes to it, man-up and use an angle-grinder - much quicker than a hacksaw!!

[spesh]

The hierachy of stuck bolts 

[andyoxon]

Thanks all.  These are the stuck bits so far...  SP, yes, it's the Genesis CdF

1. Stem - steerer 2/2  & stem handlebars 3/4
2. Mudguard bridge

CdF1 by a oxon, on Flickr

CdF2 by a oxon, on Flickr

CdF3 by a oxon, on Flickr

[Pingu]

File the head and get an adjustable spanner on it?

[Jurek]

If you've sufficient access, then make a dimple in the bolt head using an automatic centre punch.
Once you have a dimple of sufficient depth, repeat the process aiming the punch tangentially to encourage the bolt to rotate.
ETA - I've never known this procedure to fail, I've usually conducted it when the bolt head has sheared and all that remains is a bit of the threaded stud.

[andyoxon]

thx both. 

using an auto centre punch I managed to get a 1/2 turn on one of the bar clamp bolts, but not loose yet.

ETA

OK.  Given that the stem have 5 rounded off hex bolts; I took the decision to hacksaw it off - bi-metal 24 tpi blade made short work.

[Lightning Phil]

Why seized, no grease?

[Sergeant Pluck]

OK.  Given that the stem have 5 rounded off hex bolts; I took the decision to hacksaw it off - bi-metal 24 tpi blade made short work.

That’s what I would have done, as I wouldn’t trust that fork given the demonstrated lack of mechanical sympathy, so would sacrifice it.

The chainstay bridge should be doable somehow, then all that remains to worry about is the rear caliper, the bolts of which the former owner has hopefully never touched, and the mudguard stay bolts. No bottle cages mounted so hopefully those bolts have been left alone two.

Then you will have a lovely frame for not much outlay.

[tonyh]

Just to say: thanks all for another range of valuable know-how and advice!