managed to round off a bolt head :(

[montage]

Knees have been in agony recently, so I went out to lower my saddle.
Without too much strain/effort, the allen key rounded off the bolt, making it useless with my saddle being stuck in this position that damages the knees.

LBS job?

 

[Gerry Attrick]

Drill the bolt head off. Use progressively bigger drill bits until the head falls off. It's relatively easy with an allen bolt because you have a natural centre. Just go steady, don't rush the job. Best of luck.

 

[Joe24]

Knees have been in agony recently, so I went out to lower my saddle.
Without too much strain/effort, the allen key rounded off the bolt, making it useless with my saddle being stuck in this position that damages the knees.

LBS job?

Well, gaffa tape wont help you, or zip ties. Hmmmmm..................................

Try putting in an allen key thats slightly bigger then the one you used before.
Or, you might find if you try another allen key, a decent one, that you can just about undo it.
Failing that, get a hacksaw/angle grinder................................

 

[Gerry Attrick]

Ah, I assumed you had the type of bolt head which lies flush with a frame lug. If it stands proud, then cut a lot in the head with a hacksaw and use a flat blade screwdriver in it.

 

[eldudino]

I snapped two bolts off in the frame whilst taking my mudgards off. Start out with say a 3mm drill and work up in increments from there. You need to make sure you drill the thing on centre though, if you're off by a bit it'll cut into the frame which you don't want. A steady hand a keen eye!

 

[Steve Austin]

you can usually drive a torx bit in to get some purchase which will work fine

 

[RedBike]

I wouldn't drill it unless you absolutely have to. If you drill the bolt you have to be VERY accurate or you will also drill something you don't want to.

There are a few less risky options you might want to try first.

If you remove the pressure from the bolt by cutting it in two (if you can get at it). Then it should twist out nice and easily with a set of pliers.

Cut a slot in the bolts head and use a flat bladed screwdriver or if you need more torque a socket set with the appropriate attachment to pull it out.

Get an allen key thats slightly too large (maybe imperial) and hammer it into place. Then undo as normal.

 

[Dave5N]

Grow.

 

[Steve Austin]

you can usually drive a torx bit in to get some purchase which will work fine

what he said

 

[02GF74]

you don't say what sort of clamp it is - either on a steel frame it will be part of the seat tube or a separate, usually aluminium collar.

but in both cases, for the clamp to work, there has to be a gap between the lugs you are bringing closer together when doing up the bolt....... so are you able to get a hacksaw blade or small dremel cutting off disc in that gap and cut through the bolt?

drilling the bolt requires care to keep the drill bit centred, start with small drill, say 4 mm and increase the size until the head comes off or is weakened.

again if you have a dremel you could try making a slot for a screw driver so that the head breaks off.

good luck.

 

[redjedi]

I did that to my seat post clamp.

I took it to my LBS who got it out within a couple of minutes. Not sure what they did, but I assume they get this all the time so know all the tricks.

They even replaced the bolt all free of charge.