Stem bolt seized and now nicely rounded off, thought I might drill it out but my drill bit is hardly even scratching the surface.
Suggested remedies please?
We hammered a torx bit on where the allen key should of been. Came out safely after that.
remove other bolts and cut bolt flush with plate and remove stem cap and bars. I would then use a hacksaw to cut a groove in the stump and remove with a screwdriver
I would use this as a last resort technique though and try the torx bolt one first tbh.
Undo other bolts, see if you can relax it (I'm assuming there's a bar fitted but with the other bolts out you might be able to push the stem plate back over the stripped bolt. Might get grips on it or crosscut it for a screwdriver. And yep torq but sounds like you might be past that- the trick is to stop as soon as the bolt feels weakened rather than fully rounding it, keeps the options open.
Better drillbit! Can you get at the other end of the bolt? The advantage of that is that it's spinning the bolt out as well as drilling so with the heat of drilling you may get a response.
Also, real penetrating oil. PLusgas is good, even GT85 is pretty effective. Give it time, soak it if you can.
Which bolt is it? The one that clamps the faceplate onto the bars or the one that clamps the stem onto the steerer?
It's the bottom of the two stem to steerer bolts. It was rusted inside the Allen key bit hence why it just rounded out so quickly.
Cheers I'll try the torx bit first.