Good evening

Taking apart an old suspension fork

need to detach the legs from crown

I got one leg off

the other legs one more screw to go
but the screw is completely stripped

my allen key will not grip as inside is all rounded
outside the grips are gone too
how to i remove this screw without damage to my crown

i really need to get rid of this screw
thanks

You should bring down a sample allen bolt screw to the hardware store, and ask for help with a screw extractor bit or set of bits. These are spiral tapered bits that have a left hand screw thread pattern. A small set of 4 bits isn't very expensive, less than $15 at my local OSH or Home Depot. You'll need a carbide or hardened bit to drill steel. and if you don't have one, a manual driver bit holder. Make sure your bits don't have a long unthreaded point, since this is a stripped allen hole that won't be very deep.

1. If there are other screws that support the fork blade, put them back in, snug but no too tight. Do this only if it will alleviate shear or load on the stripped bolt.

2. You're likely to need to drill the top of the allen hole deep to get enough bite. But just try the extractor bit first by hand to see if it fits in the allen hole and is deep enough to bite. If not, then prepare to drill deeper. Drill a smaller hole than the diameter of the allen. Too wide and it could cut the head of the bolt off from the main shaft and damage threads and hole on the fork. Drill about 2 mm deeper.

3. Use hand tool force only if you can, and stick the extractor bit into the newly drilled hole turning counter clockwise, The extractor should tightened and the bolt should finally loosen. Try not to use a "power" tool, which is likely to strip the hole futher.

4. You'll need to replace the bolt you just destroyed with the extractor.

How about using a dremel to cut a slot across the head of the nut and use a flat bladed screwdriver to remove.

The screwdriver slot trick might work. I actually tried it on a derailleur pulley allen bolt not too long ago. I got lazy and didn't clamp it down. The slot was lousy and didn't grip well. I ended up having to drill it out and replace the bolt. But if someone has a jig to hold the dremel in place so it doesn't skip, then sure, that's a great idea.