Removing a seized fork cap

Nearly a year ago, I was struggling with a seized fork cap which wouldn’t come out no matter how much heat and hammers were applied.
I worked around the issue by buying a new cap, and using spare parts from the copious stack accumulated over 40 years of LC ownership.
(Link to blog entry)

Time has passed, the initial build of the project bike is completed, but the stuck fork cap has been weighing on my mind.
Clearly, I need to apply pressure from below… more than the spring entombed within can apply.

My initial thought was to drill a hole in the cap, thread it for a bolt, and pull the cap out.
I’m sure this would have worked, but I went for something more ambitious.
I wanted to push from the underside.
The problem is that I could only fit a 6mm piece of bar through the 8mm threaded hole in the bottom of the fork stanchion… and I thought that a bar so slim may bend and make matters worse.

Eventually, my though processes turned to the threaded hole itself, so I bought a meter length of 8mm studding.

I screwed this into the bottom of the stanchion, and ran it up the 70cm length to the top of the stanchion with an electric drill.

Once it was butted up against the cap, I removed the drill, and gave the end of the exposed stud a tap with a rubber mallet.
…and the cap popped straight out!

It may have taken a while to think of a solution, but lateral thinking wins the day.
The cap is in such poor condition I would have had to buy a new one anyway. The rubber o-ring is nowhere to be seen. Possibly a consequence of the heat and hammers approach originally tried, but I would have expected to see some remnant, other than the greasy black detritus which came out with it.