The malheur happened when I fastened two of the up to now temporary fixed stanchions with brass anchor bolts.
In a first step I drilled oversized holes in the sheer-clamp and filled them with epoxy.
In a second step I screwed the anchor bolts to the stanchion bases for exact positioning. Then I pluged the stanchion bases with the bolt-on anchor bolts into the epoxy-filled holes.
The plan was to remove the screws in a third step after the epoxy has cured enough.
But the plan did not work. The Epoxy was already too strongly hardened when trying to loosen the screws. I had to remove the stainless screws somehow by drilling. But normal HSS drill-bits failed. The drills-bits were blunt after a few turns. After I bought special cobalt drill-bits I had a little sucess.
Now I could remove the stanchion base but how should I remove the glued brass anchor bolt?
I had the idea to build a hole-saw from a piece of steel pipe (outer diameter 10 mm, inner diameter 8 mm). I rasped some tooths to one end of the steel pipe and could sucessfull remove the glued brass anchor bolt.