This may have been mentioned before on the forum, I saw this tip somewhere but can't remember where (this happens a lot lately) My A7 plunger crank had the plugs centre punched in two places and I was dreading the removal with all the trouble people have with this task. Firstly I drilled a few thou in the centre punched holes to ease removal. Then I ground a 1/2" flat wood drill bit to fit the slot exactly so it was nice and tight, (keep the bit cool so it does not soften it, I mounted the drill bit in my drill press (pillar drill)
I clamped the crank to a block of wood with a large hole which took the crankshaft ends allow it to sit level, bringing the wood bit down to the slot and locked with the drill stops, I used an adjustable spanner to urn the drill bit and bingo, no heat needed, no swearing but two re-usable plugs. Hope this helps someone, as I said not my idea but it works a treat.
