"Dave Liquorice" wrote in
ll.co.uk:

On Fri, 30 Aug 2013 13:50:30 +0100, ss wrote:

I have tried a rubber strap wrench that just slips.

How soft is the strap? Tried with a bit of paper between the strap
and the cover?

Anything I could let soak in overnight before I start taking drastic
measures. I have some phosphoric acid, ...

Possibly a bit stronger than I'd like for an overnight soak. See if
you can get some inside the cover down the side of the shaft
hopefully it would make it's way down to the top of the threads
inside.


Reminder - put grease on tap threads when they are new. (But we don't)