On Mon, 15 Aug 2016 16:26:23 +0000, I wrote:

what I still need to check is whether
or not the upper part of the thread engages with the lid itself after
unscrewing from flange.


Sadly, it doesn't, although there may be a gadget that has a slightly
larger screw thread that would grip the side of the bolt hole.
(Or one of those expanding bolts (e.g. Rawlplug) that are inserted and
then
expanded to grip.)
That might be the only 'lifting' solution.

What might do the trick - if it exists - is a lifting spindle with
spring arms at the end, that could be passed down through the bolthole
until it comes out of the lower edge of the lid, at which point the
spring arms would shoot out and provide lifting capability.
But probably not enough clearance between lid and chamber flange for
arms to operate.

No, not enough...

--
/\/\aurice
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