On Fri, 26 Mar 2021 05:23:24 -0700 (PDT), Mathew Newton
wrote:

snip

I've noticed that all the manhole covers on our 'new' (2007) estate are made up of two triangles, presumably as each piece is unable to rock regardless how ill fitting they might be/become.

That would make sense and what a good (simple) idea. ;-)

That or some health and safety requirement to minimise weight for lifting them out.

I've seen what look like pretty heavy / thick manhole covers being
lifted one and dragged by a single small (one handed) key, a bigger
'T' bar thing two handed and more of a lever / trolley thing (probably
as the maximum weights thing came in as you say).

I think I've even seen then re-seating them with a big clowns wooden /
rubber mallet thing. ;-)

What I've never seen is anyone cleaning / clearing the frame / cover
before re-fitting but have seen several seeming to have issues doing
so, because of stuff stuck round the joint. ;-(

I wonder if it's one of those things that where in 'most cases'
leaving the crud on means the don't get called back because it's then
noisy? The mud / dirt / moss generally giving enough to allow the
cover to re-seat but keeping the cracks to a minimum?

Cheers, T i m