In message , Theo Markettos
writes
Bit of a long shot this one, but...

I'm looking at designing a spiral staircase (for a new-build). For various
reasons it needs to be possible to separate the floors the staircase links,
so I'm thinking of having a trapdoor that fits into the gap in the ceiling
formed by the staircase. The door would be hinged and counterweighted, on a
pulley controlled by a handle somewhere, tight fitting and fairly heavy (for
sound and thermal insulation), with a bolt to lock it. It wouldn't be moved
very often (once a week maybe), otherwise staying fixed open or fixed closed.

Think Bond, sharpen the edges of the staircase, attach multi-horsepower
motor to the top and turn on, staircase augers down into ground opening
up a very attractive 'rustic' well, the addition of a few strategically
placed sharks with lasers and you've achieved not only your objective of
separating the floors, you've also got a nice focal point.

All silliness aside, I *have* seen this sort of thing before with the
trapdoor, I'm sure you'd find similar arrangements in old Windmills and
lighthouses but I think you'd have to build some sort of separate guard
around the top to stop people falling into your shark filled
pit^H^H^H^H^H^H down the stairs. If it's only moved every now and then,
what's up with a removable floor section that can be stored somewhere?
Thanks
Theo

--
Clint Sharp