I want to hinge an Aluminium ladder at the top so I can swing it up into the loft. This won't be load bearing other than the <10kg weight of the ladder.
The most convenient way would be to drill a hole through near the top of the stiles and use a bolt either side about which the ladder can rotate, but that's a bit crude. While this won't see very much use, it seems that a threaded steel bolt on Aluminium section would be prone to wear and distortion.
Would Nylon bushings/shoulder washers be ok? Or bronze? Or is there something made for the job?
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N
No mail
Use bolts (8 or 10mm, perhaps) with a plain shank and arrange washer shims to make sure the ladder operates on the plain portion, rather than the threaded bit. This will last several lifetimes of loft access provided that it doesn't frequently get wet.
T
The Natural Philosopher
Why not buy a custom made loft ladder?
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S
Simon Simple
I need a 3.5m ladder. The loft is boarded and re-joisted which adds 'thickness' to the floor/ceiling, and the ladder has to land on a landing two steps down from the floor; there is nowhere else it can land. There's no realistic possibility of moving or enlarging the hatch. Few of the many off-the-shelf loft ladders fit all the requirements and those that might are very pricey.
I have a single section 3.5m Aluminium ladder. This is my plan, not to scale...
|X| is the outside wall ### is the loft floor/ceiling below / is the deployed ladder . are hinges, one at the ladder top. This is where the bushings might be. __ is probably 12mm ply, a bit wider than the ladder and 1.8m between hinges. The shorter length is fixed to the floor.
So the ladder top describes an arc. When stowed with the bottom of the ladder on the wall side of the hatch, the ply board is just over vertical. The trig all works out well. Having the ladder stowed at an angle means I don't need so much floor space, and when it's deployed you need a 'corridor' anyway.
A
alan_m
When you pull down the ladder and it drops rapidly (maybe by accident if you are using a tool/hook on a pole) the hinge could be subject to a large dynamic load and not just the 10kg weight of the ladder. If the ladder swings backwards from the vertical as a result the forces on the hinge could be at right angles to the ladder.
You may also need a dampening or arresting mechanism.
My 3 section loft ladder is hinged 6 inches from the top of the ladder but with the hinges* attached to the back of the stiles. The top of the ladder is above the floor of the loft in the climbing position. Attached through two holes in the top of the stiles is U shaped rod (5mm diameter) with the sides of the U being around 600mm long. The top of each side of the U is also bent 90 degrees to to fit the holes in the ladder The bottom of the U section is fixed firmly to the floor of the loft further back from the loft hatch. The fixing of the U section to the ladder and the fixing to the loft floor allows the U section to rotate freely. Its purpose is to stop the top of the ladder moving too far forward so if the ladder drops suddenly when lowering down the top of the ladder cannot swing into the open hatch space (forward of the hinges). While this works with the design and offset hinge arrangement on my ladder a similar arresting mechanism could be fabricated from non-stretching rope etc.
the hinges on my ladder are fairly substantial thermo-plastic construction with the moving part being a thick metal rod between the two hinges. Once when the ladder dropped fast one of them split. It is now repaired with two part epoxy and a metal builders band wrap and has remained repaired for 10+ years of occasional use.:)
T
The Natural Philosopher
Ah. OK
I still didn't really follow that - you need to slide as well as hinge surely? ... BUT can you 3D print some plastic bushings? plenty so if they wear our...
Or...buy some nice pro ones made of zinc plated steel.
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And buy bolts with plain shanks instead of screws.
From deployed, you lift the ladder up. The top describes an arc with a radius of 1.8m as defined by the plywood which hinges up from the floor
1.8m from the hatch. The ladder bottom doesn't hit the wall if you don't let it - you'd keep the ladder in more-or-less contact with non-wall (right) side of the hatch, works out there's plenty of room. If you stow it with the bottom against the wall side (left) of the hatch, the top end is a little under 1.8m above the floor and the plywood is just past vertical.
I know, but the diagrams and trig do work out.
That's a good idea. I was thinking of something like externally threaded tube with nuts, but that sort of hub would probably be better with self-tappers into the Aluminium.
S
Simon Simple
Ah. Got it, I think. Just use a (say) M10 normal nut and bolt through each stile, then screw an M10 round coupler onto the projecting thread. These can then rotate in a hole in the support, which will probably be something like a pair of steel joist brackets, eg eBay 315275562789.
H
Harry Bloomfield Esq
A pair of steel L brackets, one at either side of the ladder. Find a piece of threaded rod, as wide as the ladder, plus some, four nuts and washers. Carve two bits of wood, to make for a tight fit, through the top rung, and drill a holes, to match the threaded rod. Fit heat-shrink tubing shrunk over the thread, to prevent wear where the rod hinges.
T
The Natural Philosopher
Ah. I thought the plywood was fixed. All is clear
Use epoxy as well?
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