"Dave Liquorice" wrote in message ill.com...
On 24 Oct 2004 03:44:52 -0700, N. Thornton wrote:

how about this?

make a ladder from 1.5x2.5 planed and 3" screws, cost 8. Now cut it

into say 3 pieces, fitting long meaty hinges like so:

| |
| |
||
| || -- hinge
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|| -- hinge
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| |

Think I'd hinge both sides

I cant work out what you mean there. I did however notice the diagram
came out scrambled - lets try again

_
| | -- wood side of ladder
| |
|_||
| || -- hinge
| |
|_|| -- hinge
| ||
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|_|

and rebate the rungs/steps into the sides a
bit. You don't want a rung to fail and you end up sliding all the way
down breaking each succesive rung as you heavyly land on it.

Well, here's what I was thinking. If you use 2x 3" screws on each side
of each rung youve got protection against screw failure. The rungs on
this design are of 2.5 x 1.5 wood, which is way thicker than
traditional wood ladders. It is important to reject any wood with a
crack in it. I thought those 2 features would be enough to cover it,
but I gues it would take some load tests to check if it does, and if
not, add either metalwork or wood reinforcement triangles under rungs.
What do you think?


If you look at a timber ladder you find every third or so rung has a
1/8" dia wire underneath it this is to stop the run away effect if a
rung breaks.

Right. Commercial ladders are made light though, whereas this design
here has 2 to 3 x as much wood in each rung for simplicity and safety
margin.

It is an interesting idea though. The ceiling below our loft hatch is
the best part of 10' this is out of reach for most commercial loft
ladders.

The one bit I would want to load test before being confident is the
hinge fixings. Due to lever effects there would be very high forces on
hinges and their fixings, and both would have to be very solid. The
unhinged version of this has worked very well for me, but I've not
used a hinged version. The only downsides being that wood ladders are
heavier than ali and not so abuse proof. And must be kept indoors to
avoid rot.

Good luck if you try it

NT