Molding a stair rail.
 

I want to build a handrail for the stairs in my home. The stairs it
will compliment curve over a section appx. six feet long as they rise
to a small landing [ which is perhaps why no handrail was ever fitted
]. The rail will have a cross section of minimum two inches square, so
I think I shall laminated the rail - to substantail to bend. I hope to
use pine wood 8mm thick; because that's avaialble in the stores here
as T&G flooring.

I can work out the radius of the rail as it follows the wall just by
making a takeof from the wall. What I can't picture is the second
radius that has to be molded in to accommodate the stairs as they rise
a total of appx. six feet. I have to hold the wood laminations as they
glue in a compound curve.

I'm sure this has all been done before [ or figured out ], can anyone
point me in the right direction for some info. Please.

Thanks.

John Hewitt, Malaga, Spain

Let's see... it's been a long time and I always do it with CAD now. You
are esentially slicing through a cylinder at an angle. That is an
elipse if memory serves. It's a parabol if you slice through a cone.

Anyway, it will take someone with good geometry skills or a CAD system
to lay out the elipse. Then you want to plot points along the elipse on
a grid, mayb 6"x6" or 3"x3" so you can transfer it to a layout table.

If you could give me the radius and angle of rise, I might be able to
get a few minutes in front of the CAD system and bang out a layout for
you.

SonomaProducts.com (in
) said:

| Let's see... it's been a long time and I always do it with CAD now.
| You are esentially slicing through a cylinder at an angle. That is
| an elipse if memory serves. It's a parabol if you slice through a
| cone.

It may be a helix - in which case the radius remains constant and the
height changes at a constant rate as the angle increases/decreases.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html

It may be a helix - in which case the radius remains constant and the
height changes at a constant rate as the angle increases/decreases.

I was watching an episode of 'This Old House - Classics' and they had a
tour of a company that made spiral and curved stair cases. The stair railing
were made of laminated pieces. To get the proper curve for the railings,
the company had a series of open framework cylinders for jigs. There were
different size cylinders for different radii of stair cases. The rise of the stair
case was laid out directly on the cylinder. The strips of wood were glued
and then bent around the cylinders and clamped in place. The open framework
of the cylinders was necessary since it allowed attachment of the clamps.

Even with slow setting glues, speed was important since there many pieces
of wood to make even a modest sized spiral railing.