Molding a stair rail.

[jhewitt]

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

[jhewitt]

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

[SonomaProducts.com]

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.

[Morris Dovey]

| 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

[A. D. Coby]

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.

[Mike O.]

When we do this in new homes we screw clamping brackets to the existing treads (or to temp treads if finished treads are to be used) to which we then clamp the bending rail. This gives you the radius and correct rise to match that particular stair. We use 10"x10" metal L shaped brackets that have a stiffener welded at an angle between the legs. The problem with bending rail with a rake is that as you clamp up the rail it needs to twist as it rises. Your not only gluing the pieces together while making the bend you also have to have enough pressure to actually put a twist in the rail. It takes a lot of brackets, clamps and glued up fingers.

Mike O.

[jhewitt]

Thanks to all for the info and suggestions. Mike O's idea appeals to me the most - because it's simple enough for me to understand!!

I can weld up brackets, and buy more clamps. However, the stairs are finished, they are built from masonry / bricks, with marble treads, wooden nosing's and terra cotta 'like' tile, risers. I don't see how I can clamp anything to them, without damaging them.

Need to regroup and ponder - over a glass maybe.

Thanks aga>On Thu, 21 Jul 2005 17:20:49 +0200, [e-mail] wrote: >

John Hewitt, Malaga, Spain

[Mike O.]

Since your run is only about 6' you might be able to cheat and use a flat bend. You might try to make a template out of something that will stay flat, maybe 1/4" plywood or even a stiff cardboard. Lay it on your treads and scribe it to the wall. See how that lays on your treads while avoiding the temptation to push the ends down. My guess is that as you hold the template down to the noses, on the middle couple of treads, the template will be a little high at both ends. If that amount is not too great (no more than 2" or so) you MIGHT be able to live with it. If the template (laying flat) is close enough, you could then just glue up a flat bending rail off-site. You can use the same technique mentioned before but just screw your brackets to a wood floor somewhere or to a piece of 3/4" plywood. You might be able to get by with plywood brackets (since the bend is flat) but that will depend on a lot of factors including thickness of the strips, species and how much pressure it takes to bend all of the strips at one time. Another thing to be aware of is that you will want to bend on the inside of your arc. That arc will need to be smaller than your template by the distance to the center of your bracket (from the wall) plus 1/2 the thickness of your rail.

Mike O.