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Archive for February, 2010

Building a Curved Stair

February 17th, 2010

This is an article that is not really about stair software but a visitor on my blog asked about making curved stairs. I have developed several techniques for different types of curved parts, cut strings, closed strings and handrails according to whether they are flattish, molded round etc.

Here’s the way I make a curved central cut string.

Note that although StairDesigner helped me set up the general lay out, the working drawings were drafted by opening the StairDesigner DXF files in Autocad.

Most of my curved strings are built using a technique I developed that I’ve called laminated layers. In fact to get the curved helical shape I glue together curved horizontal parts cut and calibrated from a flat board.

Here’s a photo of the  cutting and  calibrating the curved parts.

cutting layers on the band saw

cutting layers on the band saw

calibrating ont he spindle moulder

calibrating on the spindle moulder

These parts are drilled and dowels used to reinforce the laminated assembly and stop slippage while gluing.

drilling layers for dowels

drilling layers for dowels

Note how I use the calibration template to precisely position the holes.

This photo shows how I glue the layers together using the dowels and template to align them.


Gluing the layers

Gluing the layers

For convenience I glue the parts together in blocks that are the height of one rise, and then assemble the blocks. This enables me to cut the helical under side with a saber saw.

Cutting the lower helical surface with sabre saw

Cutting the lower helical surface with sabre saw

I then assemble the blocks on a floor plan making sure everything is lined up with a laser plumb line.

Blocks assembled with laser plumb

Blocks assembled with laser plumb

Once the string assembled I glue  laminates on the layers to give the  string it’s finish.  To glue the face laminates I use some special clamps.

Gluing laminates

Gluing face laminates

gluing laminates on the underside of the string

gluing laminates on the underside of the string

This stair goes up into a circular stair well, here’s the stair well assembled inthe workshop:

Circular stairwell

Circular stairwell

Here’s the curved string with the stair well assembled in the workshop:

string assembled with circular stairwell

string assembled with circular stairwell

And here’s the stair assembled with it’s center post and steps in the workshop:

Completed stair in workshop

Completed stair in workshop

And from underneath:

curved stair in workshop

curved stair in workshop

Hope this has been of interest to you.

To see a few stairs that have been build using this technique visit my web site at :

http://www.ntdesigns.org

If you would like more information on how to use this technique or on any other of my stair building techniques feel free to contact me.

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