Geodesic Dome Struts: Bending

 

Cutting	Flattening	Drilling	Bending

 

Bending struts is a pretty easy step; you secure your strut in a vise or even a slit in a workshop table, then pull or push on the the strut to the correct bend angle.

 

How to set up for a specific strut angle

You can use a simple and inexpensive tool to measure the angle in your setup. An Inclinometer, commonly known as an angle finder can be purchased for less than $15.They are fairly precise, at least for geodesic domes made of pipe/conduit. Note that the yellow angle finder below is used for vertical angles. For both horizontal and vertical angle measuring the digital protractor on its right is the one to use (manual ones are also available).

         

 

Using a stopper for repetitive strut bends

When it comes to angles and bending EMT, pipe or other conduit, the dome itself is very forgiving. For instance your bend could be off by 1 degree but as you complete your structure the metal will bend into the correct angle.

EMT or other types of pipe will bend with not too much effort, although if for example you build a 4V dome you will need to make 2 bends on 250 struts for a total of 500 bends. It seems like a lot but it goes surprisingly quick once you get the hang of it.

To bend many struts quickly use a setup with a stopper block so that every piece will have the same angle at each end of the strut. You will however need to adjust the stopper to each bend angle that needs to be done. If your geodesic dome calculator says you need 4 strut lengths each having different bend angles, then you will need to adjust your stopper for 4 different positions (angles).

If the bend angles are within 1 or 2 degrees of each other, you can average out the value and bend both strut length with the same setting. For example a strut requiring 12.3 degrees and another requiring a 14-degree bend angle can be averaged out to 13 degrees. This will work on simple domes such as the 3V but this does not mean you should be lazy and take shortcuts.

Depending on your workplace you can bend sideways or on top; that really depends on how you can set a stopper block. In many cases pipe is put into a vise and bent sideways because you can attach a stopper to your work table with clamps or nails.

Keep in mind metal springs back a little, therefore you need to position your stopper for a slightly wider angle. Once you have the correct angle you can start bending struts without measuring every time.