Introduction: Tensegrity X Module
This Tensegrity X piece is based on one made by Kenneth Snelson 1948. It uses waste wood and demonstrates the concept of 'floating compression'.
I first came across Tensegrity some years ago when I saw a line sketch in a book called 'Innovation and entrepreneurship' and wondered how it worked. This led me to making what had been described as a 'Tensegrity Mast' - where 2 'Vs' are attached perpendicular to each other and then suspended one above the other. The lower 'V' supporting the higher one.
I made my first prototype out of bamboo and the next one out of wooden dowel. When assembling the second one I released it could be stringed together in such a way that by pulling on the lower cords, the 'mast' would raise up with each module being raised by the one beneath it. I thought this might make for a variable central table support.
I learnt this didn't work as hoped. The tension in the lines only become taught when the 'mast' had been fully extended outwards. This was due to the cords basically forming a hypotenuse of a triangle (i.e. the long side) when collapsed down, as the tower extended this was changed into becoming the other 2 sides of a triangle and hence tightening up.
Some years after making the Tensegrity mast I learnt the credit for the original form lied with Kenneth Snelson's X-piece. Making this Tensegrity X is a small tribute to him.
The height can be adjusted as described in step 7.
Supplies
Some waste wood
PVA Glue
Cord
Eye hooks
Paint
Tools:
Drill
Saw
Mitre box
Step 1: Mitre Box
I found some waste wood on the side of the road which had formed an 'A' shape. It had probably been used in a stand of some sort, but no matter. Once I got it home, I dissembled it and kept some of the fittings and screws as I figured I could reuse them.
My mitre box needed to be reassembled. I used a couple of the screws from the disassemble wood to fix it. Then I made a couple of diagonal cuts into one of the pieces of waste wood halfway through its thickness. The plan was to make a kind of cross. You will get the general idea by looking at the photos.
Step 2: Making a Cross
I made some diagonal cuts into another piece of wood about halfway through its thickness. Then using a chisel like tool (Screwdriver) and hammer, a notch was made. This was 'mated' with the other notch in another piece of wood to form a cross. Three vertical crosses were made and one horizontal one.
Step 3: Make a Base
A base was created by making a horizontal cross. I cut it ends to a bevel for aesthetic considerations. Then I attached a vertical cross to it to form a base which will support a cross suspended above it.
Step 4: Wood Filler
As I was using recycled wood, I noticed there were some holes which required filling in. I did this by stuffing in a little bit of newspaper, adding in some PVA glue and sprinkling on some of the saw dust which had been created from the previous sawing. Once dry, the surface was sanded smooth with sandpaper. I also rounded off the ends of the crosses.
Step 5: Painting
I decided to paint the X Module to be of a similar colour to the original one. To save money I got a 200 mil 'sample' pot tinted 'Rustic Red'.
Step 6: Assemble
The base was assembled using PVA glue and some of the fastening which I had found with the wood.
The vertical crosses were glued together with PVA glue.
I fitted some eye hooks to attach cord which suspended a vertical cross over the base.
The assemble X-module looked similar to the original one created by Kenneth Snelson. But I noticed his had some lines going around the outside. These looked to be 'excess to requirements' as the cross join was securing the cross together. But in fact, the outer lines can form another tensegrity in their only right. This has inspired another tensegrity model. Stay tuned.
Step 7: Adjusting the Height
To make the height adjustable, string the pieces together so the second member is pulled up by having cord from the bottom of the second member, over the top of the first and through eye screws at the bottom of the first. By pulling on these cords the second member raises up. More cord from the bottom of the second member to the base is used for stability along with cord from the middle of the second member to the top of the first member. A third member can then be supported above the second member in as similar way.
The cords are secured to the eye screws using a 1/4-inch bolt with washer and nut. Tightening the nut secures the cord while making it adjustable to tension the cords or to change the height between members.
The tensegrity I made used 3 X members and reached 6 feet tall. It could be used as a coat stand and would also make for a good passionfruit vine climber.