Tensegrity Shelf

Having created a set of tensegrity models, what better way to display them but on a purpose built shelf.

But in keeping with the models to be displayed this is to be no ordinary shelf.

This is to a be Tensegrity shelf, employing the same methods as applied to the models.

However, were the previous models have been 3D printed this project is to hand made.

A three tier Tensegrity shelf to be constructed from wood and copper pipes.

So lets get down the to process of making this next project.

Planks (L) 380mm x (W)120mm x (H) 24mm - Qty 3

4mm Screw in ring eyelets - Qty 4

15mm copper earth clips - Qty 8

Copper elbows (D) 15mm diameter- Qty 8

Copper Pipe (L) 35mm x (D) 15mm - Qty 8

Copper Pipe (L) 178mm X (D) 15mm - Qty 8

Copper End caps (D) 15mm - Qty 8

Chain (L) 90mm - Qty 4. Link diameter to suit earth clip screw diameter.

Cord (L) 70cm x (D) 3.5mm - Qty 4

Cable ties - Qty 4

Spirit level

Screw driver, tip type dependant upon earth clip screw head

Cutter to cut chain.

Ruler/Tape measure

Tri square

Pen/Pencil

Drill bit 4mm

Drill Bit 3mm

Forstner Drill bit 15mm

Plumbers Solder

Non Corrosive Flux

Saw

Wire Wool

Blow Torch/Pipe Soldering Iron

Sand Paper

Wood coating - Stain, Paint or Oil as required and as suits ones tastes.

PPE - Associated with the activity to be undertaken.

Dimensional details for the pipes and the shelves.

You will need three wooden shelves with dimensions of (L) 380mm x (W)120mm x (H) 24mm, I cut these from a longer left over piece of decking I had been using to build a fence.

Each of these three pieces needs to be drilled to accommodate the copper pipes and the stabilising cords.

Identify one shelf that will be the middle tier and with a 15mm Forstner drill bit make two holes 15mm deep, diagonally opposite each other in the corners at the intersection of 35mm on the long edge and 25mm on the short edge. Repeat the process at the other location.

Turn the shelf over and repeat the process but ensure that there is no hole directly behind the hole to be made.

These holes are to accommodate the copper pipes.

Next from the corner measure 20mm on the long edge and 10mm on the short edge and at the intersection drill a 4mm hole. Repeat this in each corner.

These are the pass through holes for the stabilising cords.

The two remaining pieces will make up the lower and top tiers but these are only drilled to accept the pipes on one side only.

With a 15mm Forstner drill bit make two holes 15mm deep, diagonally opposite each other in the corners at the intersection of 35mm on the long edge and 25mm on the short edge. Repeat the process at the other location.

Do this in the remaining shelf.

Finally, from the corner measure 20mm on the long edge and 10mm on the short edge and at the intersection drill a 3 mm hole, which is to accommodate the screw-in eyelets. Repeat this in each corner.

With all the drilling complete its time to turn our attention to the copper pipes.

Cut 4 x 15mm copper pipes each 178 mm long.

Then cut 4 x 15 mm copper pipes each 35 mm long,

Ensure that the end of the pipe is not rounded but flat as any slack in the mounting hole in the shelf will reduce the supporting depth increasing any lean.

A pipe cutter is a quick and clean method of cutting but will round the edge of the pipe, this is not an issue for all but the base of the pipe that will plug into the shelf. Either file, grind or use a saw for this part of the operation to prevent this.

If the copper tubes are plated with chrome or some other coating you will need to remove~15mm of this from the end as this will prevent the solder melding with the copper. This can be accomplished with a file, sanding paper or a grinder

Its still recommended to clean and roughen the end in preparation for soldered even if there is no plating to improve adhesion.

Apply a none corrosive flux to the plated free end of the long pipe (178mm), and insert into an elbow joint.

On the 35 mm pipe prepare 15mm on each end for soldering then apply flux and insert one end into the free end of the elbow and on the other end of the short pipe place an end cap.

You should now have an L shaped length of pipe to the soldered.

Repeat the process until you have four L shaped lengths of pipe.

Place the four assembled L shaped pipes on a non flammable surface in a well ventilated area in preparation for soldering.

Using either a blowtorch or pipe soldering iron capable of 400C and suitable PPE.

Heat up the pipes were the solder will flow when in contact with the metal.

If your using solder ring elbows and ends which have an internal ring of solder you should see a small amount of solder appear around the edge when it reaches the right temperature, removing the requirement for the external application of solder.

Once soldering is complete allow the pipes to cool.

Clean any oxide tarnish and flux residues from the surface with wire wool and flush the inside of the pipe with water.

Polish the pipes with metal polish for a brilliant shine.

Select one of the shelves with 15mm holes on one side and making sure these are facing up.

Insert the screw-in eyelets into the four corners.

Insert two of the pipes into the holes to create an inverted L

Take the middle shelf and insert two pipes into the 15mm holes.

Subject to the tolerance of the drill the pipe may be marginally loose though once assembled the pipe will not fall out. However, if too many degrees from the vertical its less aesthetically pleasing and also more difficult to align vertically. This can be resolved with a wrap or two of tape around the pipe circumference, glue, strategically placed screw or an internal plug.

Turning the two shelves on their sides longitudinally facing each other with the pipes overlapping.

Cut 9cm of chain and on either end loosely fit a copper earth clip.

Slip a clip over each short length of pipe on each pair of pipes.

Take a length of cord (if synthetic heat each end, if none synthetic a little glue), to prevent fraying and make it easier to pass through the holes securing it to the eyelet with a knot. You need a knot that can be adjusted.

I used a Cow Hitch/Lanyard Hitch*

This and further knots can be viewed here: Animated Knots (No affiliation, feel free to view this or any other site.)

Put the cord through the hole in line with the eyelet in the middle shelf.

Repeat for all four eyelets and holes.

Push the two shelves towards each other to create tension in the chains whilst tying Overhand knots* on what will be the top of the second shelf.

Readjust the knots at the eyelets to pull the Overhang knots* close to the shelf surface tensioning the cords and chains to apply equal tension at each support point.

Insert the two pipes in the 15mm holes in the top shelf and place on its side longitudinally directly opposite the middle shelf.

Fit the 9cm length of chain with the earth clips to the shorts pipes as before.

Repeat the process for the other two pipes plus chain.

Tie the cord to the eyelet with a Cow Hitch/Lanyard Hitch*.

*These could be different knots from the ones I chose for his project.

Repeat for the remaining eyelets.

Readjust the knots at the eyelets to tension the cords and chains to apply equal tension at each support point.

There should now be sufficient tension to stand the completed shelf up with the shelves horizontally.

Using a spirit level on the bottom shelf ensure this is flat use this as a reference for the other shelves.

Place the spirit level on the middle shelf and adjust the knots on the eyelets on the bottom shelf do this in combination with the clips on the short shorts by sliding them forward or back, until the shelf is level and the front on the shelf is level with the front of the shelf below it.

Place the spirit level on the top shelf and repeat the levelling process by adjusting the top knots in the eyelets in conjunction with the clips on the shorts pipes as per the middle shelf.

Secure the knots at the eyelets with additional knots or with a small cable tie do the same on the bottom shelf.

Assembly is complete.

The last part of the make process is to apply some sort of protection to the wood.

The protection could be an oil, vanish, stain or paint.

I applied a stain followed a light hand sanding then Danish Oil which gives more of a sheen than a shine.

But apply whatever suits your tastes.

Now that the work is done its time to both display it and make use of it.

Hope you found it interesting.