The laser cutter I usually use is not available for now, so I had to assemble my project virtually, hence the renderings instead of photos. As an open source project, contribution is welcome and perhaps an interested volunteer with a spare plywood board will test physically and validate my design. ;)
The slots of this design are adapted to a 4 mm (almost 3/16'') thick plywood but can be easily adapted to any size and material, using the plans provided.
If you don't have standardized weights, I made plans for them too. Knowing the density of a material, you can calculate (explained in the last step) the volume needed to obtain grams or ounces, and then cut it with the laser.
Step 1: Materials
- 4 mm plywood board (or plastic) : 37 cm x 44 cm (15'' x 18'')
- 3 small nails (for the pivots)
- material for the weights (plastic or wood)
Step 2: Plans and Cutting
Before cutting, make sure that:
- the size of the slots is the thickness of your material
- the 3 holes for the pivots are the right size for your nail (or whatever you will use)
Step 3: Assembly
Flat parts (the four pieces at each end of the main arm) need some glue; the thinner the layer, the stronger the bond.
Insert nails or any small metal rod into the 3 pivot holes in the main arm.
- The legs are spread and the inserted spacers should stay in place by pressure (press-fit).
Step 4: Weights
Find the density of your material:
Plexiglass = 1,18 g/cm3
Determine how many cubic cm are required for the weight you need:
volume = desired weight / density = 10 g / 1,18 = 8,475 cm3
Divide this by the thickness of available material, to obtain the area to cut:
area = volume / thickness = 8,475 cm3 / 0,5 cm = 16,949 cm2
You can now cut any shape that has an area of 16,949 cm2 and it will weight 10 grams!
It is possible glue pieces together to make other shapes, like cubes.