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If all you require is a cardboard model, then the tools can be as simple as a pencil, ruler, compass, adhesive tape and a box knife. In what follows I assume you want to construct larger objects out of panel material such as plywood, particleboard, MDF (Medium Density Fiberboard), flakeboard, blockboard, or solid wood planking -- the prefix ‘Ligno’ means ‘woody’. However, the material could equally be Perspex, polystyrene foam, Hebel, aluminum, or any other panel material, that is capable of being accurately cut to precise angles.
For laying out the faces of medium-to-large objects you will need a steel ruler at least 60 cm long and an accurate beam compass (also known as a trammel). The illustration shows a telescoping beam compass I made from 20 x 12 mm Mountain Ash (Eucalyptus regnans) and a set of Kunz® trammel points purchased from the Australian woodworking tools supplier CARBA-TEC®. The wing-nut clamps and fine adjustment screw (made from threaded rod and hex nuts) allow precise distances to be quickly and easily set with the help of a steel ruler. An elegant but somewhat expensive beam compass made by Veritas Tools® of Canada can also be purchased from CARBA-TEC®. The fine adjustment mechanism on a beam compass makes distance transfers quicker and more precise than with a ruler and pencil alone.
You will also need some means of ‘rough-cutting’ faces from the panel material, prior to precision trimming. The illustration shows hexagonal faces being rough-cut from a MDF sheet using a Black and Decker Scorpion Saw. This has the advantage of being able to easily start a cut in the middle of the panel material (as can a jig saw). However, there is nothing wrong with an old-fashioned hand saw, and it’s good upper-body exercise as well!
The ideal tool for precision trimming of faces is a bench-mounted circular saw with a traveling table on which the work is clamped. The bad news is that commercial ‘panel saws’ are expensive, heavy, and take up a lot of room. The good news is that you can make one quite cheaply using a good-quality portable saw and some siding door tracks. The main requirements are that the work must be able to pass through the saw along a perfectly straight line (or vice versa) and that a mechanism is needed to precisely align the work so that a thin pencil line is split in half by the subsequent saw cut. Also, the tilt of the saw blade needs to be easily and quickly adjusted.
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The illustration shows a precision saw I made using a portable 9.25’’ (335mm) Triton saw mounted under a hinged flap. The angle of the flap is controlled by a clamped strut and fine adjustment screw. On the other side of the bench is a traveling table that runs on a pair of ‘Quad-Ball’ sliding door tracks made from extruded aluminum. These employ four large steel balls that produce smooth travel and absolute lateral stability. The vertical angle between the saw blade and the table surface is set with the help of a precision protractor and modified bevel gauge. The table has wing nuts for clamping the work and a hinged adjustable straight edge for aligning the cut line. A preliminary cut is made a few millimeters outside the pencil line and this is used to align the straight edge. The work is then moved so the pencil line is precisely under the straight edge and the straight edge is swung out of the way before the final cut is made.
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Private individuals are welcome to build themselves copies of this saw table, but commercial manufacture is subject to intellectual ownership of Ligno3D Systems. This table can make cuts up to one meter long with perfect accuracy. A sliding table could also be made to run along a slot like that used to guide the miter gauge of a standard circular bench saw. Such a sliding table could be easily made from plywood or MDF, using the same clamping and straight-edge mechanisms used in the illustrated table. It should be sufficiently accurate for making L3DD-designed objects.
The best means of joining faces is the biscuit joint, which allows some movement parallel to the edge being joined. The illustration shows a biscuit jointer in action, its working face held flat against the edge being slotted. There is no need to reset the biscuit jointer’s upper face (black with circular hole) for different angles. Its purpose here is to keep constant the distance from the slot being cut to the acute edge of the work.
Dowels can also be used but they must be positioned more carefully than biscuits. It is very difficult to assemble an entire object with dowels unless some of them are kept very short. However, you may be able to assemble the entire object before injecting the glue along the joints with a hypodermic syringe. I have not yet tried this technique myself.
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Copyright © Ligno3D Systems, 2006
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Tools Required