Fabrication of a semi-octet truss using 1 or 1-1/2 inch mild steel angle bar requires use of several jigs: 2d truss jig, square pyramid jig, and spacers for setting flat bar and holding string line to gauge top angle bar when welding. Each truss comprises 16 square pyramids of 4 pcs 10 or 12 mm by 16.85 cm iron rods welded to a linear array of 19.6 cm flat bar straps set in a 1 or 1-1/2 inch ms angle bar frame 20 cm wide by 282.5 cm long.
Welding: Tack weld first throughout to assemble octet truss, then complete full weld once all metal elements are held in contact. Usually a small amount of grinding required to clear sharp edges. Apply hardener coat to seal and spray 3-6 coats of automotive paint. Paint damage possible (e.g. scratches) during transport and assembly; paint touch-up work may be done after assembly.
To assembly a semi-octet truss, you will need: 2d truss jig and square pyramid jig.
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