Saturday, July 15, 2017

Making some Z's

A two-ply Z made from white and orange Hatchbox ABS.
My current technique for making 3x2 Z's uses just a single anneal, which might be practical to achieve with a hot air gun. 2.44 m lengths (measured between clamps) of white and orange 1.75 mm ABS 3D printing filament from Hatchbox were stretched using as weights two drill press vises (7 lbs. each) dragged along a carpet.
A slow-speed drill was used to twist the pair of filaments counterclockwise. I believe the total number of turns were about 440 (there were some mishaps in the twisting,) or about 180 turns per m of original length.

Three such 2-ply strands were made. The twist was preserved in each strand with a heavy clamp at the drill's end.

Then the three strands were twisted together in the clockwise direction to a pitch of 0.47 turns per cm on the finished rope. My hope was attaining a 4:1 ratio of strand turns to rope turns to keep a neat phase relationship between the two colors. The actual ratio proved to be 3.8:1, which is not nearly accurate enough to maintain proper color phasing along the length of a Z. Oh well, this is just an appearance issue, they twine together fine. The rope was annealed while stretched in place using a hot air gun. This annealing was not as thorough as might be wished as indicated by the slightly pale orange in the pigmented filament.

The 3x2 annealed rope was then unlaid into its three separate strands in preparation for bending and cutting the Z's.


An all-but-finished tetrahedron woven from the Z's.

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