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This blog features the current woodcraft, Art and Graphic work of David Stanley.

Sunday, November 19, 2017

Carving the Gears on the Whimsical Wood Automata

Firstly I had cut the gear wheels and other mechanical devices from 6mm ply, in order to test a 'mock-up' assembly of the automata. Later the final, much thicker gears needed to be cut and shaped for the final assembly of the automata. The highly decorative look that I wanted for the gear wheels meant using thick blanks, 20mm to 25mm in thickness.

There would be a couple of problems that the material used would have to avoid if the gears were to function well. This would be particularly critical because the gear train was to be so long that accumulative errors would literally cause a grinding halt. The first problem was cutting a close enough to vertical line when cutting the gear shapes on the scroll saw and the second was wood movement after the cutting if plywood wasn't used.

Plywood would solve the wood movement problem well enough, but it doesn't carve very well. One solution was to 'veneer' both faces of some existing ply with around the same thickness of suitable timber for carving. Another was to make some relatively thick homemade three-ply from desired timber.

Blanks of gear carving ply were prepared and as coarse a blade as still able to negotiate the cutting line was chosen to cut that vertical cut mentioned before. I found a # 5 modified geometry blade able to do this reasonably well even in oak and jarra."

After cutting the teeth with a careful vertical cut, the inside cuts for the decorative spokes were cut with the table tilted various amounts for effect. Theffect produced with a slanted cut sometimes allows a slender, light look to the spokes on the viewable face but backed up with plenty of substance at the back.

After cutting on the scroll saw the thick 'veneers' of the ply were carved, sanded and finished with the same wipe on polyurethane finishing process that I used on the carved lettering. Some parts were cut from solid timber where wood movement seemed unlikely to be problematic.
In this way the more decorative gears and other parts were cut and carved while other smaller gears were, sometimes decoratively fretted, or cut unadorned from regular plywood. Many of the sculpturally decorative moving parts of this automata are hidden from view, deep within, what is admittedly an overdone redundancy-ridden whole. However one purpose of this project was always to be experiment and consequent learning.