I note that you call out 14 perimeters for the second hand; what do you recommend using for the minute and hour hands? thanks
Steve I downloaded the file for the SP10 clock it calls for gearmotor 9 I don't see it. Love the clocks. thanks Norm
14 perimeters are specified for the second hand to make the tail completely solid. 100% infill would have the same result without looking as good. The solid tail is needed to keep the second hand balanced so the clock will run quietly. A hollow tail would be unbalanced and would pull the second hand gear away from the motor pinion at 3 o'clock and would drag against the motor pinion a 9 o'clock. These inconsistencies would allow the gears to rattle. A balanced second hand provides a more uniform load to the motor pinion with less noise.
This long-winded explanation was added to explain why 14 perimeters is specified for the second hand. An unbalanced minute hand would have 1/60th as much impact on gear noise as an unbalanced second hand. The hour hand would have even less impact. This is so insignificant that it doesn't matter for noise. Use anything you like for the hour hand and minute hand.