Stroboscope Hand

Comprising two plastic tubes one 305 x 32 mm diameter, the other 305 x 25 mm diameter. The small tube slides within the other in foam plastic collars, allowing the air column length to be varied from 300 to 530 mm.

With four toothed wheels each 75 mm dia, fixed 6 mm apart on a shaft, projecting as spindle with slight taper at its end. Wheels have 36, 45, 54, and 72 teeth respectively, used with whirling table