Clock spring balance

A sensitive balance for use among 0-1 g or 1-10 g is readily made using a piece of clock spring and a block of wood or cotton reel.

 Fasten the wooden block or cotton reel down to a convenient base. Fix a piece of watch spring about U) cm long to it and make a cardboard or paper conical pan. Fix the pan to the spring near the free end using sealing wax or cements suggested in Chapter XVIII. Use the free end as a pointer, and a postcard as a scale, and calibrate it by putting weights in the pan. The sensitivity depends on the spring used, but the scale is a reasonably open one.