letter/spring scale for small weights

thingiverse

letter/spring scale for small weights accuracy from 2 grams wanted on my desk a small scale to weigh e.g. letters. needed are: 7 cm steel/welding wire Ø 0.8mm or a straight bent paper clip. 2x M3 x 6mm countersunk screw 1x M3 x 12mm cylinder head/ lens head screw 1x M3 nut 1x tension spring Ø7.6mm - length 30mm - wireØ 0.5mm please note: the spring must not have too much pre-tension, otherwise the pointer will react too late. therefore, stretch the spring a little beforehand by pulling it carefully so that the coils lie against each other but without pre-tension. assemble the scale as shown in the pictures. first put the spring on the pointer (part 3) and the holder (part 6). then put the moving parts together (parts 1 to 4). make the wire pieces 16mm long - insert and close the holes with glue or soldering iron. important: the 4 moving parts must move easily. then screw the fixed part (part 1) to the base (part 5) with the 2 screws (6mm). screw the screw (approx. 12mm) to the base with the nut and connect the holder (part 6) to the screw. the spring must not be twisted in itself. then lock the screw with the nut. place the plate (part 7) on the bolt (part 2). do not glue, so that you can adjust the tension of the spring later. then provide different weights. put the weights on the plate and make a line with a pencil. depending - e.g. at 0, 5, 10, 20 grams. measure the distances and print a small paper strip (12 x 50mm) with the lines and numbers. fix the strip with a piece of adhesive tape. https://youtu.be/FktWFe1nqDk