Diamond Drills
Pieces or copper wire, in the ends of which are embedded fragments of diamond in the shape of triangular prisms and held in place with shellac. They are used for drilling jewels, etc. They may be obtained from material dealers.
How to true a balance, repair a chipped dial, temper a spring or test a stone — the working bench-book of the American watch trade, arranged A to Z.
Pieces or copper wire, in the ends of which are embedded fragments of diamond in the shape of triangular prisms and held in place with shellac. They are used for drilling jewels, etc. They may be obtained from material dealers.