Drilled Ball (SET) These drilled balls are excellent for use as pendulum bobs or in impact and collision experiments. All drilled balls feature 3 mm countersunk holes so pendulum cord knots can be recessed. SKU: PMS001 Product Description Material: – Aluminium, Wood, Brass, Steel, Iron, Copper, Lead. Sizes: – 19 mm, 25 mm, 38 mm diameter (all sizes available). Related Items: Steam Engine Model With Boiler Steam Engine Model Bearing Balls Pulley On Rod << return to products