ISO 641:1975

Laboratory glassware — Interchangeable spherical ground joints

The requirements deal with the geometric charateristics to ensure interchangeability. The dimensions of the joint-ground zone and the outer diameter of the tube connected to the joint are given in a table and illustrated in a drawing. In addition the surface finish is specified. A system of gauges (stell balls) for testing the ball cup is tabled. In the annex a method of testing the leakage including the apparatus is described.