Bellevilles – Metric Discs.
Gardner Metric Disc Springs are manufactured to strict DIN 2093 standards. Parts with thickness below 1.25 mm have no machining. Parts with thicknesses from 1.25 mm – 6 mm have OD and ID machined. Parts with thicknesses of 6 mm and above are machined all over. Parts through GMB-145 are made from C75S. GMB-150 and above are made from 51CrV4.