Hardened precision steel balls in quality G10 according to DIN 5401. Data: Ø 6.350 mm, M20 (actual dimension 6.330 mm) - material 1.3505. weight per piece: approx.1.033g, AISI 52100.l 100 Cr6. hardness between 60 and 66 HRC. Balls made of this material have an excellent surface finish, excellent hardness and high load-bearing capacity. They are also dimensionally stable and extremely wear-resistant. The balls are non-magnetic, but can be attracted by magnets. G10 quality balls are very rare.
Steel balls in size 1/4" fit many classic cup & cone btoorm brackets and rear wheel hubs.