Birmingham Seals is a distributor who is capable of supplying your requirements for loose balls in nearly every variation of grades available.

We can supply an extensive range of product sizes from 0.2mm diameter up to 150mm diameter.

Product can be packed in customer specific quantities and to specific packaging requirements. We are able to handle large one off bulk deliveries as well as call off/scheduled orders.

To order product please see below a grading system based on ISO and ABMA standards.

Typical applications for these grades are as follows,

Grade Application

G5, G10High precision bearings, Gauges

G25Precision bearings

G100 Bearings, drawer

G200 Soap dispensers, Body jewellery

G500 Automotive seat slides, Bicycles

G1000 Castors, Unground bearings

G2000 Agitators, Decorative uses, Weights, Ballast

Useful Terms and Definitions used to describe Precision Balls.

  1. Nominal Ball Diameter – The diameter value that is used for the general identification of a ball size.
  2. Single Ball Diameter – The distance between two parrallel planes tangential to the actual ball surface.
  3. Diameter Tolerance per Batch – The allowed difference between the smallest measured ball diameter and the largest ball diameter within the same batch or lot.
  4. Batch or Lot – A definite quantity of balls manufactured under conditions presumed to be uniform and which is considered an entity.
  5. Sphericity – A measure of roundness expressed as the difference between the measured roundness of a ball and a perfectly round ball.
  6. Surface Finish or Roughness – A measure of the texture of a surface. It is quantified by the vertical deviations of the actual surface from it’s ideal form, if these deviations are large the surface is rough; if they are small the surface is smooth.
  7. Hardness – A measure of resistance to penetration as determined by specific methods, usually Rockwell or Vickers Hardness.