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Building A Ball Bearing - Part 2

Part one took a look into the first stages of building a ball bearing, part two looks into the final stages of the manufacturing process and how the quality of the final product is checked.

The Grind Goes On...

Every part of the race is finished by the grinding process, leaving a smooth surface which is required. Once the races are shaped perfectly, a fine abrasive formula is used to polish the races. This may take several hours depending on the size and produces a mirror like finish. Once they are finished, they are ready to be put together with the balls.

Making The Balls

The balls start out as thick wire and are more difficult to create than you would imagine. Wire is fed into the appropriate machine and this will cut it into short pieces which are then crushed into the middle.

As with the races, the balls now look like Saturn again, with a ring around the centre of the ball which is then machine removed. This is done by putting the ball in between two discs, with one rotating and the other staying still, the friction will remove the ring. There are several minor processes which then take place to leave the balls with the very smooth finish which is demanded by all top quality bearing manufacturers. The balls will be left slight over sized so they can be ground by a small amount when going through the finishing process.

Heat Treating

The ball heat treating process is similar to that of the one for the races, this is so all the parts wear down at around the same rate. The balls are now extremely tough after their heat treatment and are put into a machine which is similar to the one which removed the Saturn like ring in the first place, the only difference being that they are ground ever so slightly to be as close to their finishing size before the abrasive treatment.

The balls are then put into the same machine which will use an abrasive chemical to make the finished product as smooth as possible like with the races. Depending on the size, the balls will be in this machine for around 8 hours or more depending on the required precision of the finished product.

In Part 3...

Part three will take a greater look into the process of creating the cage of the ball bearing and the process of assembling the two races, the cage and the ball into one fully functional unit. The quality control process will also be looked at due to the precise nature of the business!

Other topics in the ACORN Bearing Compendium series include: 

Building a ball bearing - Part 1

Building a ball bearing - Part 3

How are bearings made

Bearing terminology