Ball race assembly

Among all the stuff that I have accumulated in my workshop, are a large number of ball races of various types. Some are of the type that I believe are called "fully filled" or "crowded" races; i.e. they do not have cages, and the balls nearly touch. My question is; how on earth are they put together? I have some, where small grooves in the inner and the outer are visible, and if aligned, then the balls could be inserted. However, at least two examples have no detectable grooves. Short of brute force, I can't see how it's done. What is the secret please?

I believe tiny leprechauns with files carve 'em out of the solid?

.

This may not be so poetic ... but

MuchaelG.

Powerful magnets are used to temporarily reduce the ball diameter by 105, not a lot, but just enough. Assembly is carried out under weak green or red light, then the assembled races are exposed to a bright flash of blue/white light. For about three minutes the races 'plink' like metallic popcorn. Around 0.01% of races are rejects because one or more balls don't expand, or distort and these have to be detected These days the process can be fully automated, but in parts of Tibet the process is farmed out as a cottage industry as the tinkling of the races resembles small cymbals or wind chimes and is considered to propriate good fortune. This necessitate thr movement of large quantities of balls in light-sealed containers into remote rural areas, not a big hazard these days when a Toyota Landcruiser or similar is available, but in the 70s and 80s Musk oxen were used along with fabric covered baskets. This meant the balls could only be moved safely at nights with no more thana  new moon showing, a risk process for all the obvious reasons.

Neil

Edited By Neil Wyatt on 27/05/2016 10:46:09

I would think cryogenics would play a part somewhere in the production process. Can achieve a DeltaT of somewhere in the region of 500K without too much difficulty, or risk to the heat treatment of the outer race.

Sounds like a load of balls.

Clive

More plausible than Magic or leprechauns!

Neil

Maurice, you will get a sensible answer from Youtube if you search for 'Ball Bearing'

Nice one Neil

Started reading & then got on to the second sentence... ... Doh!

George.

Thanks for the response gents; Nieil had me believing him for a sentence or two; well done! AndyA, I have tried uTube in the past, and just got video of metal fingers spreading a set of balls prior to a cage being fitted. Do you have a uTube address that shows the assembly of the fully filled sort? While we are on the subject, how are the balls themselves made? I've heard vague tales of grinding them between iron plates, but that sounds a bit haphazard. Regards

Maurice

So Neil was winding us up

As an apprentice I went with others to RHP in Chelmsford and they ground the steel balls between two plates with grooves in with plenty of grinding paste and water. this video shows exactly how they are manufactured https://www.youtube.com/watch?v=CFs4zOC2Yg0

Martin P

This article recently appeared in Design Solutions

http://www.bardenbearings.co.uk/Smaller_faster_hotter_optimisation_of_bearings_for_challenging_applications.html

Part of it mentions full complement bearings and the different types

Bob D