Spindle bearings again - that old chestnut....

[Davek0974]

Have been reading all afternoon and only managed to muddy the waters more.

I have a spindle that needs bearings, its a QC30 and i want to fit in my BR2J head.

Does anyone know of suitable bering codes - i have read stories that quote super-special-££££ items and then this that fitted off-the shelf items and all are happy, seems a good angular contact pair is needed but what code do i search for??

Any help appreciated.

[johnsattuk]

What is the OD of the bearing, do they have a code engraved on them. Using std. bearings can work OK if you can get the preload stup properly, one of the properties of the super bearings is that they are usually sold as matched pairs which when assembled have the correct preload. They are also matched for eccentricity and have alignment markings for correct assembley

[Davek0974]

As far as i can tell, 35ID, 72OD, 17W

From what i have read, the new parts do not come with any markings now.

[johnsattuk]

I have several sets of super precision bearings but mine are a lighter section 30/35/40 ID 62OD 12W and are meant for high speed spindles. No marking is perhaps a sign that manufacturing tolerances have become good enough to meet the specs. All mine are matched pairs with markings.

[Colin Barron]

Dave,
Looking at the drawing of the j head i would find someone who repairs these spindles for advice. You need the full bearing number for the angular contact matched pair. If you get the number they will be much cheaper from one of the bearing suppliers. Also what grease is required and what preload?

[Davek0974]

Trouble with rebuilders is that they quote the really expensive item as their reputation is on the line.

In the end i cleaned and refitted the original bearings, they were genuine and marked with custom grind codes for the pre-load as well as alignment marks. Pre-load is set in the bearings as the spacer collars are identical in length, i think if you fit un-ground bearings you need to get the spacers ground for pre-load.

No grease - this head is oil lubricated, total-loss system.