Vinyl Asylum: RE: problem with applied fidelity bearing by InDaGroove Welcome Licorice Pizza (LP) lovers! Setup guides and Vinyl FAQ.

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Posted by InDaGroove (M ) on December 11, 2017 at 17:34:14

In Reply to: problem with applied fidelity bearing posted by Patster on November 21, 2017 at 13:20:38:

To all involved with this, and other bearings built by Jim... First off, I am not writing this to disrespect Jim. He was a good friend, had great knowledge, and went overboard to help everyone he dealt with.

Patster sent me his bearing to repair. I found the spindle to be bent, and straightened it to acceptable condition. In the course of working on this bearing, I found that the upper bushing was made of some kind of hard, black plastic material, and the lower bushing was a stock Oilite bushing (oil impregnated bronze). The spindle, apparently nitride coated, showed signs of discoloration in the lower half, which resembled corrosion or contamination. The oil, which was SAE 75-140 gear oil (thick) was a dark yellow color with (possibly) metallic particles, possibly from the bronze bushing.

The clearance between bushing I.D. and spindle O.D. was quite large, around .003" as I recall. I felt it would be best to replace the bushings, as things didn't look quite right.

I removed the original bushings, and immediately saw that the bore in the upper part of the bearing was significantly off center to the lower portion. The result of holding the piece in an off-center lathe chuck, boring one end, then turning the piece around and boring the other end. There was glue, or locktite used on one bushing, indicating that the bearing was bored too large for a suitable press fit, so the bushing had to be glued in. This could have contributed to the contamination of the oil.

The bearing had a threaded plug on the bottom which contained the thrust pad. It was a very course thread. The thread on the plug was turned on a lathe and was undersize. The internal thread in the bearing was tapped, and not straight with the bore, like the tap was angled. The bore for that thread was way oversize, the resulting thread was more like a scratch than a thread, and the solution to keep the oil from leaking out was many wraps of teflon tape.

OK, I've said enough. I'm a good machinist with over 30 years experience. This is definitely not a product that I would pass on to a customer. Again,not trying to throw our good friend Jim's deceased body under the bus, just want to give a head's up that the quality of the machining is suspect.

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