Hi all,



I'm in the process of replacing the spindle bearings on my '45 Gorton 8D.
The spindle is set up with a pair of tapered bearings on the top of the
spindle and a pair of tapered bearings on the bottom of the spindle.



I've pulled the old bearings out and have purchased new equivalents; or as
close as I can get. They're class seven FAG units.



Anyhow, the manual for an 8 ½D (which is all I have) suggests a couple of
things that I'm not familiar with. I'm hoping to get some help from the
folks on this NG. The manual suggests that I should mark the relationship
between the spacer that is clamped between the upper and lower bearing pairs
on the spindle. I admit to spacing out when I pulled the thing apart and
didn't mark the spindle. Any idea why Gorton would suggest this? Balance
perhaps? Any idea of how to rectify this situation? The manual also
suggest pairing the "balance marks" on the bearings together. There are
some marks on the bearing races but I'm wondering if this is a requirement
for new bearings or if anyone has even heard of this. I would have expected
bearings to be in balance by their very nature.



My last question is regarding the lubrication of the bearings. I think they
are lubricated by light spindle oil from the oil cups (I need to trace the
oil path to make sure). Assuming that they are lubed by the oil cups,
should they also be packed with grease? My assumption is "no", but I'm
wondering if anyone has specific or even general info on lubrication of
spindles of this type or vintage. If they should be greased, what type of
grease should I use? The information provided by the manufacturer on
allowable bearing loads when packed with grease vs. lubed with oil suggests
that either will work fine given the loads and RPMs the mill will see.



Any suggestions, thoughts, or recommendations are appreciated.



Thanks,



Peter

I admit to spacing out when I pulled the thing apart and
didn't mark the spindle. Any idea why Gorton would suggest this? Balance
perhaps?


The bearings are gound as a set, and "witness marks" are engraved on them.

These marks should be aligned when the spacer is inserted between them.

Same issue on lathe spindles.

"Peter H." wrote in message
...


I admit to spacing out when I pulled the thing apart and
didn't mark the spindle. Any idea why Gorton would suggest this? Balance
perhaps?


The bearings are gound as a set, and "witness marks" are engraved on them.

These marks should be aligned when the spacer is inserted between them.

I'm assuming that the new bearings I bought weren't ground as a set - they
didn't come packaged that way. They do have "dots" etched or marked on the
outer races. Would these be the witness marks?

What's the point of having the spacer align with the witness marks? There
seems to be no difference that I can measure in the length of the spacer at
various points around the shoulder.

Peter

"Peter Grey" wrote in message
ink.net...

"Peter H." wrote in message
...


I admit to spacing out when I pulled the thing apart and
didn't mark the spindle. Any idea why Gorton would suggest this?
Balance
perhaps?


The bearings are gound as a set, and "witness marks" are engraved on
them.

These marks should be aligned when the spacer is inserted between them.

I'm assuming that the new bearings I bought weren't ground as a set - they
didn't come packaged that way. They do have "dots" etched or marked on
the
outer races. Would these be the witness marks?

What's the point of having the spacer align with the witness marks? There
seems to be no difference that I can measure in the length of the spacer
at
various points around the shoulder.

Peter

When you get down to the level of precision of these bearings, millionths
are of concern. It's highly unlikely you'd be able to discern any
differences with common measuring tools, but the end result of the spindle
precision is at stake. If you were working on a jig borer or a precision
grinder it would be very important that you assembled the bearings in proper
order. Most of us that work at home have few, if any, requirements that
would be in keeping with the level of precision involved, and you may not
even be able to detect the differences in the spindle. It is highly
unlikely it would be a concern because the differences are in millionths,
not thousandths. Considering you have no idea how the spacer relates
to the bearings because you didn't mark it, I'm of the opinion that you can
simply assemble and run your bearings with acceptable results. Be certain
you have them assembled in the right direction, for most of them are built
to be run under some preload, so they come apart if assembled in the wrong
direction. Once that happens, they are junk. blush. Don't ask.

Harold