30273Re: [mill_drill] Re: Harbor Freight 33686 Spindle greasing.....
- Jan 1, 2012I think it gets hotter than that in my shop in the summer LOL
----- Original Message -----
From: "Art Eckstein" <art.eckstein@...>
Sent: Sunday, January 01, 2012 8:04 AM
Subject: Re: [mill_drill] Re: Harbor Freight 33686 Spindle greasing.....
Here is the break-in advise that I found and followed:
Typical run in for spindles is a starting point of about 400 rpm,
up to max in 500 rpm increments, in steps of 30 - 45 minutes.
Check housings for excessive heat as you go.
Then reverse and do it over!
Watch temperature. If it gets hot, stop let cool and do over.
The Fafnir Superprecision Machine Tool Bearing catalog suggests that
with optimal design,
bearings running synthetic low friction grease ought to be able to
run about 20 degrees C
over ambient or about 40 degrees F. In fact, they suggest a proper
break-in procedure temperature of 130 degrees F.
involves running the spindle until it reaches 150 degrees F, turning
it off to cool, and repeating the cycle
until the spindle stabilizes at 130 degrees F or lower operating temp.
The ideal equilibrium operating temperature is 95 to 115 degrees F.
Maximum temperatures should not exceed
170 degrees F. Timken's published specs for tapered roller bearings,
including bearing life specs, assume an operating
temperature of 130 degrees F.
As for pre-load, I am afraid it is more a matter of feel and
luck. In an effort to help this, I did my initial break-in on the
lathe. That way, if I felt it was to tight or to loose, it was real
easy to adjust.
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