Shopsmith Forums

I saw this posted on an other forum, reference was to band saw bearings.
I dont know the posters experience or knowledge level.
I cant believe it based on my 40 some years of working with machinery.
Bearings have a shelf life… sitting idle for long periods (even just a year or so), the lubricant and binder will separate, leaving basically a waxy substance instead of grease. They will feel fine, turn smooth and otherwise seem perfectly normal. But once you start using it, the binder will not provide any lubrication and you will have metal on metal contact that will quickly destroy the bearing. But it’s your machine… if you want to chance it, go for it

ERLover wrote:I saw this posted on an other forum, reference was to band saw bearings.
I dont know the posters experience or knowledge level.
I cant believe it based on my 40 some years of working with machinery.
Bearings have a shelf life… sitting idle for long periods (even just a year or so), the lubricant and binder will separate, leaving basically a waxy substance instead of grease. They will feel fine, turn smooth and otherwise seem perfectly normal. But once you start using it, the binder will not provide any lubrication and you will have metal on metal contact that will quickly destroy the bearing. But it’s your machine… if you want to chance it, go for it

That sounds like a pretty general statement. I would guess that it depends on the particular lubricant used in the bearing.

FWIW, some generator bearings on some military aircraft generators that I used to overhaul for the Air Force did have a shelf life.

John,

FWIW, some generator bearings on some military aircraft generators that I used to overhaul for the Air Force did have a shelf life.

That was the military supply contractor way of selling more bearings to the military at an exorbitant price.!!!!!LOL Just like the almost million dollar toilet seats for subs or was it on AWAC planes?
Seriously, why, what was so special, or like he said, lube separation?

ERLover wrote:John,

FWIW, some generator bearings on some military aircraft generators that I used to overhaul for the Air Force did have a shelf life.

That was the military supply contractor way of selling more bearings to the military at an exorbitant price.!!!!!LOL Just like the almost million dollar toilet seats for subs or was it on AWAC planes?
Seriously, why, what was so special, or like he said, lube separation?

OK, if you say so it must be true.

John did you miss the LOL? I was being fallacious.

ERLover wrote:John did you miss the LOL? I was being fallacious.

No, I forgot the smiley.

I can not say it isn't so but I can also say for sure that is it not always the case. Does that help?

Bearings and the lubricate used in them varies so blanket statements make no sense at all. It is also likely that the lubricate can dry out on bearings without seals faster then ones with better seals..... Just as the use of the bearing makes a difference if it were be in "light duty" vs "heavy duty" and if it were running at a couple of 100 rpm rather then 30K rpm. And just how reliable does this thing with the bearings have to be?

I've got a lot of tools that are 10, 20 and 30 or more years old that have never had the bearings replace/re-lubed/or serviced in that time. Some get a lot of use and some set around for years without being run. Not going to set and worry about bearing failure, if it happens then hey time for a shiny new tool.

When I was in Viet Nam back in the early 1970's we got c-rations that were packed for WWII. I guess the expiration date had not arrived yet?????

Ed

[quote="reible"]I can not say it isn't so but I can also say for sure that is it not always the case. Does that help?

Bearings and the lubricate used in them varies so blanket statements make no sense at all. It is also likely that the lubricate can dry out on bearings without seals faster then ones with better seals..... Just as the use of the bearing makes a difference if it were be in "light duty" vs "heavy duty" and if it were running at a couple of 100 rpm rather then 30K rpm. And just how reliable does this thing with the bearings have to be?

I've got a lot of tools that are 10, 20 and 30 or more years old that have never had the bearings replace/re-lubed/or serviced in that time. Some get a lot of use and some set around for years without being run. Not going to set and worry about bearing failure, if it happens then hey time for a shiny new tool.

When I was in Viet Nam back in the early 1970's we got c-rations that were packed for WWII. I guess the expiration date had not arrived yet?????

Ed [quote/]

Right on Ed. What kind of bearing would you want in the generator of a B-52 on a 36 hour mission (10,000RPM) or flying across the pond in an F-22 for 10 hours (22,000rpm)?

Got it guys, had the part long time ago about rpm, heat, weight, ect, just never heard about shelf life if not being used.

I have bought bearing that came in small boxes. The bearing inside was wrapped in a wax paper sort of thing. I have at times had that wax paper covered with oil. These were sealed bearings and were used in slow rpm applications.

I don't know where the oil came from, left over from manufacturing or leaked out of the bearing.

Again very low rpm applications so I didn't see any real failures.

The bearings we used in computer I/O were shrink wrapped and I was told never to use one that wasn't sealed or was in an oily package. Never had any problems all were cleanly packaged. Although I did change a lot of bearings. These were all very small high speed bearings.