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RE: Sawmill pillow block bearing2/22
We have a large horizontal bandsaw mill with two 30-inch wheels. This sawmill can handle boards as wide as 28 inches.
The issue we have is with our KML pillow block bearing, which seems to go bad every 6 to 9 months. We pump grease 2 to 3 times a week thru the grease fitting on the bearing. The rubber seals are well sealed in this ball bearing, so as not to allow dust inside.
However, these pillow block bearings do not last us a long time. Is there any other alternative?
I think??? I have KML bearings on my Hud-Son which I recently replaced due to axle breakage. IF I'm not mistaken Hud-son only advised greasing a sealed bearing every month or longer due to most overgrease and blow out the seals then nature destroys.....NOW on the other hand I installed Cook blade guides and they recommend greasing every evening when done, they say the warm bearing let's grease in thoroughly and seals the moisture out as they cool overnight.
I personally would contact cook sawmills and ask their opinion, Tim is a great guy to help even if not their brand.
Pillow block bearings are very tricky to lubricate. They require a layer of lubrication under 1/1000" thick. If you fill some, most or all the space with grease, the small rollers have to push the grease out of the way with every revolution and this creates heat and lubrication failure. Many pillow block bearings can use oil. With the heat, the expansion of the grease pushes on the seals and causes a failure.
When you have failure, can you see the rollers? Are they dark colored from the heat? When the saw is stopped, can you feel heat on the bearing housing?
Also, when the grease cools at night, this creates a vacuum that sucks in contamination...the hotter the bearing, the greater the vacuum, so the more dirt.
I suspect your rpms are low, so you certainly do not need grease, very little each time-one small squirt-, more than every month or two. If you see grease leaking out the seals, you have many times more grease than you need. A properly maintain pillow block bearing will outlast the equipment.
The #1 cause of pillow block failure (50%) is over greasing. Your comments indicate over greasing. The #2 is poor alignment.
I should have added that you need to use the proper lubricant...not all grease is suitable.
I'd agree with Gene. As counter productive as it may sound it seems like you may be over-greasing. Its one of those situations where more isnt necessarily better.
Id be looking hard at your grease choice as well. Perhaps try a synthetic like Permatex SuperLube and grease as Gene sugessted, one pump weekly or monthly.
could the shaft be bent
Worked over 50 years with bearings. A bearing should never have more than 25 to 30 percent of its cavity filled with grease. Looking at your post you are way over lubricating your bearings which causes over heating and premature failure. Mobile grease 222 is a good one for your application and about 3 or 4 squirts every 150 to 175 hours of operation. You can get an hour meter at Northern Tools, eBay, etc. Your engine oil should be changed also every 50 to 100 hours depending on make,size and model.
You may also have a bearing that is not specked for your application. You may need a radial preloaded bearing setup to carry your load . They will carry a radial and axial load at the same time. An example is on the Cook's sawmill site or a internet search. Could you post a couple pic's of your bearing setup?