guide roller bearings

[sawwood]

We have a Norwood Mark 4 mill and i will take the bolt that the guide mounts on to have it drilled
for a grease fitting. Is there a different type of bearing for greasing compared to sealed ones ?
I need to replace the bearings in our guide and want to get the right ones.

Sawwood 

[Crusarius]

I would stick with non greasable. How long did the old ones last?

[sawwood]

I changed the first ones about a year ago. I don't know if the ones I used where the best. Now the ones
on the drive side are bad and the other one are starting to sound rough. I know Cook's use grease bearings
and wanted to do the same to our mill. I know of a machine shop that will drill our bolt for a grease fitting.

Sawwood

[Magicman]

You could drill a bolt for a grease fitting thereby creating a "wet bolt" but how then will the grease get out of the bolt and inside of the bearing?  If you do go to a grease-able situation be sure to not use a "multi-purpose" grease.  Use a high temp-high pressure grease.

I regularly wear out the guide rollers before the sealed bearing go bad, and that takes about 3 years.  My thoughts are that you may need another bearing supplier.

I installed wet bolts and bronze sleeves on my camper's suspension but that is far from a sawmill's blade guides.   

[sawwood]

Magicman when i have the bolt drilled for the grease fitting and then a cross hole between the two
bearings, not sure if the grease will push up in to the bearing as the center and outer ring mate together.
That is why i was asking if there was a different types of bearings.

Sawwood

[Gearbox]

Be very careful greasing high speed bearings . Grease is oil with a carrier when you fill a bearing with grease the rollers will plow and slip until the grease is expelled and only a thin film of oil and carrier is left . If the plowing and slipping flattens the rollers so goes your bearing life . If it was  me I would stay with sealed and when replaced idle the machine for 10 or 15 be for putting it to work . A loaded bearing only runs a 10 micron oil film .

[Pabene]

I have two bearings in each roller. I have drilled the bolts and changed the bearings to "one side sealed". That way I cold drill a hole in to the center hole  of the bolt, between the bearings. If you have low temperature during the winter it is better to use an oilpress. Oil is the best for the bearings. I have used oil sins 8 years ago and the bearings are still in good shape. In the end of the day, I give the rollers two "pump stroke" oil from the oilpress. (When the rollers heats up the air inside will expand and some air and oil are pressed out. When the rollers get cooler air will be sucked in again. If there is water present outside the bearings, it will follow the air in and it is not good for the bearings. To oil the bearings at the end of the day will help.)

[Coltbodi]

I have greasable bearings on my mill. I put on the cooks retrofit with there rollerguides to replace the simple bearings on my mill. I couldn't tell you if the sealed bearings last longer or not since I've never used them. But If you do decide to go with greasable bearings you can probably buy a zirk bolt (bolt with a zirk fitting for greasing bearings) for cheaper than you can get one machined. Not sure how your mill is set up with what bolt you need. I know the ones from cooks are only about $12.00 a piece. But to answer your question about the bearing, they are different. On a greasable bearing only one side has a seal ring on it, the other side is open, so you can actually see the ball bearings on the inside. On the rim of the side with the opening will be a notch or two. So when you put two greasable bearings together with the open sides facing each other the grease can come out of the thru hole in the zirk bolt and go thru the notchs in the rim to get in to the ball bearings. To add to which type of bearing last longer also depends on the lube system. If you run a water system like what is on the timberking mills it send a constant slurry of water all over your bearings which can potentially cause an early fail of a sealed bearing since there is no way to keep the grease packed in which is where a greasable bearing really comes in handy. But if you have a felt wiper system that only applies a small amount of lube to the blade then the entire process is much cleaner and will dramatically increase the life of the bearings. But these are just my thoughts on the matter. I hope whatever you go with works out for the best for you.

notice the two notches on the inner ring

[TKehl]

By the time you add the machine cost and new bearings, a Cook's retrofit kit would be worth looking at.