Specification for grease

[hat]

I have a milling machine ( two years old and in fairly regular use)the manufacturers recommendation is to re-grease the bearings every year. Fine, but what is the recommended grease for such a job and is it necessary to clean/ flush out the old grease

[ron]

Hi
Castrol LM is a good multi-purpose bearing grease, if you aren't actually losing any grease out of the bearing housings, once a year seems to be rather frequent, is it a Chinese mill? they seem to be very keen on very frequent lubrication for some reason. To clean or flush out the old grease is a bit OTT as it usually means completely dismantling the assembly which is probably not necessary, a top up would probably do. Also remember overgreasing can cause as many problems as undergreasing.
Ron

[havoc]

If it is a roller bearing, you can get roller bearing grease at any car parts dealer.

[Noddy]

I can't speak for your mill, but with many machines designed to work in dirty environments (I'm thinking farms, construction sites, mines and quarries) the bearings and oil seals are protected by excess grease.

with those machines, you simply pump grease into the appropriate nipple until you are happy that cleanish grease is coming out the other end. this flushes out any foreign materials that have found their way in, together with any moisture and flakes of bearing.

as I say, those machines are designed for such treatment. I don't know about your mill, and do know that a grease gun makes an effective master cylinder for a hydraulic jack (many tracked vehicles use grease pressure from a grease gun to adjust track tension), I would not like to be responsible for "pulling" the bearings of your mill's spindle, or filling the motor with grease!

with some of the fancy greases (CV joint moly sulphide grease) I've found that the oil base oxidises and turns to varnish. Ive never seen that happen with the cheap lithium greases (yet).

sorry that i've probably added to your confusion
Keith

[hat]

Thanks for all the advice - The mill is a Chester Champion - I have had the top pulley off and exposed the races that appeared to be well packed with the original grease - at the bottom end of the quill there is a large flange/ threaded plate and I have had that off and again the races look well packed with grease. For the time being I will leave well alone! I am well pleased with the Mill although it suffers from the circular post setting up problem if you try to lift or lower the head.
However a solution - I bought a builders adjustable laser that was cramped to a 45 degree set square - used for setting the angle of roof trusses etc - I removed the laser and fitted it to the front face of the head- dead square to the post- so if I lift the head it is a simple matter of getting the laser to line up with the front "rule" by traversing the bed and ensure that it measures 0 on the scale - then re-locking the column
A simple solution that works well.