Hello Steve,

I use lithium based grease from Castrol, but just about all the manufacturers will have a lithium grease in their range. Try Halfords as a start, but you can get it from motor factors, usually much cheaper too!

The first time I tried lubricating the bearings I rather overdid it and got grease all over the inside of the cover! Not good for the belt, that is for sure. I now open the cover and grease until I can see signs of movement around the rear roller. As to how often ………. well depends how much you use it. I would guess a good greasing would last about a 100 hours running. So it doesn't have to be done often. Although I am open to correction on this.

Andrew.

Hi Sam,

You are correct, too much grease will make the bearings hot. It has been discussed on this forum, here's a link to what SKF says.

Thor

Lithium or moly (or teflon) grease will be fine. Oil is OK … if you have an oiler to keep them lubricated!

I've been told it's best to fill about 25% of the space in the bearing to avoid overheating and 'ploughing'.

Neil

There is a specific time period for greasing the ML10 bearings, something like 10 hours running and then one pump of the grease gun.

I do not recommend pumping until grease appears, as you found it will come out in quantities and clart everything up.

I could check but I have no wish to go outside at the moment as the temperature is minus 2.5 C.

Clive

I may stand to be corrected here & you my be perfectly right, but grease does not go "Thin" when hot. So I would suggest that if grease is being expelled it is initially due to too much in the bearing. This is what is making the bearing hot which cannot be good for the bearing if over expansion occurs. Agreed some bearings may be designed to run at a certain high temperature.

Re " runny" grease I wanted some " thin " grease so I put some high speed machine grease from one of my moulding machines ( forget the grade) on a tin lid & held it over a blow lamp. Nothing changed as far as the grease was concerned. It certainly did not thin out. This is not conclusive of course but does suggest that general machine grease would stay at a consistent consistency

I have found from experience that Lithium grease does lose a lot of viscosity when hot. I am not certain about other types of grease. However lithium based grease can do this. I have even opened cans that have got very warm in summer and found a liquid on the surface. I am not sure it is supposed to do this, but several different cans have shown this effect over the years!

Maybe an experienced lubrication engineer can comment on this?

Andrew.

Edited By Andrew Tinsley on 27/01/2017 14:28:00

Hello Hopper,

I don't mind in the least at being pulled up for duff information. The problem I have got, is that a lot of the advice appears to be somewhat conflicting. As I said before, there is no way I know of, to determine how much grease there is in an ML10 bearing, So whatever you put in, is pure guesswork. You go on to say, quite rightly, that there are thousands of cars that run for many years with a sealed bearing in the alternator. Is the implication that it is fine to do the same for the ML10 bearing? As to frequency of greasing, if I adhered to the one shot every 10 hours, from my Wanner, then I would rapidly fill up the bearing, which is precisely what you counsel against. I do bow to better knowledge and will not in future fill up the bearings until grease comes out, I am guilty of bad practice.

I am still very curious as to the behaviour of lithium grease. There is no doubt that under very hot summer conditions, in a shed, the grease appears to start melting and there is liquid in the can. I assumed wrongly, that if I overfilled the bearing, then it would self correct, by melting out. I have seen this "melting" behaviour with various makes of lithium grease, but never with any other type. Maybe what I am seeing is not due to a melting process. Does anyone know what is going on here and has anyone else ever seen this curious behaviour?

Thanks,

Andrew.

Just to confound you all, I will quote from the hand book of the ML10 and this also applies to the Speed 10.

Headstock bearings front and rear taper rollor brg, Lubricate every 4 to 6 months with Lithium grease until it oozes out of the bearing.. This on page 6 of the hand book.

Clive

Thank you David!

That seems to explain what I have seen with lithium grease. Thank goodness there is a rational explanation for the phenomena!

Clive,

That will put the cat amongst the pigeons! So the manufacturers seem to care not how much the lathe is used in a 6 month period! Also they don't seem to mind if the grease oozes out.

Maybe the answer is that it doesn't really matter what you do as long as you occasionally remember to grease the little perishers. But stop when you see movement, otherwise you get a very greasy belt! Come to think, maybe I should read the manufacturers handbook, no excuse here as I do have it!

As to the front bearing, God only knows how you see grease oozing out of that one, as it is completely shrouded from prying eyes!

Thanks all for an interesting discussion, at least I now know why you get the liquid formation in the lithium grease.

Thanks again,

Andrew.

LOL, when all else fails, read the destructions.

Thinking about it further, it would seem there must be no proper seals on the ML10 bearings if grease can ooze out. (I'm not familiar with the ML10). So a) filling the bearings full of grease will not result in damaging pressure building up inside, the grease being free to ooze out in  best British engineering tradition. And  b) pumping grease in will flush out swarf and dirt that has gotten into the bearings due to the el cheapo lack of seals on the bearings. Just like on the Myford rubbish felt bed wiper system made up for by flushing out with the oil gun.

But in this day and age, wouldn't synthetic grease work better than lithium?

Edited By Hopper on 29/01/2017 02:00:59

No one seems to have taken the point that you cannot see what the greasing level is in the ML10 bearings. So it makes sense to let the grease come out, at least you know the amount you have got in there!

As to good old British tradition of letting grease out to purge the lubricant in the bearings. Sounds a damn good idea to me. My friends big Chinese lathe has far worse system than that!

Andrew.