Attention! Rancid grease in semi-universal dividing head BS-0, BS-1, universal dividing head BS-2.

Hi all people who own Chinese made semi-universal dividing head BS-0, BS-1, universal dividing head BS-2.

When I used the dividing head, I discovered that there were hard points in the bearing, the crank did not feel the same all the way. Then I noticed that the workpiece that was milled was not in the center since I use an adapter with ER-32 collet attached in dividing head.

So I measured with the dial on the cone inside the dividing head and discovered that it was a throw. Tried to adjust the thrust bearing without it helping, still slack in the spindle.

So I disassembled the dividing head and discovered the grease was rancid and hard mass.
Washed all parts clean and free of rancid grease. These bearings was checked and found to not be damaged. Note: Replace bearings if damaged or hard points in bearings. Greased with new wheel bearing grease that I have lying in my workshop room. So I adjusted the thrust bearing, but still slack. Found that the length of the shaft was a bit too long. So I put a 3 mm / 1/8" thick disc that I have turned to adjust between the adjusting nut and the thrust bearing. Then there was no slack and reduced throw in the spindle.

In other words, the Chinese grease that was used to lubricate the bearings and gears in the dividing head was of poor quality that turns rancid and hardens over time.

Encourages you to clean and lubricate with bearing grease in the chinese dividing head so the quality of dividing head will be better.

Regards Jens Eirik

Edited By Jens Eirik Skogstad on 03/05/2021 20:53:45

There are even more chinese restaurants and takaways there, so the old fat has to go somewhere.

Thank you very much for that advice.

I have a similar dividing-head that I acquired looking as if unused (from a bereavement sale), and I too have noticed one or two strange hard spots in the rotation. And that was simply turning the main spindle by hand, without the worm.

Same I had the hard points in the bearings due hard grease inside when I released from worm gear.

Thanks for the ‘heads-up’ but it is not restricted to just that dividing head. Many cheap items, that come out of china, are likewise blessed with ‘wok-pan fat’ as lubricant. If they use that low quality for lubrication I would expect the bearings were never of particularly good quality, either.

Is 'rancid' the right word?

I don't think so Neil but I give Jens the benefit of doubt, when I saw the thread title I thought it was a bacterial problem, butter goes rancid if not kept in the right conditions and stinks so perhaps Jens was likening the grease to that smell.

Emgee

I had the similar issues with a X axis power feed i fitted to the Tom Senior. It struggled to operate. When stripped it was full of pretty well set, dark brown gunge. Oh & yes it was rancid. My hands stank for days.

Steve.

It's not just Chinese grease that can go hard, depends on the makeup but if it was 'thinnned' from a hard type to make it go further or meet a light grease spec then the solvent evaporates and it goes back to being thick, unlike a specially formulated grease. It can affect a lathe that has been in store or not used for a few years after the previous owner couldn't get down to the shed anymore.

BTW not sure if I mentioned it on another thread on the BS0 but the key on the worm wheel is deliberately deformed to make sure it is a zero backlash fit so don't go improving the finish.

Neil Wyatt,.. I do not have the right words to express, grease had become useless and hard that grease no longer lubricates moving parts.

Regards Jens Eirik

That's what I understood from your description, I think generally it's 'dried up' so the water has been lost from the emulsion, leaving the oily constituents as a hard wax.

Rancid suggests stinky bacterial/fungal spoilage (like with suds).

Neil

Neil,.. in our Norwegian language, we say that the fat has turned rancid when the fat has become hard and useless. Understandable that Norwegians and Englishmen have their opinions on the word "to turn rancid".

Regards Jens Eirik