No 20 machine oil

In the manual for the mill i have just bought it specifies "No 20 machine oil" Could this be SAE 20W? would that be a suitable oil for a mill gearbox?

Adrian

I think the answer will depend on the country where the instructions were written, Adrian. Rather like hat and shoe sizes, I'm afraid - so offer a bit more detail and someone (from that country, ideally) might be able to help.

Cheers, Tim

It is Chinese, the original manufacturer/model is ZX-16 It was sold by Engineers Tool Room as the BMD-16

SAE 20W is unlikely to be suitable, it's the right viscosity only at Winter temperatures

No 20 seems to be ISO68, with US sites recommending Mobil DTE Heavy/Medium

Part of the fun owning an older machine is working out what the modern equivalent of long obsolete oils is! Usually one of the oils recommended for a similar machine will be suitable. However, when looking at alternatives bear in mind common modern oils are often engineered with additives and synthetics to suit today's requirements. These 'go faster' oils can have negative effects on older equipment, such as additives that attack copper in bearings, or low cold viscosities that only thicken up properly in a hot engine. Check the specification.

Edit: It's a Chinese Mill!  Much less fussy.  I use Hydraulic Oil.

Dave

Edited By SillyOldDuffer on 08/04/2019 18:11:57

Yes, SAE 20 is often specced for machinery gearboxes, it's quite thin so best for gears that run in a bath.

Neil

Well... that's three completely different answers to choose from...

Neil

Excellent ISO 68 SAE 20 is the same oil as the lathe needs.

I was thinking of Lodexol if I can find it in a smaller quantity or Liquimatic

Anyone know another?

And this is the lathe.

The mill is in the vehicle pulling the trailer.

Martin C

I had been looking at Alex Oils for SAE 20/ISO 68 and noticed that there are two alternatives, Lumach 68 Lubricating Oil and Lubron ISO 68 Hydraulic Oil. Given that they are both the same price, would there be any advantage to the hydraulic oil?

Brian

I use a straight ISO68 hydraulic oil for my lathe headstock gears and the spindle, and powerfeed, gearboxes on the my horizontal mill. No need to EP oils, neither machine is particularly powerful, less than 5hp. I use an ISO68 slideway oil for general machine lubrication. A slideway oil has additives that make the oil slightly sticky, so it stays on the slideways.

Andrew

I have been reading about the effects of sulphur used in the EP additives on yellow metal bearings. Are hydraulic oils free from sulphur and compatible with yellow metal bearings?

Adrian

Hydraulic oils have many additives, usually also anti-wear additives (like zinc dialkyldithiophosphate), see here, or here. Sulphur based EP additives may attack yellow metal bearings. But I have never experienced any problem with hydraulic oil and yellow metal bearings.

Thor

Hmm, just been reading about zinc (ZDDP), it too can corrode yellow metals.

I did contact Warco about their headstock oil. They say it is suitable for the BH900 but wont tell me the ISO or SAE, so I am not too keen to put it in the mill. Plus it is quite expensive.

So these two, including delivery only £4 difference in cost; Lubron zinc free or Morris liquimatic which also comes in a nice old fashioned tin. I think the tin wins, order placed.

It's dangerous to generalise. These days most oils contain additives of some sort. Usually a good thing, but sometimes incompatible with a particular machine. EP ( 'Extreme Pressure' ) oils often, but not always, contain a sulphur based additive that attacks copper alloys. The same additive may be in oils other than EP types.

In case of doubt, read the data sheet. This Morris example includes the phrase, 'Compatible with all bronze, silver and steel system parts'.

My rules of thumb in the workshop for lubricating in the absence of proper instructions:

1. Never use grease when oil is specified or vice versa
2. Any oil is better than no oil.
3. Avoid modern motor oils; these are designed for service in a hot car engine and are highly engineered for that purpose. (Old-fashioned straight motor oils are more general purpose but are getting hard to find.)
4. Getting the viscosity about right is often 'good enough'
5. Hydraulic oils are generally useful for everything. (EP types are usually unnecessary unless the specification calls for it.)

Dave

Edited By SillyOldDuffer on 13/04/2019 10:17:27

Hi Dave,

The Morris oil in your example is the one I just ordered. So all good.

Adrian

+1 for Morris lubricants. They even make steam oils.

Here's an example of a substitution I have found works very well... using sewing machine oil instead of 'lemon oil' for guitar fingerboards. 'Lemon oil'* for this purpose is just highly refined thin mineral oil with a scent added, sewing machine oil is just highly refined thin mineral oil.

Neil

*Not to be confused with pure lemon oil which is irritant to the skin.

Does the ZX-16 (BMD-16) have an oil-fillled gearbox? It appears to be a bench top mill similar to others which have grease lubricated gears, like my Warco WM-16.

Cheers,
Ed.

Ed,

Yeup, defiantly was oil filled. After removing the motor, I lay the head down and forgot about the oil. I now have a nice puddle on the new workshop floor.

FYI this is it.

Adrian.

Edited By AdrianR on 13/04/2019 19:58:46

Hydraulic oil is just water that doesn't rust things. The clue is in the name. It is expected to be pumped around cold things so is thin and 'cos it is oil based it sort of lubricates.
Oil for car engines is thicker because it is doesn't get pumped around much and needs to do some serious lubricating of those slidey things called pistons. This also works for the gears in the car gearbox. But it has al sorts of additives to cope with the heat and yucky stuff that the suck squeeze bang out process contaminates it with. They are thicker when cold but at their normally hot operating condition are a lot thinner.
A midway point is automatic gearboxes. They have gears that want lubricating, don't get too hot so need to be thinner to start with, no yucky byproducts to deal with, and have pumps that run the actuators so that also needs them to be thinner.

Which of the above sounds closest to your application?