Thread: Oil for headstocks ?

I use hydraulic oil in my gear head lathe.
ISO 68 is approximately equivalent to SAE 30 in viscosity.
A lot of hydraulic pumps are just two gears meshed together so that is what reassured me to use it on the lathe gears.
Dave

Originally Posted by racer123

I use hydraulic oil in my gear head lathe.
ISO 68 is approximately equivalent to SAE 30 in viscosity.
A lot of hydraulic pumps are just two gears meshed together so that is what reassured me to use it on the lathe gears.
Dave

I beg to differ, according to my equivalent Viscosity Chart, ISO 68 is equivalent to SAE 20W. The equivalent to SAE 30 is ISO 100. Google is your friend.
http://www.engineeringtoolbox.com/iso-vg-grade-d_1206.html

Chas.

Interesting.
The viscosity for ISO 68 on the chart I found matches up between 20SAE and 30SAE at 40 degrees celcius.
But SAE specs are measured at 100 degrees celcius.
The viscocity of the castrol AWH 68 is use is 11.1 at 100 deg C.
Meaning it acts like a ISO 100 oil or an SAE 30.
I think in practice for what we are doing with home use lathes then any oil is a lot better than none.
Attached chart.
Viscosity Information
Regards
David

Originally Posted by racer123

Interesting.
The viscosity for ISO 68 on the chart I found matches up between 20SAE and 30SAE at 40 degrees celcius.
But SAE specs are measured at 100 degrees celcius.
The viscocity of the castrol AWH 68 is use is 11.1 at 100 deg C.
Meaning it acts like a ISO 100 oil or an SAE 30.
I think in practice for what we are doing with home use lathes then any oil is a lot better than none.
Attached chart.
Viscosity Information
Regards
David

Hello David,

You have just discovered that "oils ain't oils". In the case of Hyspin AWH 68 which has its' viscosity index (VI) extended by the inclusion of VI modifing chemicals; if it were classified under SAE specifications it would be a 20W - 30 multigrade oil. Without the VI improver, you would expect the viscosity of this oil to be around 8.5 cSt @ 100C. The single grade SAE classifications as shown in the chart are based on straight mineral oil sampling.

As your application does not involve combustion temperatures, you should base any comparisons solely between the ISO and the SAE 40 degree C viscosity numbers.

Regards,

Chas.

I would not worry too much over what oil to put in it....

I would use DTE heavy medium, but only because the mobil distributor is easy to get to and has it in stock...

An ISO 68 seems to be a common sort of 'weight' of oil to use. My understanding is not to use multigrade oils or oils with detergents added (for example engine oils).
That seems to leave either hydraulic oils or oils like the Tonna 68 that I use - sold as a slide way oil the fine print says that it is also suitable for machine tool gear boxes & bearings.
From a lubrication point of view the machines we run are not that sophisticated - not terribly high speed, manually changed gears (which are straight cut and have reasonable clearance), rolling element bearings that although precision units have been basically unchanged in design for many years, usually lightly loaded. There's nothing there that means that only one oil will do, and it's quite likely that any of the major manufacturers will have several oils that will adequately meet the lubrication needs of a typical manual machine tool such as the type we normally have.

Michael

Originally Posted by Dave J

I am pretty sure you will find Super cheap only have 68.

Dave

I'm using ISO68 that I got from a Super Cheap out my way (they only had ISO68). I was at another Super Cheap store on Saturday and that store had 32, 48 and 68 in stock so I guess it depends on the particular store.

Realistically engine oil would do OK...But hydraulic oil would be cheaper...

I doubt there would be any issues no matter what you use given the machines age...