Machine tools feature a number of intricate moving parts, and lathes are no exception. There’s the motor in the lathe headstock driving the spindle, which may rotate thousands of times per minute.
Add to that the slide for the tailstock on the lathe bed, and you’ve got lots of moving parts all generating friction – and in theory, needing some oil to keep things moving.
So which oil to use? Do lathes require specialized oils, and if so, what makes them special? In this post, we’ll cover a bit about lathe oils, what they are, and how to use them.
DIFFERENT OILS FOR YOUR LATHE
The short version first: you can’t just drop some old car engine oil into your lathe and call it good. You’ll want a particular viscosity on your oil, and you’ll want it to a particular standard.
Those standards are set by the International Standards Organisation (ISO), and the same standards apply across the industry. This simplifies things a bit; you just need to determine what viscosity oil you need for your lathe, and find an oil that matches that standard.
What is the recommended viscosity for lathe oil? The preferred standard for most machinists is ISO 68 hydraulic, non-detergent gear oil. Confused? Let’s break it down a bit.
As mentioned, this refers to the viscosity of the oil, as measured against ISO standards. The right viscosity of the oil is critical to ensure that the oil reaches all the necessary parts and keeps them moving smoothly.
Hydraulic oils and hydraulic fluids help the transfer of power in hydraulic systems. They also are typically mineral-oil based. Mineral oils are derived from petroleum, but by a slightly different process – typically a distillate process.
The engine oil in your car likely contains a number of additives, known as detergents. These additives are intended to help keep the engine running clean and clear by attracting any stray particles and allowing them to be caught by the oil filter. This system works well in most automobiles but isn’t ideal on smaller and more delicate motors. Non-detergent oils are free from any additives.
Add all this together, and what do you need for your lathe? An oil with a fairly heavy viscosity, ISO 68, mineral-oil based, intended for use in hydraulic systems, and without any additives.
LATHE OIL AND MAINTENANCE TIPS
- Don’t use grease!
Avoid using grease on your lathe. Grease will attract shavings and cuttings, trapping them against your lathe and causing gunky build-ups and extra wear. If you see something that looks like a grease nipple, it’s almost certainly for oil instead.
- Use some grease!
I know – we just said the opposite! There is one part that might require some grease from time to time – the main spindle, where it passes through the bearings on the headstock. Most instruction manuals will call for a small amount of grease on this part but use it sparingly.
- Slideway oils
The ISO 68 oil appears to be the most commonly-accepted lathe oil for headstocks. Slideways on the lathe bed may require something a little bit lighter, to prevent any sticking in the middle of a delicate adjustment. Try your ISO 68 oil first, however, in case it does work and you can save the hassle of purchasing an entirely different oil.
When it comes to particular brands of lathe oil, you’ll find that every machinist worth his or her salt will have their own preferred brand. At the end of the day, however, getting the viscosity correct matters much more than the brand.