Hydraulic oil for CNC machines — the oil in the hydraulic unit that clamps the chuck, moves the tailstock and locks the turret. Most CNC lathes and machining centers run an anti-wear ISO 32 hydraulic oil (AW 32, HLP 32); some machines and warmer shops call for ISO 46.
We supply hydraulic oil to order in 5-gallon pails and 55-gallon drums. Tell us your machine and the grade in its manual, and we will quote it.
On a CNC lathe the hydraulic unit clamps the chuck or collet, drives the tailstock and, on many machines, unclamps and locks the turret. On machining centers it often clamps the tool in the spindle, changes pallets or works fixtures. In all of these, the oil carries pressure, lubricates the pump and valves, and has to stay free of air, water and dirt — a small change in pressure is a change in clamping force on the part.
Start with the machine manual or the plate on the hydraulic tank — the builder has already chosen the grade for the pump and the valves. As a rule:
Do not change grade on your own: a thicker oil makes the pump work harder at start-up, a thinner one can leak past seals and let clamping pressure drift.
AW (anti-wear) is the North American name, HLP the German one (DIN 51524-2), HM the ISO one. All three describe a mineral hydraulic oil with anti-wear, anti-rust and anti-oxidation additives. So hydraulic oil AW 32, HLP 32 and HM 32 are interchangeable on most machines, as long as the viscosity grade matches. Manuals from European builders usually say HLP, North American ones AW.
Hydraulic oil and way oil sit next to each other on the same machine but do different jobs: way oil is tacky, made to stay on the slideways; hydraulic oil must release air and flow freely. Filling the hydraulic tank with way oil, or the way oil reservoir with hydraulic oil, causes problems in both systems.
Looking for way oil, cutting oils or coolants? See all metalworking fluids.
