Printed from Kezuriba (kezuriba.net/en/maintenance/grinder/lubrication/)

Grinding machine lubrication

Where to lubricate, oil types and viscosity (ISO VG), and replacement guidelines. Intervals, oil types and values: the specifications of the grinder and wheel makers, and the markings on your own machine and wheel, come first. The values here are examples found in public documents, so always check the instruction manual. Changing grinding wheels and the trial run after a change must be done by someone who has had special training (Japan)

⛽Lubrication points and oils

Location	Machine	Oil (example)	Interval guideline
High-frequency spindle for internal grinding	Internal	Lubrication method, lubricating oil, oil supply rate, and air pressure and flow given on the spindle's specification sheetSeiko Instruments' internal grinding spindles come in an oil-and-air lubricated type and a grease-lubricated type that eliminates air consumption and mist	Always use under the specified conditions^[12][13](1 source, for reference)
Bearings of the wheel spindle	Common	The machine maker's specified oil. For high-speed spindle bearings, spindle oil (bearing oil) of ISO VG 2–22 is used (Mobil lists grinding machines among its applications, and Idemitsu offers VG 2, 5, 10 and 22 of JIS K 2239 bearing oil)JTEKT (Koyo)'s technical guide to bearings gives the wheel spindle of a grinder as an example of forced-circulation lubrication. The oil lubricates and cools the bearing, returns to the tank, is filtered and cooled, and is sent out again. Make the drain pipe about twice as thick as the supply pipe. JTEKT has a cylindrical grinder model that cools the wheel bearing oil to shorten warm-up time	Depends on the lubrication method and model (circulating, oil-air, grease-packed, hydrostatic bearing, etc.)^[1][2][3][4]
Ways (sliding ways) of the table, saddle and wheelhead	Common	The machine maker's specified way oil (or multi-purpose oil)Okamoto's European subsidiary's vertical-spindle surface grinder uses a system that feeds the ways automatically by gravity from an oil reservoir at the top of the column. Way oil prevents stick-slip, the repeated sticking and slipping at slow feeds (ENEOS)	Many models lubricate automatically. The amount and interval depend on the model's instruction manual^[5][6][3]
Hydrostatic ways and bearings	Common	The machine maker's specified hydraulic oil (for hydrostatic use)Hydrostatic ways float the moving part on hydraulic pressure, so friction is very small and neither table lift-off nor stick-slip occurs. In exchange, rigidity and damping are lower than with sliding ways and rolling ways (ENEOS)	Consider servicing the hydrostatic blocks when changing the hydraulic oil and filters (Seiko Instruments)^[7][5][8]
Hydraulic unit (table reciprocating drive, etc.)	Common	Example of Yuken's general hydraulic unit: petroleum-based anti-wear hydraulic oil or general hydraulic oil, equivalent to ISO VG 32 or 46. Tank oil temperature 5–60°C, contamination level within NAS class 10Okamoto presents models with the hydraulic unit placed away from the main body to avoid the effects of thermal expansion and vibration, and models with a hydraulic oil temperature controller as standard. Equipment without a chiller runs hot in summer, so switch to a higher-viscosity hydraulic oil if needed (Yuken)	Oil level and temperature daily. Drain water about once a month. Test the oil properties every 3 months for the first half year, then every 6 months (Yuken)^[9][6][10]
Ball screws and support bearings of the feed axes (NC grinders)	Common	The machine maker's specified oil (from the ball screw lubrication tank on forced-lubrication models)JTEKT presents models with forced lubrication to reduce ball screw and bearing damage when fine carbide or ceramic swarf gets in (consisting of a ball screw lubrication tank, a slide lubrication tank and a waste oil can). Ball screws can rust on machines left idle for a long time (Seiko Instruments; especially on machines with water-soluble grinding fluid)	Check the oil level in the lubrication tank (interval depends on the model)^[4][11]

🛢Oil types and how to choose

Spindle oil (bearing oil)ISO VG 2–22 (Idemitsu: JIS K 2239 bearing oil VG 2, 5, 10, 22. Mobil's Velocite lists VG 2–22 for high-speed spindle bearings and grinders): Lubricates the bearings of wheel spindles and internal grinding spindles that turn at high speed. A low-viscosity oil. Use the viscosity and brand the machine maker specifies^[3][2]
Way oilAs specified by the machine builder: Lubricates sliding ways. Prevents stick-slip and maintains feed accuracy. Some grinders with hydrostatic ways use hydrostatic (hydraulic) oil^[5][3]
Hydraulic oilISO VG 32 or 46 is common for general hydraulic units (Yuken example): Hydraulic drive of the table and supply to hydrostatic parts. When switching to a different brand, flush thoroughly with the new oil's flushing oil before changing. Some seal materials cannot be used with certain types of hydraulic oil (Yuken)^[9][3]
Water-soluble grinding fluid— (concentrate diluted with water. Dilution ratio per the product's recommendation): Strong cooling and easy to handle. Used for much surface and form grinding (UNITED GRINDING). Dilute by adding the concentrate to the water (doing it the other way round can cause gelling and make it hard to dissolve, Noritake). Bacteria and mold grow easily, so it needs management. Choose a fluid that does not corrode the brass and resin of the magnetic chuck separator (Kanetec)^{[14][15][16][17]}
Neat (non-water-soluble) grinding oil (oil-based)—: Good lubrication; suited to grinding carbide and HSS, and to diamond and CBN wheels. Keeps the machine clean. Choose an oil with a high flash point. Machines that use oil-based grinding fluid need fire-extinguishing equipment and an oil cooling unit (UNITED GRINDING). The SME article (by a Norton engineer) recommends high-performance ester-based grinding oil for centerless grinding^[15][16][18]

📚Sources

Items without a mark are those on which two or more materials from different publishers agree. Values and intervals are governed by each machine's specifications. The text is summarized in Kezuriba's own words.