What kind of grease to use for the gearbox of an angle grinder

The correct process for changing the grease in the gearbox of the angle grinder

To change the grease for the angle grinder gearbox, proceed as follows:

  • Unplug angle grinder’s power cord.
  • Remove the wheel.
  • Loosen the fastening screws and remove the gear cover.
  • Clean the surface of grease residue.
  • Remove spindle with pinion and bearing.
  • Wash the parts with gasoline and dry them.
  • Apply a new coat of grease.
  • Assemble the gearbox and install it in an angle grinder.

Other information! If grease residues are seeping out through the spindle, remove them with a clean cloth.

Gear lubricant for angle grinder

Almost all world manufacturers require their recommended lubricant under their brand name. This is basically correct. the grease used for the gearbox of the angle grinder, in this case is tested in the factory, it gives a guarantee of long-term and correct operation of the angle grinder. However, there are disadvantages, which lie in the high price of lubricant from these brands.

grease, gearbox, angle, grinder

In addition to the original oils, there are many lubricants on the market, manufactured by third-party manufacturers, so the question of what exactly to lubricate the gear reducer of an angle grinder is not acute.

Products from Haskey, Castrol, Liqui Moly and others showed themselves well for addition to the gearbox of angle grinder.

Russian manufacturers also do not lag behind foreign ones and offer their products. Thus, the lubrication of the bevel gearbox of the angle grinder from. Of course, such grease for the gearbox is not original and recommended by the manufacturer, so in the case of its use, the subsequent warranty repair can simply refuse.

How to lubricate the gearbox: the sequence of operations

Maintenance of angle grinder. a very simple procedure, but it requires removing the device. If the instrument is still under warranty, it is better not to risk and seek help from professionals who will quickly and inexpensively perform all necessary operations.

Lubrication is carried out in several stages:

  • disassembly of the tool;
  • thorough flushing of all parts and internal cavities of the gearbox. For this purpose, you can use gasoline or kerosene to effectively remove any dirt;
  • drying of machined elements;
  • applying lubricant after mixing it thoroughly;
  • assembly of the device and test run.
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If you do not hear any unusual noises or see leaks of lubricant while idling, you can safely use the angle grinder for your purposes.

Worth the trouble or not, pros and cons

Before you start making homemade grease, think about whether such an activity makes sense? What extreme necessity makes you ignore the manufacturer’s recommendations and fill the gearbox of the grinder with a “homemade” mixture of components, originally designed for other mechanisms?

A close analogue of the angle grinder gearbox is the constant velocity joint (CVJ), a critical component of a front-wheel drive car. Transmits high torques in difficult temperature conditions, with high rotational speeds. Parts of a working joint come into contact with each other under conditions that, in the absence of a lubricating film, lead to local welding. By the way, the same effects occur in helical or hypoid gears of bolster gearboxes.

There were times when many people set a goal to replace factory C.V. joint gear lubrication with homemade one. The most common recipe was simple and accessible. We take Lithol-24 and generously add friction modifier, for example molybdenum disulfide (available in chemistry shops now, inexpensive). Of course, stir thoroughly with a wooden stick. Heat mixture and put into joint with a syringe, piercing a needle through the rubber cover.

Such “useful” tips were very popular in the former USSR in the late 80’s, when the first VAZ cars “eight” and “nine” faced the problem of lubricating the joints. Or rather, with the scarcity of grease for them. And there were those who followed such advice, and then shared their experience. Very sad experience.

Ultra gear lubricant for power tools is suitable for angle grinders. Photo AllInstruments.Ru

Let’s return to our grinders. What an extreme, inexorable necessity requires the use of homemade (surrogate) lubricants? If in the midst of work your angle grinder absolutely requires lubrication, use any available grease at hand. Also Lithol-24 and CYATIM-221 (better 221F) will do. Any of these would also work, but luckily for angle grinders, it is no longer available. We repeat. any grease will do, but it should be evaluated as a surrogate, not as an analogue.

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All procedures must be followed to remove any residual grease from the gearbox. Not being bothered about the lack of antifriction and extreme pressure additives in the surrogate, finish the urgent work with an angle grinder. Cut off that corner or sheet of corrugated sheeting. Or a crumpled up car fender, the tough owner of which demanded: “It must be ready in the morning. After that, go look for and buy the original grease or a quality analogue from other manufacturers. Remember that the measure taken is a temporary one, necessitated by an absolute necessity.

Before you put the original or analogue grease back into the gears, don’t forget to clean and wash the gearbox from the lumps of black sludge that the used surrogate has turned into. When you pick at the sludge with a wooden stick with metal dust from worn gears, think about whether you need to invent a homemade lubricant. Not everyone can create a quality analogue, and all substitutes have already been invented.

By the way: domestic “Grease 158”, ShRUS-4, G-Energy Grease, designed for constant velocity joints, works very well in the gearboxes of bucking machines. There are three disadvantages:

  • Low viscosity. Once heated, grease flows out of the gearbox through the gap between the cover and the spindle.
  • Contains additives that are aggressive to non-ferrous metals. Gearbox housings of all angle grinders are made of aluminium alloys. Some models have bronze-graphite spindle bearings.
  • Low moisture resistance, highly hygroscopic. Geared motors of angle grinders have no hermetic seals.

Main characteristics of the lubricant for angle grinders

Gearbox in angle grinders is the main component subjected to highest loads during operation, it consists of helical gears.

The torque generated by the rotor of the angle grinder is transmitted from the rotor to the work tool through a small helical gear to a large helical gear. Correct gear lubricant reduces friction force and heat build-up significantly.

The grinder uses bearings, which also require periodic lubrication. Especially it concerns the bearings of spindle bearings of large helical gears.

Harbor Freight Drill Master Angle Grinder Gearbox Grease Replacement

A grease that not only fulfils the above requirements, but is also environmentally friendly is suitable.

Angle grinder lubricants must have certain characteristics and be of the required consistency.

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Angle grinder gear lubricant must have:

Grease for the angle grinder must not have mechanical impurities, be resistant to corrosion, firmly adhere to the lubricated parts, do not melt at high temperatures, prevent the formation of scuffing in the contact areas of parts and of course have water repellent properties.

Two types of friction bearings are used in angle grinders from any company: motor bearings and support bearings for the gearbox.

Selecting a grease for electric motor bearings is different from selecting a grease for a gearbox bearing. It’s all about different working conditions.

Liquid lubricant

Similar to conventional motor oil for cars. It is used in gearboxes with hermetically sealed housings. Rotating shafts in these units are sealed with oil seals that keep the oil inside them.

Greasing is accomplished via holes, which are then sealed. The system is very effective, because the gears and other friction-prone elements are evenly coated with an antifriction compound.

In addition, the working fluid acts as a heat sink and cools the gearbox by getting in contact with the housing walls. But there is a disadvantage: When the sealed gearbox housing heats up, the pressure increases.

Since there is no breather plug (as in a car engine crankcase), grease squeezed out through the glands may be lost.


Much more widespread, because of the ease of use. Has a thick consistency and good adhesion. To be applied to gearbox parts when the latter are dismantled.

Easy to control the amount of grease. When cold, the grease is thick enough to remain firmly attached to the gears. After assembly, complete tightness of the gearbox is not required, quality gaskets and shaft sealing sleeves are sufficient.

When the gearbox is running, when the gearbox heats up, the viscosity of the grease reduces and it spreads evenly over the surface of the parts. The grease will thicken and stick to the gears again after cooling.

Properties of gear lubricating greases

Standard thick general purpose oils are not suitable for a geared motor vehicle. Similar parameters have only compositions for automobile CV joints.

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