How To Choose The Right Lubricant For The Grinder And Which One To Use In The Gearbox

2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54

• The main characteristics of a lubricant for angle grinders
• Lubricants recommended by foreign tool manufacturers
• Lubricants of domestic manufacturers for bearings and gearboxes of grinders
• Grease for bearings LBM
• Lubricant for the LBM gearbox
• DIY grease for the grinder gearbox
• Correct grease filling process in angle grinders
• When to change the lubricant in the grinder
• How to properly remove old grease in a grinder
• The procedure for applying grease to the grinder gearbox
• What amount of lubricant should be used when replacing the angle grinder in the gearbox
• Control of the correct application of lubricant to the LBM gearbox
• Grinder repair video

Angle grinders (angle grinders), popularly called grinders, are widespread among lovers of tinkering. With their help, the home craftsman can not only perform grinding work, but also cut metal, plastic, stone. Angle grinders are produced by various manufacturers, including domestic ones.

The angle grinder is a reliable tool that can work with correct operation and timely replacement of lubricants and carbon brushes for a long time.

Correctly selected grinder grease not only extends tool life, but also improves performance.

Knowing the rules for choosing a lubricant for a grinder or making it with your own hands, you can perform maintenance without contacting a service center.

The main characteristics of a lubricant for angle grinders

In angle grinders, the main unit subject to the greatest loads during operation is a gearbox consisting of helical gears.

The torque generated by the grinder's rotor is transmitted from the rotor to the working tool through a small helical gear to a large helical gear. The correct lubricant for the gearbox significantly reduces frictional force and heating temperature.

The grinder uses bearings, which also require periodic lubrication. This especially applies to the spindle bearing of the large helical gear.

A lubricant that meets not only the listed requirements, but also environmentally friendly is suitable.

Lubricants for an angle grinder must have certain characteristics and must be of the required consistency in terms of properties.

Lubricant for the angle grinder gearbox must have:

• viscosity no more than 800 Pa · s;
• dropping point not less than + 120ºС;
• ultimate strength not less than 120 Pa.

Lubricant for angle grinders should not have mechanical impurities, be resistant to corrosion, adhere firmly to the lubricated parts, not melt at high temperatures, prevent the formation of scoring at the contact points of parts and, of course, have water-repellent properties.

In an angle grinder of any company, two types of plain bearings are used: bearings for an electric motor and support bearings for a gearbox.

The selection of grease for the bearings of an electric motor is different from the selection of grease for the gearbox bearing. It's all about different working conditions.

Lubricants recommended by foreign tool manufacturers

Foreign tool manufacturers, including angle grinders, recommend specially developed ointments as lubricants for grinders.

One of the most widespread foreign greases is the grease marked MoS2 NLGI 2 ISOL-XBCHB 2 DIN 51825-KPF 2 K-20.

Let's decipher the marking:

1. MoS2 indicates filler material, in this case molybdenum;
2. NLGI2 - indicates the second viscosity grade;
3. ISOL-XBCHB 2 - belonging to ISO standards;
4. DIN 51825-KPF 2 K-20 - the grease is made according to German DIN standards;
5. The numbers 51825 indicate that the grease is type K.

Lubricants produced with such characteristics are quite expensive. There are imported, less expensive lubricants on the Russian market.

Each tool manufacturer, be it Bosch, Makita, Hitachi, DeWalt, Metabo, RedVerg, Interskol, E256, LEPSE, recommends its own lubricants. This is the manufacturer's policy. They insist that the lubricants specified in the instructions are used when performing maintenance. Moreover, non-observance of these recommendations does not allow performing warranty repairs.

Makita grease for the Makita lumbar gearbox is available in tubes. Its high cost is commensurate with its high quality and long service life.

Lubricants of domestic manufacturers for bearings and gearboxes of grinders

With the rise in prices for foreign lubricants, lubricants from domestic manufacturers have become especially in demand.

Russian lubricant manufacturers have learned how to produce high quality lubricants suitable for any tool.

Lubricants have been developed for reducers of grinders, perforators, drills.

The products of Nanotech Metal Plak Electra are especially popular. The range of lubricants produced by this company allows you to select the lubricant required for each unit

Grease for bearings LBM

The design of the angle grinder has three bearings. Two bearings are mounted on the rotor of the tool, one bearing is mounted on the shaft of the driven helical gear with a larger diameter.

In angle grinders, bearings are used that are already filled with grease. But from improper operation, overheating of the tool, grease flows out.

How to choose the right grease for grinder bearings?

The bearing grease must meet the following requirements:

• increase sliding;
• reduce friction between component parts of parts;
• evenly distribute heat and act as a coolant;
• prevent the occurrence of corrosion;
• protect from dirt and dust getting inside;
• work in the required temperature range up to + 150C;

The operating conditions of the electric motor bearings differ from the operating conditions of the gearbox bearing, not only because of the temperature requirements, but also because of the operating modes, load modes, frequency and speed of rotation.

The lubricant for the bearings of the electric motor must have protective properties that prevent the ingress of dirt, dust and moisture onto the bearing parts.

The Russian market offers a wide range of foreign greases designed for bearings operating under different conditions. But their cost makes them look for cheaper, not inferior in quality, domestic lubricants.

Among domestic lubricants, we recommend paying attention to the Tsiatim-221, VNIINP-246 (GOST 18852-73), VNIINP-235 lubricants.

Lithium greases have proven themselves well.

Possessing high water-repellent properties, they have a wide temperature range. The role of the thickener in them is played by organic and inorganic substances. For sealed bearings, it is best to use CIATIM-203, VNIINP-242 greases.

Of the pigment greases for electric motor bearings, blue grease VNIIMP-246 and dark purple ointment VNIINP-235 have become widespread. The first lubricant, due to its high price, is less common than the second.

In today's Russian market, domestic manufacturers of lubricants are represented in a wide range of products.

Lubricant for the LBM gearbox

Grease for the grinder gearbox differs from grease for bearings in the main feature - increased adhesion. It should firmly adhere to the gearbox teeth with a large rotation.

In general, the lubrication process of the gearbox in angle grinders occurs due to a fine spray of lubricant and its suspensions. The gearbox works as if in oil mist. Therefore, the lubrication requirements for gearboxes are slightly different.

In addition to increased adhesion, the gear lubricant must be highly heat resistant and not melt at elevated temperatures.

DIY grease for the grinder gearbox

Although the listed lubricants of domestic production are affordable, they are not always at hand.

Is it possible to make do-it-yourself lubricant for the gearbox of an angle grinder

And there is an affirmative answer to this question.

Since the main technical characteristics of lubricants for LBM gearboxes are presented above, they can be taken as the basis for making a lubricant of the desired characteristics with your own hands.

Homemade gear lubricant should be based on a highly adhesive lubricant. It must hold firmly to the touching parts.

Grease for CV joints has increased adhesion. SHRUS is a joint in a front-wheel drive vehicle that works in conditions of increased pollution, shock loads, temperature fluctuations and humidity.

Taking grease for CV joints as a basis, it is necessary to add liquid grease (MS-20) to give the mass the desired consistency. Oil MC-20 should be served drop by drop, thoroughly kneading the mass using a homemade mixer.

Good results are obtained by a mixture of a mixture of Tsiatim-221 and TAD-17 lubricants, where Tsiatim is the basis.

Correct grease filling process in angle grinders

Packing grease into the units of an angle grinder has its own rules. You need to know not only the order of its application, but also how much, and where to lay it.

When to change the lubricant in the grinder

The grease on the grinder changes according to the tool maintenance plan, when replacing failed gearbox parts or rotor bearings.

Old grease is dirty and dark in color. This is due to the ingress of foreign particles of metal or dust into it.

How to properly remove old grease in a grinder

Old grease is always removed completely, regardless of its color. There should be no traces of old grease on the parts, and there should be particles of destroyed parts in the cavities of the body.

To remove old grease, you can use various flushing fluids used by motorists to wash the engine and its parts. At home, it is recommended to use kerosene or a solution of kerosene and gasoline.

All parts and their cavities must be thoroughly washed and dried.

The procedure for applying grease to the grinder gearbox

The new grease is thoroughly mixed before application and applied in a thin layer. The bearings are lubricated by packing. If the grease is in a plastic tube, the neck of the tube is pressed against the side bearing cage and squeezed out until it flows out of the back.

What amount of lubricant should be used when replacing the angle grinder in the gearbox

If the amount of grease in the bearings is controlled by flowing it out from the reverse side, then a certain amount of grease is stuffed into the angle grinder gearbox. Excess grease will leak out during operation. And a small amount of it will not ensure high-quality operation of the gearbox.

Leave as much lubricant in the gearbox as needed to cover the gear teeth.

Apply enough grease as a guide so that it occupies slightly less than half the volume of the gearbox cavity.

Control of the correct application of lubricant to the LBM gearbox

Control of the amount of lubricant stuffed into the gearbox is carried out by testing the assembled grinder for a short time at idle mode.

If the gearbox begins to warm up, traces of grease leakage appear from the oil seals and gaskets, then the conclusion is clear. You have shifted the grease. Open the gear case and remove excess grease. Any excess grease will be placed on the gearbox housing covers. An insufficient amount of lubricant in the gearbox is determined by the increased noise of the gearbox.

With long-term operation of angle grinders, the lubricant in the gearbox is distributed on the walls of the case and loses its properties from external influences.

Having opened the gearbox cover, carefully inspect the condition of the lubricant, the tooth profile of the gears. If you can, check the contact patch of the gears.

The presence of dry or dried lubricant particles in the area of the gearbox or on the housing indicates that the time to change the lubricant has come.