Repair and construction

Disks for the Bulgarian: what are the types, dimensions, how to change correctly

January 21, 2020

Angle grinder (KSHM), popularly called "Bulgarian", widely used in construction and in everyday life during repairs. With its help you can perform many different technological processes. To choose the right tool to perform a certain type of work, it is necessary to get acquainted with that, what are the disks and nozzles for KShM. The tool for this device is selected by size and purpose.

Typical disk sizes

When choosing a disc for the Bulgarian must be traced, so that the outer diameter of the nozzle does not exceed the maximum allowable values, allowed for your angle grinder. For example, if the Bulgarian is designed to use a circle with a maximum diameter 125 mm, then you can set a circle on it 230 mm. And there are several explanations for this:

  • the linear speed of the cutting edge will be exceeded, which threatens to destroy the abrasive wheel and injure the user;
  • the little Bulgarian woman does not have enough power, to work with a great tool;
  • nozzle installation, exceeding the allowable dimensions, requires removal of the protective cover, and this is a violation of safety rules.

Disks for USHM have standard sizes: 115, 125, 150, 180 and 230 mm. In modern Bulgarians landing diameter (shaft diameter, on which the tool is installed) almost the same and equal to 22,2 mm. If you are overwhelmed "Bulgarian obsolete model, then you need to use adapters - rings of different diameters.

All abrasive wheels of any size have special markings, from which you can find the following information: the diameter of the disk and its thickness, landing diameter, maximum speed of rotation, as well as for the processing of which materials it is intended.

Purpose of disks and nozzles

Circles for the Bulgarian differ in purpose on:

  • detachable;
  • peeling
  • grinding;
  • sharpening.

Cutting discs

The most common task, performed with the help of a Bulgarian, there is cutting of different materials. From that, what material needs to be cut, depends on the choice of tool material.

  1. Metal cutting. The metal cutting disc is made of crystalline alumina corundum, as well as synthetic corundum, called electrocorundum. The main color of circles for cutting metals - blue.
  2. Cutting stone and concrete. To cut the stone, choose a disc made of another abrasive material - silicon carbide. This abrasive easily cuts white brick (silicate) and slate. But to cut red bricks, some types of concrete or ceramic tiles, this circle material will not fit. Stone discs are available in green.
  3. Cutting ceramic tiles, red brick, porcelain and concrete. A diamond disk is already used for this purpose.

    This nozzle is made of metal, abrasive mass with diamond crumb is applied to the cutting edge. The figure shows the segmented saw wheel above, designed for dry cutting of material. All-metal discs require water cooling during operation.

  4. Cutting wood. Although there are saws for wood on sale, which are no different from circular saw blades, it is better to abandon their use for security purposes. When working with such a tool, the user often suffers serious injuries due to jamming, dap, accidental slipping of the tool, etc.. d.

So, if you are going to use a saw blade on wood, then safety precautions should be followed. A protective cover and a handle must be installed on the Bulgarian, the user is required to wear a protective mask or goggles. in addition, materials cannot be cut with this tool, not intended for him.

Wood disks are considered the safest, on the end face of which the chain from a chainsaw is established. In case of jamming of the tool, the chain remains in place, and the disk rotates idle, which reduces the likelihood of user injury.

Peeled

If you need to remove a layer of paint or other task, as well as rust from any surface, korschets are used. They are disk or in the form of a bowl with a built-in metal wire.

The wire in the nozzle data can be twisted or loose. Its thickness can also be different. The thicker the wire, so for rougher peeling used peeling disc or cup-shaped nozzle, and vice versa.

Grinding

For grinding and polishing various surfaces (metal, wood, plastic and others) grinding wheels and nozzles are used. A petal-type grinding wheel is often used for grinding. It consists of many "petals", made of sandpaper. You can choose the grain size of the sandpaper, based on the required type of processing (finishing or rough).,

Also, the sandpaper can be attached to the nozzle with Velcro. Such a tool screws on the spindle USHM.

Special circles and nozzles are available for polishing surfaces, that look like felt pillows or fabric discs.

Sharpening

To sharpen a tool, grinders are usually used (powder). But if you do not have the latter, but there is a Bulgarian, then you can buy a sharpener for it (grinding) circle, which can easily lock almost any cutting tool.

The main difference between sharpening wheels and cutting wheels is their thickness (no less 5 mm).

How to properly change the disk on the Bulgarian

Because circles for Bulgarians are consumables, sooner or later they have to be changed. They are attached to the spindle USHM with a clamping flange (nuts) with M14 thread. To unscrew it, in a complete set to the Bulgarian there should be a special horn key, having pins on one side.

so, to replace the tool on the Bulgarian, follow these steps.

  1. Disconnect the appliance, pulling the plug out of the socket.
  2. Secure the USHM spindle with the button, located on the front of the case. When you press the button, the stopper enters the hole in the disc, installed in the gearbox, than fixes the spindle in a stationary position.
  3. Insert the key pins into the holes on the clamping flange.
  4. Holding the latch with one hand, with the other hand turn the key to the left (counterclockwise), until the nut breaks. Then it can be unscrewed without a key and removed from the shaft.

    In this case, the spindle USHM rotates clockwise. But in which direction to unscrew the nut, if your machine rotates the shaft counterclockwise? Remember: the clamping flange should always be unscrewed in the opposite direction of rotation of the shaft.
  5. You can now change the tool, having previously removed the old one.

    If you noticed, that dirt has accumulated inside the casing, then remove the lower flange and use a steel brush to remove dirt from all surfaces.

  6. Further, the lower flange must be replaced. You need to put it right, be sure to connect the grooves on the spindle and flange.
  7. Place the gasket on top of the lower flange. It is not necessary to put it, but desirable, as it will provide easy unscrewing of a clamping nut further, if you need to change the tool.
  8. Install a new tool. Sometimes the owners of USHM ask questions: which side to put the circle? The answer is simple: the disc is placed with the marked side facing out.
  9. Place the gasket on the abrasive wheel. If your Bulgarian did not come with gaskets, then they can be purchased at a specialty store, or cut out of thin tin or cardboard.

  10. Screw the flange onto the shaft by hand. Tighten the nuts until then, until you can no longer turn it without a key. After this, holding the stopper, tighten this nut with a wrench, but no more, than a quarter turn, otherwise the disc will start to deform.

After carrying out the above-described actions replacement of the tool is considered suspended.

Promotion methods, if the drive is jammed

What shall I do, if the clamping flange is jammed? This trouble, when bitten by a nut, often happens, if the tool is jammed in the workpiece when working with thick and strong materials. The abrasive wheel often breaks, and continues to rotate the spindle tightly tightens the clamping flange. To promote the Bulgarian, if the disc is clamped, there are several ways.

With a gas key

This method is not considered completely safe, because you can break the stopper, although in most cases, it is possible to unscrew a nut. In order not to break the spindle lock, do not apply much force to the gas key. The design of the clamp is designed for effort, attached with a standard key.

Excessively clamped flange can be unscrewed with 2 gas wrenches. To do this, break off the protruding ends of the abrasive wheel with pliers, so that the first gas key can reach the lower flange. Further, clamp both flanges with the wrenches and turn them in opposite directions (given that, which thread on the spindle - right or left).

Disassembly of the gearbox

If, when the latch is broken, to remove the tool from the angle grinder, will have to disassemble the gearbox. Break off the remaining abrasive wheel with pliers, so that you can get to the bolts, holds the gearbox cover. Then unscrew the fasteners and open the gearbox. The cover will be extended together with a gear shaft. Further, this shaft should be clamped in a vise, pre-laid between the steel jaws aluminum gaskets, and unscrew the flange with a gas wrench (do not forget to determine the direction of unscrewing).

Heating the nut

The nut can be heated with a gas burner, construction hair dryer or blowtorch. The heated flange is usually unscrewed with a standard wrench for the Bulgarian.

Grinding jammed circle

If after application of the first 3 ways the nut is not unscrewed, then the remaining abrasive wheel between the flanges can be ground. To do this, do the following.

  1. Remove the remnants of the circle along the edges of the nut with pliers as much as possible.
  2. Clamp a piece of sheet iron of this thickness in the vise, like the drive itself, turn on the Bulgarian and grind the remnants of the circle about the end of the sheet iron.

Instead of iron, you can clamp a piece of abrasive wheel. In this case, grinding of tool residues between the flanges will be faster, and the nut can be unscrewed by hand.

But the use of a fixed abrasive wheel requires great care, after all, when grinding the remnants of the tool, you can damage the geometry of the flange. If this happens, will have to face the nut.

Use of penetrating lubricant

Pour WD-40 fluid over the flange joint. It has the ability to penetrate into the inter-threaded spaces and small cracks. After applying the liquid, wait close 5 minutes and try unscrewing the fastener with a standard wrench.

With the use of a perforator

Some Bulgarian owners are in a situation, when the clamping nut jammed, install a perforator nozzle "chisel" or "jackhammer", insert it into the hole of the flange at an angle and turn on the jackhammer without rotation. In accordance, the stop button must be pressed. Just a couple of light presses with a punch (so as not to break the shaft lock), and the nut will start to turn.

Cut the clamping flange with a hacksaw

This method can be called radical, because you have to buy a new mount, and it applies, if the nut is not unscrewed by any other methods. To saw the flange, press the stop button, so that the shaft does not rotate, and, using a hacksaw on metal, cut the mounting nut.