Practically every home craftsman has among the tools a homemade emery of an electric motor. With it, you can sharpen various necessary things in everyday life. You can, of course, buy such emery in the store. However, its cost is often very high. Therefore, craftsmen and make homemade emery.
For the manufacture of emery need an asynchronous motor from a Soviet washing machine.
For such a device is very important to choose the right motor. Special nozzles are mounted on its shaft, which clamp the emery wheel.
How to choose the right motor for the device
In Soviet times, produced a lot of models of washing machines. They were equipped with powerful engines having a reverse. In addition, such a washing machine had a switch equipped with an actuator.
The most difficult in the layout of homemade emery, when you install such an electric motor, is the process of attachment to the axis of the abrasive stone. The motor shaft in most cases does not have a thread, the diameter of the hole in the stone often does not correspond to the diameter of the shaft.
To solve this problem, you need to turn a special part. It must compensate for this disparity. For the manufacture of homemade emery it is necessary to plan the future dimensions of such a part. Most often, homemade sandpaper is made using an asynchronous motor.
The basic scheme of emery.
To emery had high performance, the engine must develop 3000 revolutions. If this number is much higher, then the grinding stone may break. Therefore, to prevent the possibility of such a breakdown, an electric motor is used for the house, which develops 1500 revolutions. For an electric motor with 3000 revolutions, it is necessary to use a high-strength stone. It must be attached with a very high quality and reliable flange. Most often, large revolutions are needed for polishing products. On such devices, sharpening occurs very rarely.
When homemade emery is made, you do not need to install a powerful electric motor. Professionals recommend using a 400 W motor power for a stationary grinding machine. To work in the garage, it is enough power of the electric motor is not more than 200 watts. It was such a washing machine. One of its positive qualities is low speed.Back to table of contents
The main purpose of the work
Before you make sandpaper, you must clearly represent the future direction of its operation. Usually homemade emery has the ability to change the direction of rotation of the rotor. The Soviet washing machine was equipped with an asynchronous motor. This allowed changing the axis rotation when connecting certain windings. Sometimes the engine has four leads specifically for changing the rotation of the rotor.
To find out the desired direction of rotation, the tester determines:
- working winding;
- start winding.
Diagram of the device emery.
The indicator of the resistance of the working winding in most cases does not exceed 12 ohms, the starting one reaches 30 ohms. The working winding is connected to the mains. One end of the starting winding is connected to the output of the coil, the other end of it must touch the second output of the winding, and having touched it, it should be immediately discarded. Usually for such an operation a special relay is used.
This determines the direction of rotation of the emery. If the winding pins are swapped, the engine will begin to rotate in the other direction. Sometimes do not put the start coil. To get started, you just need to spin the grindstone, the grindstone will start working.
Back to table of contents
Turning work: features
To be able to fix the stone on the engine axis, it is necessary to turn a special flange.
This work is done on a lathe. Pre-made drawing, which necessarily indicates:
- diameter of abrasive, its internal opening;
- diameter of the motor axis.
In addition, the flange for the motor shaft is also machined on the machine. It is put on the axle, it is securely fastened with a bolt joint, and a nut having a left-hand thread is installed.
Threading nuts, flange threads directly depends on which direction the rotation of the motor shaft will be directed. For rotation in the direction of the hour hand, left-handed thread is cut, for opposite rotation - right-handed.
When the desktop emery is turned on, spontaneous tightening of the nut will begin. This nuance must be taken into account. If the nut begins to unwind, the abrasive stone can simply fly off during operation. This is very dangerous, because may cause serious injury.Back to table of contents
Installation of emery: recommendations
After all the work and assembly of the electric motor with a flange and a grinding stone, it is necessary to install it on the joinery table. To do this, take the bracket from the washing machine, after which it is screwed to the table with bolts. Support for the engine is the angle of the bracket. It keeps the horizontal position of the engine. The bracket has a cutout that matches the shape of the engine.
To reduce vibration, the corner is wrapped in rubber. You can simply put a rubber hose on it.
In order for the flying particles of the abrasive disc not to injure the worker, the self-made emery must have a protective casing. It is made of thick sheet metal. Usually taken 2-3 mm. The casing can be in the form of a half-ring rolled from a steel strip.
Directly under the grindstone, galvanized iron is mounted. The dimensions of the sheet are selected individually at the place of installation. It will prevent sparks from entering the workbench. In accordance with safety requirements, any work on such a device must be carried out in special glasses and appropriate clothing.
The protective material may be organic glass, the thickness of which must be at least 5 mm. It is attached with the engine cover. For this purpose weights, having the ability to recline. To make it easier to work on the machine, it is necessary to provide an emphasis on which the workpiece will rest.