DIY belt sander
A belt grinder performs the final processing of parts - their final grinding. The main area of use of the tool is the furniture industry, the processing of wooden parts. But they can also process metal elements using the appropriate abrasive material.
Using a belt-type grinding machine, the surfaces to be treated are leveled, their roughness is brought to the level required before coating. They also eliminate minor defects: grooves, burrs, elevations of surfaces, influxes of varnish, primer. The tool can round corners. It is suitable for machining round and tubular parts.
The working tool in the grinding machine is a tape with abrasive powder deposited on its surface. It is made endless, placed on two rotating drums - master and driven.
The driving drum is driven by an electric motor, which transmits rotation to it due to a belt drive. The tape can be placed vertically, horizontally, at an angle. The machine has a device for controlling the speed of the tape.
Having decided to make a belt grinding machine yourself, you need to decide: with the maximum length of the surface to be machined in detail; which table to make (movable, motionless) or to prefer a free ribbon and refuse to make a table. In the design of the machine, it is necessary to provide an exhaust device to remove a large amount of dust that is generated during its operation.
The main parts of the belt-type grinding machine, which will have to be prepared or made, are: a bed, an electric motor, rollers. A motor, for example, comes from a washing machine that has already reached the end of its useful life.
The bed of the future machine can be made of sheet metal - its dimensions can be, for example, 50x18x2 cm. One side of the plate is made even - this is necessary due to the attachment of a platform with an electric motor to it. The platform for the motor is made metal in the form of a plate measuring 18x16x1 cm and attached to the bed with several bolts.
The electric motor used has a power of 2.5 ... 3 kW, is capable of providing a rotation speed of 1500 rpm. The speed of movement of the belt during grinding should be 20 m / s. On this basis, the diameter of the pulleys is made equal to about 20 cm. Under such conditions, in the craft, you do not need to arrange a gearbox, which makes it cheaper.
The shafts of the driving drum and shaft are connected directly; slave arrange free rotation, placing it on the bearings.
Pulleys for a home-made belt-type grinding machine can be made of square billets from chipboard. Central holes are drilled in them, combined, gluing, to a thickness of 24 cm. Then the bag is pierced, giving it a cylindrical surface with a diameter of 20 cm. In this case, the central part of the pulleys is convex, increasing the diameter by 2 ... 3 mm when grooving.
The latter will allow the tape to stay exactly on the pulleys and not slide off them. The slippage of the tape is eliminated by winding a layer of thin rubber onto the surface of the driving drum.
A sanding belt is made of a width of 20 cm from a sheet of sandpaper. Stripes are cut from the latter and glued back to back to the required length.