How to make a metal grinding machine

Hello, friends!

Today I’ll show you how I made this handy machine for cleaning metal — profile pipes, round tubes, angles, and other rusty or dirty parts.

It started with a three-phase electric motor, 2 kW, 3000 rpm, with a 22 mm shaft. I made a pendulum frame from 40×20 mm rectangular pipe, cut at 45° angles and welded into a single unit. Then I mounted the motor on this frame.

The motor sits on a pendulum, which allows adjusting its vertical position depending on the height of the workpiece. For the machine’s base, I cut four more pieces from the same pipe and assembled a frame — 550×400 mm. I also added two 45×45 mm angles to mount the rolling rollers below the brushes.

I turned five rollers and their bushings on my mini-lathe. The rollers are 120 mm wide. After drilling holes in the angles using a hand drill, I mounted everything onto the frame — both angles with rollers and the motor on the pendulum. I used bolts to keep the design disassemblable.

Next — the brush unit. I turned a shaft sleeve to match the motor shaft and the width of the brushes (125 mm). The brushes were installed in a stack with spacer rings between them, then tightened with a washer and bolt.

The first test run was successful — the machine worked with minimal vibration.

For the pendulum hinges, I turned four bushings and mounted them using a rear bicycle axle. I marked and drilled holes for the motor’s mounting legs, breaking a couple of drill bits in the process, but eventually got it done.

To adjust the pendulum height, I made a custom mechanism. It uses a stud with M12 thread and two custom-made parts: one threaded and one not. These are mounted to the lower and upper ears of the pendulum, allowing the motor to move up and down smoothly. I added a handle with a lock nut to prevent spontaneous rotation.

This mechanism turned out to be the most challenging part. It enables the brushes to lift high enough to clean even large parts. A lock nut was added later to stabilize it further.

Here’s the result — everything works great! I then added a protective cover and a start button. Remember to always wear safety glasses — wire bristles can fly in all directions.

To operate, I adjust the height, place a rusty pipe under the brushes, and lower them. The machine cleans effectively but should be used outdoors due to the amount of dust.

For convenience, I also added a phase switch near the start button to reverse the brush rotation.

In conclusion: this machine is a must-have for any metal workshop. It significantly simplifies cleaning metal from rust and dirt. I still use it five years later — and it works flawlessly.

Thanks for watching!
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