Reworking my Belt Grinder


This week a problem with my belt grinder popped up so I had to deal with it. Specifically, when it was running full-speed, the whole thing was vibrating a lot and the ball bearings were very strained and got ruined relatively soon.

This was due to the wheels being just 30 mm in diameter and the driving wheel on the motor not being completely concentric with its rotation axis. I cannot afford to buy a new set o of pre-made tracking wheels and a new driving wheel for the motor; thus I have spent a week repairing and improving what I have. That is one advantage of DIY machinery – I can repair or change it whenever and however I want.

I increased the tracking wheels from 30 to circa 60 mm by wrapping them with canvas soaked in epoxy, thus essentially coating them with a thick layer of micarta. The resulting wheels were slightly bumpy and oval. For the motor wheel, 5 mm micarta was enough. In the end, I ground and turned all the wheels down so the surface is concentric with their rotational axis.

Unfortunately, I do not have a recent "before" picture, but that is not a problem because the aluminum cores are visible and they represent de-facto the original wheels. Doubling the wheel diameter halves the rotation (and the strain) of the ball bearings. Improved concentricity of the motor wheel has significantly reduced belt vibrations.

And since I have started re-building the belt grinder, I have decided to improve the platen behind the belt too. But I can finish that next week because I had to order some material that I, unfortunately, did not have in my scrap pile.