I needed to settle some concrete in a block wall I built, so I needed a concrete vibrator.
So with a piece of 25nb pipe, some threaded rod, and bits and pieces, I made one. It took about 2 hours to make, and easily saved twice that (and so much more effort) over manually agitating the concrete.
I did have some small dramas with the attachment of the cable to the the rod, but that was fixed with little hose clamps, and I need to take it apart again to get the shaft to spin more freely. I'm pretty sure the weight is catching on the bearing shim sheet metal.
Music from https://ampletunes.com/