There is no shortage of people on the internet that bash on Harbor Freight tools. I myself have picked up some losers there, however, I've also picked up a lot of things that just work perfectly from Harbor Freight and this is one of them.

This Bauer Surface Conditioning tool has been popping up in comments from people in my metal and plasma working groups and I just had to give it a go.

Its available at Harbor Freight of course but it's also available from Amazon for the same instore price as Harbor Freight. Here's the affiliate link( https://amzn.to/44W3vfr ).

The BAUER™ 9 Amp Surface Conditioning Tool delivers up to 3700 RPM for removing rust, paint, and conditioning metal surfaces. Built with a front Dhandle for maximum comfort and control and lockon trigger for extended use. Accepts a wide variety of 4 in. x 4 in. sanding drums.

Here's the specs from the Harbor Freight web site.

Variable speed control delivers 10003700 RPM for surface preparation applications
High torque 9 Amp motor handles the toughest jobs
All metal gearing for long life and durability
Six speed control dial to match sanding speed to application
Ergonomic inline design reduces fatigue during extended use
Accepts a wide variety of sanding drum accessories
Drum guard keeps debris away from user