I have seen a few versions of this sort of thing. I was about to toss out some scrap from an old RTA stereo cabinet that I had already cannibalized for my spindle sander risers. I thought before I committed the scrap to the land fill, I would try a mock-up of a ROS table to see if one could earn its space consumption in my shop. The idea here is to give you a ROS action at a predictable angle for working small or irregular parts.
I keep some threaded rod around and had scavenged inserts and so forth from other items prior to sending them to their eventual resting place . . . somewhere, anywhere out of my shop . My version will clamp in a vise but I have seen versions on skids that clamp to the bench via hold downs. I was interested in making it as small as I could while still keeping it useful.
There was a period of time when Klingspor's Woodworking Shop was selling re-badged Bosch tools at a reasonable price. They got out of this line and clearanced a bunch of stuff. I love my Bosch 1295VS (discontinued) so I grabbed one of Klingspor's versions. That was years ago and I think it may find a home in this jig. The table is adjustable forward and back to allow easier paper changes. I need to be cautious when tightening things down to assure that I don't accidentally crush the sander body .
I have a foot pedal that I keep near the bench and use for router mortising and other frequent on/off tasks. It triggers a vac so the sander and vac work in concert. In the second to last picture I have already sanded all the pulls you see in the last picture. Dust collection seems to be surprisingly good .
It took me just bit longer to make the jig than I would have spent sanding these pulls by hand. I can already see that this is a keeper. There is some additional bracing that I will add to better support the table arms and after running it for awhile, I may make a version 2 out of something other than an old stereo cabinet .