Mostly Universal Carriage- 3/8" rods, integrated bearings

A basic thing I did late one evening, it's not too elegant- but it should do the job economically.
I started out with making a design that didn't use bronze sleeve bearings, or any metal pieces other than M3 screws and nuts. Then I realized I had no idea what it had to fit.
That's when I fell back on the old grid.
Grid spacing id 5mm. Why not.
May take a bit of filing to get the width exactly how you want it, but it's late at night and hobbyists can manage.