I designed this part to hold my amp stand securely to a dolly made from 1x3 pine and a $5 set of casters from Menards. This piece fits over a 1x3 end, and screws are used to hold the caster and the printed part to the 1x3. Many pipe style instrument stands have a rubber sleeve for grip to the floor or whatever is placed on them. These pieces I made kind of grab on to them to hold securely in place. One would use 3 of these. The result, for me, is a secure and stable dolly for my Gator amp stand, which holds a somewhat heavy amplifier (in this case, a Line 6 Powercab 212+) It is very solid and would take a lot of effort to tip it over.

This is a niche model for certain, but I am posting in case anyone wants to put their instrument stand on wheels, as I have.

The casters I used are Performax 2" casters, sold as a package of 4 at Menards for $4.99 retail, but many other 2"  casters have the same bolt pattern. 1x3 pine is cheap for a 6' piece. I glued and screw the pine cross members with 1½" wood screws, and 1" metal screws to hold the casters and parts to the pine. I painted the pine frame black before adding the hardware.

Printed in PLA on a Bambu Lab P2S with no supports and 15% cubic infill with a color change from black to grey on layer 26, just for cosmetic value. PETG would be fine too, and it could be printed on almost any printer with no supports, as the max overhang is only 45 degrees. I printed all 4 at once in just over 6 hours, and built the frame and painted while the print was running. 10 minutes of assembly after.

Also, see cable clip solution for stands here: