Spool holder for free-standing metal shelves

My farm is on free-standing metal shelves like these: https://www.walmart.com/ip/Hart-48-Wx24-Dx72-H-5-Wire-Shelves-Heavy-Duty-Steel-Shelving-Unit-4000lb-Capacity-Black/330694191.  

I designed this spool holder to attach to the front of the thin metal shelf side.  It has a sliding jaw that lets you clamp it down with an M3 bolt and nut.  I adjusted the design recently to make the clamping jaw a separate piece that could be replaced without having to reprint the entire arm.

The shelf hook portion should be printed on its side so that it has the strength it needs which requires a tiny bit of support which can be seen in the PrusaSlicer 3MF file.

Insert an M3 nut in the shelf hook part, then use an M3 bolt to allow you to tighten the clamp.

UPDATE May 2024:

I added a channel in the shelf hook that the arm sits in, which does a better job at preventing the arm twisting from the weight of the spool.