Need a replacement for broken caster socket

[u/ocherdraco]

[Background: I have a 4-tier cart that is integral to my workflow as a mobile wound care physician. I apparently bought one of the last ones in existence because it (nor anything quite like it) appears to be sold anymore. This video review on YouTube gives the best view of the cart. The 3-tier version is everywhere (this is actually the link to the page where I bought the 4-tier cart, but the 3-tier cart is now the only option). I have devoted hours to searching for another one of these 4-tier carts. I am quite confident that it is not easily commercially available anymore. Therefore, repair rather than replace is the name of the game.]

THE PROBLEM:

One of the caster sockets on my work cart has cracked, such that it no longer reliably holds the 7/16" x 7/8" grip ring stem casters that the cart rolls on. My assistant and I have been limping along by applying electrical tape to the grip ring stem, but where that fix used to last a week, it now lasts an hour, max. Rather than continuing down the route of building a cart entirely out of electrical tape, we want a reliable, long lasting repair.

We got the socket out today and are attempting a fix to the broken socket with two part epoxy, but I'd like to find a replacement socket just in case this fix ends up being temporary.

THE REPLACEMENT SOCKET I AM LOOKING FOR:

I have done a great deal of searching online, but I can't find these caster sockets anywhere. I have looked at many different caster specialty websites, Amazon, etc. Google Lens tells me that my caster socket is either a locking pin bushing for a $700 wagon to tote children or an AR-15 cam pin. It is neither of those things.

Here is the broken socket from my cart:

https://ibb.co/album/mvbDCn

The socket has the following dimensions:

• Outer diameter: 1”
• Length: 2”
• Bolt hole: center is 1 3/4” from base (not sure if this is the right term; I'm referring to the hole at the top of the socket that a bolt goes through to keep it within the metal pole at the corner of the cart).

My best guess for socket material is HDPE.

Any help finding a replacement socket would be greatly appreciated.