I need to find a particlur type of connector

[rampartc]

8. i'm tempted to say that looks like a chicago screw

IF that hole is 3/16" or larger that might be the first thing i'd try. they come in varying lengths and the cheapest/easiest to procure are at the office depot. different finishes and materials are available but that 3/16" diameter is constant.

https://www.binding101.com/binding/binding-supplies/screw-posts?msclkid=a2c2c71cba5716ab08daa737a319ab21&utm_source=bing&utm_medium=cpc&utm_campaign=NX_NTM_Search_Binding%20Supplies%20(L)&utm_term=chicago%20binding%20screws&utm_content=Screw%20Posts%20-%20Aluminum

carriage bolts come in every diameter and length at your local hardware store. some thread might show between horses but that could be covered by running through tubing stock or even heat shrink tube.

sort of puts me in mind of a "20 mule team" model i had as a kid.