Yes, that BNC T-wrench on ebay is yet another form of installer. I have two different kinds from long ago, both commercial tools, but I have no ID or source info. One is made just like a nut driver, but the business end is a hollow cylinder with slots, that fits the outside. The other is a strange looking socket that has the same type features, but is made to go on a 1/4" square driver. I also built one way back, before I acquired the "real" ones. I took a male cable-end type BNC, and soldered it into a stubby-handled nut driver, in such a way that the outer ring was locked to the core. The original driver tip was whatever hex size that the BNC end fit closely enough to solder in. In use, it just goes on the female BNC as if it was a cable, but allows holding the position or slight torquing for installation, then unplugs just like a cable.
Be aware when using these things, that the BNC bayonet pins are not very strong, and will easily deform or even shear off if over-torqued. The real compression force and torque for installation should be applied to the nut in the back, while the tool just keeps it from rotating out of the desired pin position in the early tightening phase.
Ed
