Horseman part

I picked up an 8x10 "project" camera from Midwest a couple of months
ago.
It was constructed from some Toyo and Horseman parts, coupled with some
quality picture frame components. It's actually rather well-built.
I've finished most of the project but now have one last thing -- tripod
mounting.
I can either have the short (half-meter) monorail tapped at a machine
shop so
that it will screw directly onto a tripod, or get the Horseman mount
part to do it right.
(will provide pic as needed).
Anyone know of a source for the mount part?

TIA,

Collin