Thanks Josh,
The clamp is the Ram brand of mounts and holders. I also have a front ball mount with a Brass blade clamp I made for for flexible blades.
You can see photos in the Mods section sticky “Show Me your Mods”
The balls are 1″ with 3/8″ threads. the clamp riser was through drilled and tapped for the 3/8-16″ threads.
I have several length arms based on the knife lengths. The setup pictured is listed below and is rock solid!
Ram-B-201U-C 6″ Aluminum arm
Rap-B-379U 1″ Tough Ball with 3/8″-16 threaded Stud
Rap-B-400U Small tough Clamp with 1″ Ball Mount
This setup cost around $90.00 “your mileage may vary”
I have played with the mounts and found that the best setup for me was to clamp the knife as normal and adjust for equal vertical side angles on your blade.” ******NOTE*****some knives are not flat and will not be correct at a zero angle”
Leave the Ram Arm tension loose and tighten the Ram Clamp on the handle.
Snug up the Ram arm tension and recheck the blade angle then finish tightening the Ram Arm.