Hi, this sort of thing is very easy to make,


These are widely available on the net but are not cheap. Make your own in under an hour for next to nothing. Part A is the fixed part, the threaded rods would be held in place by nuts. Part B will move along the horizontal rods and when done up will hold the fellas in place. Part C is the clamp that moves up and down along the vertical rods. You can use extra nuts between A & B as spacers. Piece of cake.
J