I used threaded rod plastic tubing and Gibraltar rack clamps to mount everything. The tubing isn't working out all that good you can't tighten the clamp enough to allow tuning the roto by turning it. I'm going try something else just haven't decided what yet. Also built a wooden support for the bass to hold the pedal just a short piece of 4x4 and some plywood.
Have you tried a nut and washer on each side of the plastic tubing? Might work to lock the allthread in the tube.
