I need some suggestions how to build a jig to clamp pipe into for construction of gates using round pipe. We have some ideas but would like to get some input prior to us diving in to make one.

We are planning on making it about 20' long and 7' high and having it involve a number of vertical members that can be moved along the 20' length. the pipe could then be clamped horizontally to the verticals at what ever spot is needed for a particular gate size. It will work best if the jig or rack stands fairly upright and all of the members are adjustable in both horizontal and vertical directions.

I know that there are jigs like this out there, I've just never seen one. Any help would be appreciated!!