The knobs look like a non issue, but the u-channels in the link are't "closed" like the ones in the pic. I'm assuming a threaded bolt is slid into the channel and the top being closed over the head of the bolt but wide enough for the threads of the bolt to catch a knob/nut is what "locks" a plate into place.
I would need a u-channel that isn't completely open on top.
Thanks for the leads.
******* UPDATE - looks like they are called c-channels or box channels ********
Last edited by drkphibr; 12-05-2012 at 4:12 PM..