sissy bar?
"A five foot long section of 9/16" square bar stock bent at the middle and 15" from each end. Last 15" of each end should be parallel, and are spaced 8 1/2" apart, measured center to center."
From top to bottom the bar is about 27" tall. They only had 5/8" stock, so I went with that and ground the ends to 9/16". Fits tight in the plate sockets (which are not exactly square by the way) Once I had that piece made, I used the side plates to mark the location for four holes to mount. I drilled the holes on a press from the outside in, then used a tap set to thread them. I painted the whole thing with one light coat of flat black, then mounted the side plates using allen head screws with lock washers. Then I masked the side plates and shot the entire bar with multiple coats of Rustoleum truck bed liner. It is an exact match to the wrinkle black on my Street Bob.
A few weeks later I drew a maltese cross on card stock, cut it out, and took it to another shop with a laser cutter. Had a guy cut a piece of 3/16" flat stock into the cross shape. It fit between the bars, and I welded it in there at four points.
The whole thing is very heavy and solid. It would work better on bolted side plates. The detachables have to be tight, or it will rattle a little. Without the center piece you could flex the ends less than a half inch when it was not mounted. With the center piece bracing it, it is totally stiff.
https://www.denniskirk.com/cycle-vis...ck.p493832.prd



