Spent some time cleaning up the angle iron with a sanding wheel and wire brush using my angle grinder. Match drilled each of the two 5' hinges to the bottom plate and bending plate using a 3/16" cobalt drill. The hole spacing is 4" (64 total) and they are staggered high-low for torsional load distribution. I noted that other builders of this brake removed the hinge pin and drilled each half separately but - unless I'm missing something - I have not yet found this necessary. Punched matching dimples to each hinge-half and it's mating brake plate to ensure I don't waste time trying to figure out what goes where when it's time to reassemble all the parts after deburring, cleaning and priming.