The pivots still needed holes in them. I could do this on the drill press, but the lathe is more accurate. It does take a while to dial the part in to center though.
There were two parts to tap (create threads in). This is where I discovered that cheap tap & die sets (purchased pretty much anywhere retail) are for cleaning up damaged threads only. Using them to create threads where there were no threads before is merely an exercise in frustration. I destroyed both of my tap handles, utterly destroyed one die, and boogered up one tap by ultimately using Vice Grips on it. Ugh. But I got it done. I will have to buy real "machinists" taps and dies online if I want to do this again.
I also got the hardware (including the spring, did you know Ace sells springs?) and bolted it all together. The result?
Well, it knurls. Unfortunately, because my drill wandered when I drilled the stack of 4 arms all at once, one knurling wheel is slanted so I get an incomplete impression on one side. Bummer. I have to decide now if I want to remake just that arm or do it all from scratch again using real steel and a further modified plan.