Cutting off rough stock freehand with my angle grinder was a pretty crooked affair, so I splurged $6.50 on an attachment from Harbor Freight. They call it a safety guard, I call it a fence. I was able to cut pieces for the new knurler straighter this time. Still not as nice as a bandsaw, but about $143.50 cheaper. Speaking of cheaper, I spent a whopping $2.28 on the steel (!) for this knurler. With prices like that for the good stuff, why would I ever buy Home Lowes metal again...
I scribed an "A" pair and a "B" pair of arms so they are drilled together (2 at a time, not 4 at a time) for the best possible alignment of holes. I also noticed in the picture that the original author had, after drilling one hole, put a bolt through that hole so subsequent holes would be as aligned as possible... something I'd neglected to do last time and won't forget this time.
Also to improve drilling accuracy, I sharpened my first drill bit today. Wasn't as dramatic as I would have thought, though it did take me three tries to get it looking somewhat like an unused bit. I drilled a test hole and noticed: 1. I didn't have to pull down on the drill press handle nearly as hard as I used to, 2. I got less of a raised lip of smushed metal around the top of the hole, and 3. I actually got a long continuous string of swarf instead of little chunks.
Drill bits have to be sharpened... who'd a thunk?!
I have high hopes for the rest of the build now.