...I presume you are not a machinist by trade?
Nope. Mechanic. I'm using a little hobby mill, Harbor Freight job. It works, but it can be aggravating. Chuck walks, table wobbles-these things have to be accounted for when doing final precision cuts. Always swipe one direction, preload the table with my hand and gently turn the dials, etc. Quality bits help, but the mill is just not great. I'll get a bigger, nicer one when I have room, but as of now, this little bench top is about all I have space for.
Got the other caliper done tonight. Still need to build a brace to go across the top, though, since each one is only held to the diff with one 8-32 screw. Not going anywhere, but not as solid as I'd like them to be for the speeds I expect to run. We'll see if the 180 oz servos can pull the cables hard enough to stop this car, too. I expect curb weight to be about 6 lbs. The way I profiled the brake cams, they don't need to travel far, so I should be able to attach them on the innermost servo arm hole and get max leverage.