I tried fitting the eccentrically drilled bushes in the upper wheel clevis after I welded it up on the weekend and found that there was a tiny bit of play in them, so tonight at tafe, I align-bored the clevis and machined up two new bushes. I haven’t drilled the eccentric holes yet- will do next week.
I’m still not too flash at using telescopic gauges to measure bores, but from what I could measure, there’s about 0.05mm clearance. No noticeable play, and they only slide in if you push them dead straight.
Machining protip: Brass is super soft and easy to cut, but that doesn’t mean you should ever be lazy about cutting it, especially when parting off. When parting off, cut in about 10mm, then back off, move across a half-partoff-tool width and cut in again so that you have a generous amount of clearance around the tool when you start to get deep. Even with a carbide cutter. When soft materials grab, they GRAB! On a related note, the best way to bend a parting off tool holder is by putting it in the vice with three thin metal shims in a kind of a seesaw arrangement…