I have a first run of a couple of the v3 parts resized for imperial, but before pushing them up I want to put this out for discussion. Below is the axis_spacer_collar. Imperial 1" PVC is slightly bigger than the metric PVC this is sized for, and I’m using the exact same bearing as v3 was designed with. This leaves us with just .4mm between the outer PVC wall and inner bearing wall on each side. Given that my nozzle diameter is .4mm the slicer had a bit of an issue, and instead of a thin solid ring I have a perforated ring.
Now, for installation this works out to be a bit easier as you can slide the base of the collar on to the PVC, and the perforated ring squeezes a bit to fit into the bearing which can then slide down to a snug fit.
It ends up being a perfectly tight fit, with some force I can move the combination up and down the PVC pipe so the mounting screws will be fine holding it in place. The bearing handles all movement in twisting. The only down side is that a couple of the ring pieces did break off when mounting, and I imagine they may break off from the base through use. However, they are so tight between the PVC and the bearing that they would still serve their purpose as spacer if they did break away.
The one down side to this that I can come up with is that, being such a tight fit, the bearing installation would then be permanent. Any type of dis-assembly for portable use would break the spacer collar. Personally, I don’t see a problem with this but if someone else does then we may want to look at a bearing with a larger ID to accomidate imperial PVC.
(edit: tagging @Paul_NA8E for his thoughts)