Z axis (saddle) servo motor bracket - CAD and CAM

Saddle drive (aka Z axis) concept:

Here's the tailstock end of the machine, with the ballscrew, bearing bracket, encoder scale and motor in position. The motor / pulley centres are at the correct length for the belt and pulleys I have now received from Bearing Boys.

With the driven pulley in place:

And the bracket I finished making yesterday. This allows the encoder to be mounted on the back of the bearing bracket.

...and also the plate that will mount the motor and allows +/-5mm of adjustment for the belt tensioning

Here's the model of the plate being CAMed up:

...and the toolpath

2D Chamfer toolpath problem:

The 2D Chamfer operation within Fusion 360 is a fiddle until you understand it. But even then, it seems to have evolved in recent days. Either way, it refuses to create a continuous chamfer around the oval slot, no matter what I do. This same toolpath was happy to run most edges I selected until a few days ago. Fuck nose what is going on. However, it's possible to use the 2D Contour operation instead - if you select the "chamfer" tick box. Here's what I mean, with the same oval chain selected.

2D  Chamfer:

2D  Contour:

Fair enough - 2D Contour it is then. 

Once I'd realised that the motor has a 50mm diameter register (rather than 45mm), I was able to finalise the model and get it machined.

Sorted.

Need to manually countersink the 2 fixings so they clear the back of the driven pulley. However, my 6mm chamfer won't manage it without a multistage operation, so it's far easier just to use a manual countersink tool.

This seems to work: