Fixture on cast pads, not cast walls

Adding three small pads to the casting whose only job is to be clamped on. Repeatability across the bolt circle improved immediately.

Clamping on the housing wall. The wall flexes about 0.1mm under clamp and springs back after machining.

Cheap to add at the model stage, impossible to add later. Worth asking on every quote whether the part has somewhere to be held.