Not quite coplanar anymore

[franquin]

I can work around this, but Id like not to have to do so every time this arises…
After a few operations on the inside surface, the outer rim shows subtle triangular patterns. This happens in the upper and lower outer quadrants of the wheel, exactly 90 degrees each, at a 45-degree angle.
I’ve repaired the damage through substitution with an early, untainted version, only to see the patterns re-emerge after resuming work. For now, the solution’ll be to make the substitution last, as this has proven to work.
It should be noted that the distortions aren’t structural, per say; None of these show up when toggling the “Show/Hide Geometry” button.
But I’d like to know if and how this can be avoided, specially since it might give me an insight into similar problems I keep encountering.
As usual, thanx…

lens mount.skp (2.7 MB)

[Wo3Dan]

I can’ t download your model to see it (it’s alright), but I’ll bet it has to do with the size of the wheel.
What happens if the scale definition is held by an instance that is 10x or even 100x the size you actually need?
(@DaveR might call it the Dave method).

Copy the wheel component that has no issues.
Scale one instance up 100x.
Right click on it and select ‘Scale Definition’.
Make changes only in the larger instance that holds the ‘Scale’ definition. The smaller one follows the changes without vettices that may jump to different locations.

[franquin]

That could be it, since I sometimes revert from 1000x to life-size when working with direct measurements. Some operations can be made before I go back to large-scale.The next project, if any, I’ll use millimetres, no problem with unwieldy conversions then.
If only the app wouldn’t show feet and inches when your inputs are in 1000’s of /16th’s, I wouldn’t have to go metric.