CNC Mill Mark Removal in Intake Port

Newbomb Turk said
Rough is always better. That’s according to Darin Morgan and Larry Meaux.

The outlier is CNC step over. I’ve seen that so coarse you couldn’t even read the manometers.

I can’t remember what the CFM loss was but it was big.

I’ve never seen a burr finish do that but I would suppose it’s possible to get that too rough.
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Makes sense. I don't think CNC step-over lines count as 'roughness' so much since these can create a significant change in the cross sectional area depending on the size of the step-over and shape of the tool used. I'm surprised more ports aren't shaped with lay lines roughly parallel to the flow path.