How to accurately measure pitch of serrations

I need to accurately measure the pitch of some serrations on a flat surface (ie not a splined shaft etc) - so I can make up a matching serrated part for an adjustable clamping setup.
My first thought was they might be a standard thread pitch so tried to find a match with pitch gauges but no. Pitch falls in between 1.0mm and 1.25mm

I’ve measured across 9 serrations with digital calipers and get approx 10.38mm - which makes it ~1.1533..mm pitch.
Obviously the more serrations you can measure across the more accurate your pitch will work out.
In this case I only have the 9 serrations.

For this application 1.15mm will be fine - but it got me thinking as to how else you could measure the pitch?
Normal calipers aren’t the greatest for determining the middle of the grooves. Something with equal angles on its measuring points would be better.

Is there a special instrument or technique to measure serrations?

Steve


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