Measure position of thread

[[Wi...]]

Hello everyone,
does anyone in the community have experience with measuring the position of an internal thread.
As I said, you don't have to measure the thread parameters, just the position.
So far I have inserted a test pin into the internal thread and measured this test pin, which protrudes from the thread, as a cylinder. Now I want to measure directly, without this test pen.
I have already done tests, but the scatter when I directly measure the internal thread as a cylinder is relatively large for repeat measurements.

[[Ma...]]

I had quite stable results by measuring with self-centering and helix path matching thread pitch on Vast XT head.
But it mostly depend on previously made hole ( cylinder ). Threads are mostly made with taper, but some threads are made with inserted mill, so thread can be non coaxial.

Owen posted nice attachment viewtopic.php?p=910#p910

[[Wi...]]

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Because the taper, you are right, I have also this problem. But your solution, I will test, thanks.

[[Da...]]

Different people will tell you different things. My advice is to test out different strategies (single points or scanning, Gaussian or inner tangential, different point densities) and compare those to a thread plug and see what works best for you. Otherwise you will always be in doubt.