Runout vs coaxiality

[[Da...]]

Hi all,

Can someone explain what is the difference between radial runout and coaxiality ?

I need to check runout of cone to cylinder however our different measuring machine show different reading compared to what I have on a CMM and when I do coaxiality is much similiar.

[[Da...]]

Coaxiality checks a feature's axis to a datum. Run-out checks this feature to the same datum, but it mimics the measurement with a gauge dial touching the surface. It will take into account all the deviations of the surface and the concentricity at this level at the same time. If you check the whole axis, this is called total run-out. It's as if you use the gauge dial to check the surface of the whole feature while moving the dial up and down the entire axis.

Total run-out catches everything about the deviations of a single feature. You can break it down into cylindricity and coaxiality, and the simple run-out can be broken down to roundness and concentricity.

[[Da...]]

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Here I think is explained well -> https://www.youtube.com/watch?v=NArW09DFhf8

[[Je...]]

Here is Zeiss's GD&T definitions poster:

Zeiss_Poster_GD&T.pdf

[[Ow...]]

If using Coaxiality, be sure to have additional report and axis end points turned on the characteristics settings editor. With them turned on, it will show the coordinate (XY?) positions for each scan and help you determine how the cone is out of location at them coordinate positions.
Everybody probably knows to have axis end points with true positions turned on but, not everybody knows you can use it on Coaxiality too.

[[Da...]]

Run out and coaxiality don't work very well on cones. We tried to get correlation to several different methods and it doesn't seem to work. Especially if its a steep cone. Anything over about ten degrees and the numbers don't work too well.