When is an Axis, not an Axis ?

[shmbry]

When you are trying to use two axes to form a constraint.

Try constraining 'Y' of the 'Axis Test Sub Assembly' with the 'Test Axis' of the 'Axis Test Main Assembly'

 

[DavidJ]

Seems to relate to the way you created Test Axis - if you had used an offset plane from YZ plane, then created new axis from that plane and XY plane, your axis constraint behaves as expected.

Interestingly in your assembly, if Coincident 1 is suppressed, the Coaxial constraints on the axes seems to work.

I'm not clear why this is a problem - only have guesses at the moment.

 

[DavidJ]

Also works as expected if you placed the point by direct coordinate entry, rather than based on a sketch figure. So my suspicion falls on the sketch.