External references question

Hi,

I have a quick question regarding external references andin-context design.

I have a model of a hollow cylinder of a certain, changeableinternal diameter, and this is the first component created in atop-down assembly.

I would now like to create a solid round shaft that will eventuallybe placed concentric to the hollow cylinder but needs to be able tomove along the axis of the cylinder. The solid shaft needs to havea diameter that is always 1mm less than the internal diameter ofthe hollow cylinder, whatever that internal diameter may be.

The problem I have is that when I reference the diameter of thesolid shaft to the internal diameter of the cylinder, an InPlacemate is created and it is not allowing me to move (translate) theshaft along the axis of the cylinder, which I need to be able to dofor a Motion Analysis I plan to run later on.

If I delete the InPlace mate the external reference to the internaldiameter of the cylinder is broken.

Basically I need associativity between the diameter of the shaftand the internal diameter of the cylinder, but I still need to beable to move the shaft around in the assembly.

What would be the best way to achieve this? I have tried usingEquations but when I am editing the shaft sketch I am not able toselect the internal diameter of the cylinder to use in an equation.

Any help is appreciated.

EdmondSolidworksAssemblies