Restricting Rotation in a Cylindrical Joint

Recently, I was showing a class how to constrain an assembly using the Joint command.  For this example, I was using a cylinder subassembly.  Typically, the piston will spin when using a Cylindrical joint.  When I was showing this to may class, I began to think of how some simulation software packages allow use to lock degrees of freedom in joints.

While looking at the options for the cylindrical joint, I noticed that I could not lock the degree of freedom, but I could apply limits.  My first thought was to apply 0 deg for Start, Current, and End values.  When I did this, I was still able to spin the part.  Then I realized this would be a good application of the "Almost 0 Factor."  I use .001 as a value to represent almost 0 in Inventor, I call it the "Almost 0 Factor."  I will write a blog about the "Almost 0 Factor" some day soon.  When I applied .001 deg as the end value, I got the part to slide, and only rotate a small about.  The small amount of rotation was acceptable because you will never notice the rotation.

Here is a Screencast I made that demonstrates the process and outcome.

Thanks for reading,

Steve