I have finally got this SXII in my posession. we are in the process of hooking it up and there is a air line that runs to the bottom of the knee that isn't attached to anything. The previous owner never used it but thinks it was used to move the knee up and down. I also need copies of whatever manuals are out there if there is a source for them. :confused:

Maybe the air was to a counterbalance cylinder?

Excello mills used a air cyclinder either side of the knee for as HU said for counterbalance when operating the power knee (used for initial positioning only).
The air regul;ator valve was a special constant pressure type to maintain pressure both dir.
Al.

The knee raising screw pedestal itself has an air cylinder in it. There should also be an air regulator for it. Mine leaks like crazy. My understanding is that it's pretty much essential if your knee is powered.

In case I wasn't clear, it works as a counterbalance.

I've also used contour tracer attachments for a mill where the knee is positioned by a controlled by a tracer that mounts on the head.

As the table moves in X-Y, the tracer contacts a pattern that is offset from the stock to be milled.

Ken