Kip, got two 6' lengths of about 8DP rack, no pinions that's only suitable for a gate or similar you can have.

BTW saw a gate mechanism, home made that used one of those motorised liner ballscrew assemblies. He'd mounted the fixed point behind the pivot point in X and Y to be technical so it had a mechanical advantage and the 10" or so travel was enough to swing a big 5 bared gate.