There are currently a lot of designs for c-beam, linear rail systems 56 and more universal clamps to fit a range of routers that can provide a more repeatable/durable solution but is more expensive. Free designs available on communitygarden 19 and for sale 55 The Maticulous Z-Axis 44 - Designed by MaticulousMaynard - Free design available on communitygarden 7 There is also a good idea to use a stepper motor instead of the DC gear motor.