CNC Turned Parts - Sticky Pin Method
An alternative, the sticky pin method, is especially suited to locomotive wheels or flywheels. An ordinary house- hold pin is mounted in plasticine or Blu-tack, perhaps stuck on the lathe tool, and is arranged to point to the in- side diameter of the wheel or flywheel, the area that is not machined but is left as cast. Adjust the casting until the unmachined face is running as true as you can get it and the wheel is ready to turn. The sticky pin method is also useful for setting up work that has a chucking spigot, such as a locomotive smokebox door. Just hold the chuck- ing spigot in the four-jaw chuck and adjust the casting until it runs true on the outside diameter and the front face.
Using a commercial sticky pin to set work true. The methods of centring work in the four-jaw chuck that have been discussed are also suitable for setting work true on the faceplate. The next chapter looks at turning between centres and using the faceplate.
