The flywheels were turned in the 4-jaw chuck. Rough alingment was made using the hub as a reference. First, half the flywheel rim was rough turned, allowing stock for removal on the final cut. The hub was also turned and bored, and faced to the correct width for that side..
The scribe was made from a piece of TIG welding rod, sharpened to a point. It is held in the toolpost, and centered to the flywheel hub