screw cutting

Model B was next with power cross feed and manual gear change for screw cutting.

Screw cutting and welding facilities are also needed.

Model C had manual cross-feed and manual gear change for screw cutting.

Equipped for roll-crowning, screw cutting and copy turning.

The helical planing idea is similar to both helical milling and single-point screw cutting.

For screw cutting, a half nut is engaged to be driven by the leadscrew's thread; and for general power feed, a key engages with a keyway cut into the leadscrew to drive a pinion along a rack that is mounted along the lathe bed.