Regrinding a Hardened Dividing Head Worm Screw

The worm screw in my trusty Walter UTA 100E dividing head was damaged by corrosion, which I didn’t notice until I recently checked it’s indexing accuracy. This worm is dead hard and the corrosion quite deep, so reconditioning is probably only possible by grinding. However, grinding that worm screw is not as straight forward as cutting threads on the lathe. So I came up with a grinding setup that borrows some parts of my Deckel D-bit grinder. This setup is used on my EMCO V13 lathe. Also I had to figure out particular angles and the necessary lead screw gearing ratio, avoiding rare gears which I don’t have. The reconditioned worm is now probably as good as new and ready for another 50 years of service!