"On the two vertical sides of the block there are screwed on two flat pieces of steel, that have holes near their lower ends, in which the worm journals run. The worm and the worm—wheel gear with each other. The worm is turned by a small hand wheel." —Grimshaw, 1902

Lathe Turning Astragals

"On the two vertical sides of the block there are screwed on two flat pieces of steel, that have holes…