ClipArt ETC
"This attachment, which may be readily affixed to any lathe, consists of a lever that is attached to a crank shaft, which latter has its bearings on the slide rest. From the crank there is a connecting rod which goes to the slide rest. By means of the lever the rest can be moved to and fro on condition that it is free from the cross feed." —Grimshaw

Cam Turning Attachment for Lathe

"This attachment, which may be readily affixed to any lathe, consists of a lever that is attached to…