Let's See Your Lathe

[PixMan]

The device on the back of the cross slide is (as far as I can tell) not a box turning tool but a Landis Company "geometric" type threader. They are robust and can cut a wide range of threads, though you need the thread chasers for each pitch. What I am not certain about is that most threading heads are mounted on a axial floating holder so it can "follow" the thread it's cutting. The lever with the round knob is the resetter. When you set it up there's a stop in the back that actuates the "spring open" feature as it reaches the set length of thread. The resetting lever "cocks" the chasers back into cutting position after each threading operation.