I bought an older Presentation 3000 vise. I’ve cleaned, lubed and got it nice. However, I think it’s set-up right handed and I’m not.
At the end of the shaft it has two knurled knobs with a brass handle between them. When rotating the shaft clockwise the brass moves the shaft, but when you move CCW the shaft doesn’t turn. Similar to a rachet for a socket.
If it’s like my 4000, take off the Phillips screw on the back, take off the knurled section the Phillips screwed in to then slide off the handle used for rotating the head. Inset in that handle is a one-way bearing. Reverse the handle, reassemble and then you’re good to go.
You could also call Renzetti. They have been VERY helpfu with questions I’ve had over the years.