The Vertical Lathe
When we say a vertical lathe, what we mean is a lathe that has its vertical axis placed at the bottom of the machine, and the legs of the vertical shaft are carried by the horizontal support. The poles of the legs of the horizontal shaft must be tightly coupled together to avoid the sliding of the shaft on the vertical axis.
It is also possible to construct a horizontal shaft with a vertical angle between ninety-five and one hundred and forty degrees. Although these angles are not usually allowed by machinery manufacturers, as they are regarded as too narrow, construction of the shaft with a ninety-five degree angle has proven to be a very successful way of producing high speed production tools.
The tripod consists of a crosspiece which supports the vertical axis and the taper which guides the turning motion of the cutting tool. The horizontal movement of the crosspiece is governed by the horizontal pole located above the hole and held by the diagonal links. A shorter crosspiece would work in the same way but would take longer to turn, while a longer crosspiece would work faster.
The axis of the vertical axis should be free from any obstructions when it is about to be turned. This is done by drilling out the bolt hole, or the adjusting nut on the tripod, and then turning the axis on the drill. If you cannot reach this area, there are several good tool holders available for this purpose. It is best to hold the handle for a few moments until the drill whirls around and unblocks the bolt hole.
The horizontal axis can also be moved horizontally, as you would normally do on a lathe with a horizontal axis. This should be done without disturbing the vertical axis and is done by using a small but precise guide which is attached to the horizontal axis and moves along it. Turning of the axis and then attaching the guide provides an uninterrupted movement.
In lathes that have a slightly off center cutting surface, it is possible to mount a screw gun in its place. It is a good idea to consult a lathe master before doing this as there are a number of screws that need to be lined up in order to use a screw gun effectively. The screws should all be tightened together before they are screwed into the screw guns in the machine.
A number of screw guns can be mounted to a single machine, and if this is done properly, a more accurate turn can be achieved by means of a manual pulley system. By holding the support wire with your thumb and forefinger, the machine’s axis is turned to the right or left.
Once the machine is turned correctly, the wires are pulled taut and the axis is put back in position. Then the axis is again aligned.