I wrote my own software that allows the user to visualize the appearance of the cuts in a 3D view. This software is available to others as the Computerized Ornamental Lathe (COrnLathe) package. This is the software that lets you design where you want to make cuts, what kind of rosettes to use, what kind of cutter to use, etc.

Having designed the cuts that you want to make, all that is needed is a means to generate the instructions to drive LinuxCNC. LinuxCNC is driven by a modified set of "g-code" instructions. No one ever wants to look at the actual g-code instructions (although you can, if you like). All you want is to have the design software generate the instructions and have LinuxCNC run the instructions.

The GCode Control Window is part of the software that controls some of the dynamics of cutting. Click on the photo in the left margin for a larger view of the window. It has 3 main modes of operation set by the icons in the upper left corner of the window:

• Cutting rosette patterns.
• Cutting a curved profile (that is, the outline of a shape).
• Cutting threads.

In all modes of operation, one wants to set the maximum rpm of the spindle during cutting and the maximum speed of the stage. These parameters are set in the Feed Rate Control panel of the screen.

When cutting rosette patterns, one wants to set the how deep to cut on each pass. Typically, you won't make a deep cut in just one pass. Then you also want to set the depth of the final cut. These parameters are set in the Coarse/Fine Cut Control panel.

When cutting the outline of a shape, one wants to set how far the tool is moved each time before the spindle rotates a revolution. Typically, you won't make a deep cut in just one pass, so there are controls to set how many course and fine cuts are to be made. These parameters are set in the Cut Curve Data panel.

When cutting threads, you need to specify the number of threads per inch, the number of starts, and the % engagement of the threads. It's also convenient to be able to calculate the required inside diameter and outside diameter of the mating pieces for the given threads you wish to cut. These parameters are set in the Threads panel.

Often, one will want to manually create a curved shape and then digitize that shape into the design software. This is easily accomplished by probing the surface of the shape and grabbing the coordinates with the "Probe" button in the lower left corner of the window. This is also useful for manually determining the desired location of a rosette cut.

The most important button on the screen is the "Write G-Code" button which creates a file on the stepper control computer that is running LinuxCNC. Then one simply runs the file on the LinuxCNC computer driving the stage.