In the drafting stage, I create basic shapes with boxes
and circles. The shapes will be used in the Tool Path
Creation stage to create the tool paths. For most of my
basic part making, I use a 2D CAD program called
CorelDraw. While I will be using CorelDraw in the next few
examples, you can easily use other software packages.
Most of the concepts I use will have counterparts in your
software. Adobe Illustrator is another software package
that is suited to this process. The most important
consideration in choosing your drafting software is its ability
to export an accurate file format your CAM software can
Drafting — Step A
I start by adding the shape that represents the stock I
am going to use. In this case, it is the blank side of a 1” x
2” domino shown in Figure 4. I used calipers to get the
exact width and height of the domino. The closer your
drawing values are to the actual size of the stock, the more
accurate your pockets and holes will be in reference to its
edges. This is especially important if you are mating two
parts and want the edges to line up.
Note that I have included the dimensions in the figures
shown here. This is only for illustration purposes. I would
normally not include dimensions in the drawings to be
exported to my CAM software. The dimensions would be
interpreted as part of the drawing and could make it
difficult to line up the stock later.
Drafting — Step B
Next, I add the pockets to the stock. Here, I have
added the place where I want the main pocket in the
bottom domino. To do this, I added a rectangle of 1.75” x
. 75” to the center of the stock as shown in Figure 5. I also
added a 1/8” fillet to each corner.
It is important that your inside cuts are not any sharper
than the radius of your bit. If they are too sharp, your
drafting representation will not match what is machined.
The ability to center one object inside another will
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Figure 2. Figure 3.
Figure 4. Figure 5.