CHAPTER 20 ■ COUPLERAlthough this tool cuts very straight, the ends of soft tubing curl in slightly after being cut. With this
reduced diameter on the ends, the tubes no longer fit inside of each other. You can sand the curled ends
down or core them out, but it isn’t worth all the effort.
Variable-Speed Rotary Tool
A variable-speed rotary tool is like an extremely fast power drill (see Figure 20-9). But instead of only making
holes, you can add various discs and attachments to sand, carve, route, and cut.
Figure 20-9. Dremel variable-speed rotary tool with cut-off wheel accessory
Figure 20-8. Mini tube cutter
■ Caution Always wear a dust mask and safety glasses when operating a rotary tool. I can’t tell you how
many times the thin cut-off wheel has shattered and flown in all directions.
Variable-speed rotary tools are available at most hardware stores. The tool runs from $35 up to $200
depending on the features and included accessories. Dremel manufactures the most popular brand. There’s
nothing wrong with starting with the least-expensive model, although a mid-price kit is a better investment.
In robotics, a variable-speed rotary tool is as irreplaceable for bodywork as a multimeter is for
electronics. It is worth obtaining and practicing with this valuable tool.
Securing the Tubing in a Vise
A vise consists of a pair of heavy metal blocks, called jaws, connected via a screw (see Figure 20-10). Turning
the screw handle causes the jaws to come together, clamping the material in between. This firmly holds the
piece on which you’re working.