Nuts & Volts - July 2004

Personal Robotics

is really a must. I personally do not have a bench vise, but my little Panavise does everything I need. Remember that the jaws of a vise can mar softer materials.

gradations can be used to fit contoured sections. This is the staple of my construction and I always keep some around.

Small tweezers: These are really useful for picking up and positioning anything that is smaller than the distance between the tip of your index finger and thumb when pressed together. Here is another area where I don’t skimp; a crappy set of tweezers is more of a frustration than anything else. I have had a set of tweezers from Grobet for about a decade and they continue to serve well.

Polystyrene sheet, 0.040” thick: Use this for round shapes or small pieces. Other thicknesses are handy, as well, to make spacers and cosmetic features and for areas where stronger assemblies are required.

Wire cutters and strippers: Wire cutters are a must for electrical work and strippers are really, really handy. Again, for precision hand tools, I do not skimp. A word of caution is in order though: do not use wire cutters for cutting anything other than soft materials. Steel music wire will ruin them. My brand of choice is Xcelite, although I do keep a cheap pair or two around to custom shape on a bench grinder.

Plastruct shapes, like “L” beams and square sections: These can be made to build mounts for servos, as well as other structural components. Use the thick-walled, gray stuff. I personally like the 1/4”, 3/8”, and 1/2” square tubes best. I use them to make structural shapes that I attach other components to. The thick-walled stuff is more robust and you can actually use self-tapping screws.

That is it for basic tools. While there are many different tools here, you can keep things to a minimum. You don’t need to buy every metric, fractional, letter, and decimal drill, for instance, nor do you need to buy every file shape you can imagine. Don’t be lured into really cheap tools and don’t feel compelled to buy one of everything where there is a variety.

As far as materials are concerned, consider the following:

Double-sided tape: Your local hobby store should have some thin rolls of servo tape available. This is excellent for — well, you guessed it — servos. It is also handy for mounting subassemblies as well, provided that you have a large surface area. I will sometimes build a 1” x 1” flat area onto a subassembly, like a sensor platform that can be double-sided taped to other parts of the robot with similarly large areas. In this way, I can experiment with a variety of sensors without the hassle of fasteners.

Mechanical components that will cause stress — like motors or servos — may not lend themselves to this method, though.

Wire Cutter and Stripper

Evergreen scale models “ sidewalk”:This is basically a polystyrene sheet that is pre-scribed in a ruled pattern. This allows you to snap off pre-measured square or rectangular sections and provides an accurate ruling to place other components.