Page 360 - Robot Builder's Bonanza

BUILD A 3- SERVO HEXAPOD 329

• 2 six- arm (“star”) servo hubs (they usually come with the servo)
• 1 large round servo hub (usually comes with the servo)

You need the following fasteners to complete the Hex3Bot (get extras in case you lose any
during construction):

4 3/8″ 3/8″ miniature L bracket, Keystone 633
8 #4 1/2″ sheet metal screws
18 4-40 1/2″ machine screws
8 4-40 7/16″ machine screws (okay to substitute 1/2″ length)
2 4- 40 7/16″ flathead machine screws (okay to substitute 1/2″-length pan head)
6 4-40 3/4″ machine screws
2 4-40 3/8″ machine screws
2 6-32 1- 1/2″ machine screws
2 #6 nylon washers (okay to substitute #6 metal washers)
8 #6 nylon spacer, 1/8″ thick (check the special parts drawers at the better hardware
stores, or you may substitute a stack of two or three nylon washers to build a spacer that
is a total of 1/4″ long)
6 #6 metal washers
6 #4 metal washers
2 6-32 locking nuts
10 4-40 locking nuts
24 4-40 hex nuts

Machine screws are pan or round head, unless otherwise noted.

CUT AND CONSTRUCT THE LEGS

G All holes are 1/8″ unless otherwise noted.

Begin by constructing the leg pieces; a cutting and drilling template is provided in Figure
27- 11. The four front and rear legs are composed of two pieces— upper and lower. The
middle legs have just one piece. The “feet” (bottoms) of all the leg pieces are cut at a 30°
angle. Use a protractor to mark the angle. It’s okay if it’s a degree or two off, but try to be as
accurate as possible to match all cuts.
Assemble the upper leg and lower leg pieces using #4 sheet metal (not wood) screws (see
Figure 27- 12). Using a pencil and the top leg as a template, mark the placement for the
mounting in the edge of the bottom leg. Prepare a pilot hole for the screw with a small 1/16″
bit. It doesn’t need to be a deep hole. Fasten the leg pieces using the sheet metal screws.
They’ll self- tap as you tighten them.
Notice that there are two styles of legs: the rear legs, which include a hub for connecting

27-chapter-27.indd 329 4/21/11 11:52 AM