Page 76 - Making things move_ DIY mechanisms for inventors, hobbyists, and artists

Chapter 3 Screw It or Glue It: Fastening and Joining Parts 57

P roject 3-1: Drill and Tap a Hole

As an example, let’s drill and tap a piece of aluminum for a 4-40 screw.

Shopping List:

• Scrap piece of aluminum
• Clamp (like McMaster 5031A6) that is wide enough to fit your scrap
aluminum piece and worktable

• Center punch or other hard, sharp, pointed object
• 4-40 screw (any length and head style will do)
• Small tap handle (McMaster 25605A63)

• 4-40 tap (one that is designed to fit into the tap handle)

TIP The chamfer is the tapered part at the front of the tap that helps guide
the tap into the hole. Choose a taper chamfer (McMaster 25995A125) versus
a plug or bottoming chamfer if you have the choice, because they are easier
to start.

• Tapping fluid or WD-40
• 0.089 in diameter drill bit, also known as wire gauge size 43 according to
Table 3-1 (any good drill bit set should have this size, or you can buy it
individually, and choose the standard jobber’s length if you have a choice;
McMaster 30585A57).
• Drill (any hand drill will do, cordless or otherwise)
• Small rounded file or countersink tool (like McMaster 2742A26)
• Safety glasses

Recipe:

1. Put on your safety glasses and clear your workspace.