You can buy ready-made touch testers, or you can make them out of simple materials. Aim for points that are precise but not sharp. We like to use sets of 4 testers: a one-point tester, and two-point testers at 5, 15, and 30 mm apart.
Here are some ideas for DIY touch testers.
Tape toothpicks to an index card or a square piece of cardboard so that the points stick out past the edge. You may want to break the toothpicks in half. Make a different tester on each edge and label each one.
Unbend and re-bend paper clips so that their ends are separated by the specified distances. Larger sizes of paperclips are easier to work with. Pliers may make the bending easier.
Stick sewing pins into the sides and/or ends of a cork or a rubber stopper at the specified distances. For better precision, use pins with small heads.
