Paper mailing tube (telescoping - 1
inside tube and 1 outside tube)
Styrofoam trays (1 large
and 1 small)
Lenses (1 large and 1 small. See
note about lenses.)
Metric ruler
Razor blade knife
Cutting surface
Marker pen
Rubber cement
Fine grade sandpaper
Procedure:
1. Cut a short segment from the end of the outside tube. This circle will be used for tracing only. Place the circle from the larger tube on the large tray. Using a marker pen, trace the inside of the circle on to the bottom of the tray three times.
2. Lay the large (objective) lens in the center of one of the three large circles. Trace the lens' outline on the circle.
3. Cut the circle with the lens tracing from the tray using the razor blade knife. Be sure to place the styrofoam on a safe cutting surface. Cut out the lens tracing, but when doing so, cut inside the line so that the hole is slightly smaller than the diameter of the lens.
4. Before cutting out the other two large circles, draw smaller circles inside them approximately equal to 7/8ths of the
diameter of the large lens. Cut out both circles inside and out.
5. Coat both sides of the inner circle (the one that holds the lens) with rubber cement and let dry. Coat just one side each of the other two circles with cement and let dry. For a better bond, coat again with glue and let dry.
6. Insert the lens into the inner circle and
press the other circles to either
side. Be careful to align the
circles properly. Because
the outside circles
have smaller
diameters
than the
lens, the
lens is
firmly held
in place. You have completed the
objective lens mounting assembly.
7. Repeat steps 1- 6 for the inside tube and use the smaller lens for tracing. However, because the eyepiece lens is thinner than the objective lens, cut the inner circle from the small tray. The foam of this tray is thinner and better matches the thickness of the lens.
8. After both lens mounting assemblies are