Indicator on thumb screw indicates approximately 1mm diameter.
- Break carbon rod about 50mm - 75mm long.
- Insert flat end into the hole in the base of the carbon rod sharpener.
- Gently push the rod up into the cutter while rotating it in a clockwise direction. Hold the carbon rod sharpener so that any carbon dust falls into a waste container.
The formed tip should range from 0.4mm to 2mm in length to give the approximate film thickness shown in the table below.
It is often helpful to use a paper or porcelain indicator near the specimen. Approximate grey scale is indicated in the last column of the table.
| IF: | M = mass evaporated W = mass per unit area | W= | M |
| 4o D2 | |||
| D = distance to specimen | W= and t | t p | |
| M | |||
| t = thickness (of carbon) p = density (of carbon) | =V= | 4o D2p or 2l | |
| r = radius of carbon rod l = length of carbon rod v = volume of carbon evaporated | M= | Vp and M = or 2 1p | |
| t= | or 2.1 = r 2.1 | ||
| 4 or 2 1 |
Using the carbon rod sharpener as set, r = 0.5mm. For convenience, D = 100mm (with added block or platform) and the following table can be used directly.
| 1 | t (approximate) | Indication |
| 0.4mm | 2.5nm | Very light |
| 0.6mm | 3.8nm | Light |
| 0.8mm | 5nm | Medium |
| 1.0mm | 6.2nm | Medium-dark |
| 1.5mm | 9.5nm | Dark |
| 2.0mm | 12.5nm | Very dark |
(Refer to electron microscopy textbooks by Hall, Kay, Pease and others.)