Cartridges must be fitted as tightly as possible.
When preparing to drill holes for placing the heaters, consider the following factors:
If possible, a hole should be drilled at the opposite end of the connections to facilitate easier extraction of the cartridge.
 
                    1. Drilling for extraction
2. Mold
3. Resistance
| Material | p | Fusion | Cp | Cf | 
| Steel | 7.8 | 1400 | 0.12 | 60 | 
| Aluminium | 2.7 | 600 | 0.23 | 94 | 
| Bronze | 78.4 | 900 | 0.10 | |
| Casting | 4.2 | 1150 | 0.13 | 30 | 
| Stainless Steel | 7.8 | 1600 | 0.12 | 56 | 
 
                1. Resistance
2. Probe
3. Maximum 15 millimeters
4. Maximum fit