Rockwell Hardness Scale
| Material | Hardess (R) |
| High-density Polyethylene | 40 |
| Low-density Polyethylene | 10 |
| Polyvinlychloride | 110 |
| Polypropylene | 90 |
| Polystyrene | 75 |
| Polyesters | 120 |
| Acrylics (Lucite) | 130 |
| Polyamides (nylon 66) | 121 |
| Cellulosics | 50 to 115 |
| ABS | 95 |
| Polycarbonates | 118 |
| Acetals | 120 |
| Polytetrafluoroethylene (Teflon) | 70 |
| Phenolics (phenolformaldehyde) | 125 |
| Urea-melamine | 115 |
| Epoxies | 90 |
-42%
30%