## Common ground
All options are idler pins made from different metallic materials, used to support or guide belts, chains, or other moving parts in mechanical systems.
## Options at a glance
**7318.29 – Iron/steel**
- **Defining trait:** Highest strength and wear resistance; commonly used in heavy-duty applications.
- **Typical examples:** Conveyor belt idlers, industrial machinery shafts.
- **Best fit when:** Durability and load-bearing capacity are critical.
**7415.33 – Copper**
- **Defining trait:** Excellent thermal and electrical conductivity; resists corrosion.
- **Typical examples:** Electrical contact idlers, precision instruments.
- **Best fit when:** Heat dissipation or electrical grounding is needed.
**7508.90 – Nickel**
- **Defining trait:** High resistance to corrosion and high temperatures.
- **Typical examples:** Aerospace components, chemical processing equipment.
- **Best fit when:** Exposure to harsh environments or elevated temperatures.
**7616.10 – Aluminium**
- **Defining trait:** Lightweight with good corrosion resistance; low inertia.
- **Typical examples:** Automotive belts, robotics, portable devices.
- **Best fit when:** Weight reduction is essential.
**7907.00 – Zinc**
- **Defining trait:** Low melting point; often used in sacrificial coatings or die-cast parts.
- **Typical examples:** Coated idlers, low-cost consumer gear.
- **Best fit when:** Cost-effective, non-load-bearing use with corrosion protection.
**8101.99 – Tungsten**
- **Defining trait:** Extremely high density and hardness; excellent wear resistance.
- **Typical examples:** High-wear industrial rollers, mining equipment.
- **Best fit when:** Maximum durability under extreme abrasion.
**8102.99 – Molybdenum**
- **Defining trait:** High melting point and thermal stability; resists creep at high temps.
- **Typical examples:** Aerospace bearings, furnace components.
- **Best fit when:** Operation in very high-temperature environments.
**8104.90 – Magnesium**
- **Defining trait:** Lightest metal; good machinability but low strength and flammable.
- **Typical examples:** Prototype parts, lightweight consumer devices.
- **Best fit when:** Extreme weight savings are needed (with caution).
**8108.90 – Titanium**
- **Defining trait:** High strength-to-weight ratio and excellent corrosion resistance.
- **Typical examples:** Aerospace, marine, medical equipment.
- **Best fit when:** Need for lightweight, strong, and corrosion-resistant performance.
## Key differences
| Material | Strength | Weight | Corrosion Resistance | Temperature Stability |
|----------------|----------|--------|------------------------|------------------------|
| Iron/Steel | Very High | High | Moderate | Good |
| Copper | Low | Medium | High | Moderate |
| Nickel | High | Medium | Very High | Very High |
| Aluminium | Medium | Low | High | Moderate |
| Zinc | Low | Medium | Moderate | Low |
| Tungsten | Extremely High | Very High | Moderate | Excellent |
| Molybdenum | High | Medium | High | Excellent |
| Magnesium | Low | Very Low | Low | Low |
| Titanium | High | Low | Very High | High |
## How to choose
- Is the idler in a high-load or abrasive environment? → 7318.29 or 8101.99
- Does it need to conduct heat or electricity? → 7415.33
- Is it exposed to chemicals, salt, or high temps? → 7508.90 or 8108.90
- Is weight a major concern? → 7616.10 or 8108.90
- Is cost the main factor? → 7907.00
## Overlaps & pitfalls
A single idler may combine traits (e.g., titanium is strong and light, but also expensive). If multiple materials suit the use case, prioritize based on **main function**: mechanical load, environmental exposure, or weight. No option is inherently "better"—choose by application needs