Calculate your required differential thermal clearance instantly. We manufacture custom graphite bearings for extreme temperature, submerged, and dry-running applications.
Enter diameter, temperature, material, and environment to calculate thermal clearance and material grade.
Steel expands 3x faster than graphite. Standard metal-bearing tolerances will cause seizure in high-temperature applications.
Resin is excellent for submerged use (<250°C), while antimony/babbitt is required for high PV loads and dry running (<400°C).
Graphite forms a solid lubricant transfer film, requiring a hard shaft (HRC 45+) with a smooth Ra 8-16 µin finish.
Metal shafts expand outward against the bearing ID at a rapid rate as temperatures rise.
Graphite dimensions remain relatively stable, expanding at only 1/3 the rate of steel.
Our engineering team calculates this exact differential and applies custom CNC tolerances to ensure a safe running clearance at your peak operating temperature.
| Grade | Best Fit | Risks & Limits | Validation Step |
|---|---|---|---|
| Resin-impregnated graphite | Submerged pumps, chemical mixers, food processing (<250°C) | Temperature limit strictly bound by the resin (PTFE, furan, phenolic). | Chemical compatibility check + temperature verification |
| Metal-impregnated (Babbitt / Antimony) | High PV limit (up to 15,000 dry), dry running pumps (<400°C) | Antimony alloys may trigger specific export compliance reviews. Requires hard counterface shaft (HRC 45+). | Max friction temperature calculation and shaft hardness check |
| Electro-graphite / Plain Carbon | High temperature ovens, conveyors (<500°C in air) | Oxidation occurs above 400°C in air; lower structural strength compared to metal-impregnated. | Atmosphere review (air vs inert) + maintenance interval planning |
Prepare these inputs before requesting a quote to ensure an accurate engineering review.
Carbon graphite has a very low coefficient of thermal expansion (CTE) of approximately 4.0 x 10⁻⁶/°C, compared to steel at ~12.0 x 10⁻⁶/°C. As the assembly heats up, the metal shaft expands faster than the graphite ID. The clearance must be calculated for the specific operating temperature to prevent seizure.
Yes. The graphite acts as a solid lubricant, transferring a microscopic film onto the metal shaft. However, the counterface shaft must be hard (minimum HRC 35, ideally HRC 45+) and have a smooth finish (Ra 8-16 microinches) for this transfer film to establish properly without rapid wear.
Typical lead times range from 2 to 4 weeks depending on the grade availability, impregnation process, and CNC machining complexity.
Send your dimensional drawings, shaft material, RPM, load, and operating temperature. We will calculate PV limits, verify thermal clearance, and precision-machine the ideal grade for your application.
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