PET Rod (Ertalyte) — Bearing-Grade Sizes and Tolerances
Ertalyte PET rod is the primary stock form for machined bearings, bushings, and rollers. Semi-crystalline, bearing-grade PET-P rod holds tight bore tolerances after turning, resists moisture-induced dimensional change, and carries FDA 21 CFR 177.1630 compliance for food-zone components. Both Ertalyte natural (unfilled) and Ertalyte TX (PTFE-filled wear grade) are available as rod.
At a glance:
- Diameter range: 0.500" – 6.0" in 4-ft standard lengths
- Grades: Ertalyte natural (off-white), Ertalyte TX (opaque white, PTFE + solid lubricant)
- OD tolerances: ±0.010" – ±0.040" depending on diameter (machine to final size)
- FDA 21 CFR 177.1630 — both grades
- Primary machining form for bearings, bushings, rollers, and precision wear components
Why Rod Is the Right Form for Bearings
Rod extrusion produces a solid circular cross-section optimized for lathe turning into bushings, bearings, rollers, and pins. Starting from rod stock:
- Minimizes material waste compared to milling from plate
- Provides a centered, uniform grain structure suitable for precision turned bores
- Standard lengths (4 ft) are easy to fixture and saw-cut to blank length before turning
For thin-wall bushings where bore-to-OD concentricity is critical, starting from rod and turning both OD and bore in a single setup achieves the best concentricity.
Available Sizes
Ertalyte Natural Rod
| Nominal Diameter | OD Tolerance | Availability |
|---|---|---|
| 0.500" | ±0.010" | Stock |
| 0.750" | ±0.010" | Stock |
| 1.0" | ±0.015" | Stock |
| 1.25" | ±0.015" | Stock |
| 1.5" | ±0.015" | Stock |
| 2.0" | ±0.020" | Stock |
| 2.5" | ±0.020" | Stock |
| 3.0" | ±0.030" | Stock |
| 4.0" | ±0.030" | Stock |
| 5.0" | ±0.040" | To order |
| 6.0" | ±0.040" | To order |
Ertalyte TX Rod
Ertalyte TX rod is available in the same diameter range but is typically stocked in the most commonly specified bearing sizes (0.500" – 3.0"). Contact FedMat for availability of TX in larger diameters.
Machining PET Rod to Final Dimensions
Ertalyte rod as-extruded carries the OD tolerances in the table above — adequate for rough blanks but not final bearing dimensions. Machine to final size on a CNC lathe using:
- Turning SFM: 400–600 for finishing
- Feed: 0.003–0.006 IPR for finish turning
- Tool: Sharp C-2/C-3 carbide, positive rake
- Bore tolerance achievable: H7 (±0.0005" on small diameters) with reaming
No pre-drying required before machining — Ertalyte's moisture absorption is negligible and does not affect dimensional stability during cutting. Gauging can be done immediately after machining without waiting for moisture equilibration.
For complete machining parameters, feeds, and tooling recommendations, see the PET machining guide.
Grade Selection for Rod Applications
Ertalyte natural: Best for lubricated service, structural wear parts, food-zone components requiring maximum mechanical strength. Translucent off-white color.
Ertalyte TX: Best for dry-running bearings where external lubrication cannot be applied. PTFE + solid lubricant reduces friction coefficient from ~0.25 to ~0.10 and wear factor by ~8×. Opaque white color; slightly lower mechanical strength than natural.
For the grade decision guide, see Ertalyte grades.
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Frequently asked questions — PET FAQ