PET Tube (Ertalyte) — Bearing Tube Sizes and Selection
Ertalyte PET tube provides a near-net-shape starting point for machined bearing shells, bushing blanks, and ring components where a pre-drilled bore reduces material removal and setup time. Tube stock is particularly valuable for large-diameter bushings where solid rod would require significant boring time to reach the design bore diameter.
At a glance:
- Available in OD from ~1.0" with various ID/wall combinations
- Reduces material waste vs solid rod for large-bore bearings
- Natural and TX grades available (TX tube availability: confirm with Ready Plastics)
- FDA 21 CFR 177.1630 compliant
- OD tolerance: ±0.015" to ±0.040" depending on size; wall tolerance ±0.015"
When to Use Tube vs Rod
Rod is the standard starting form for most Ertalyte bearings and bushings. When you need a 1.0" bore bushing, 1.5" diameter rod leaves only 0.250" per side for turning — efficient.
Tube becomes the better choice when:
- The final bore diameter is large relative to the OD (thin-wall bushing)
- High-volume production where reducing boring time saves cycle time
- Large-diameter bearing rings (>3.0" bore) where solid rod boring is time-consuming
Example: A bushing with 3.0" bore, 3.5" OD, 2.0" long. From 3.5" rod, you would bore the entire 3.0" bore (heavy cut). From 3.0" × 3.5" tube, you only need to finish-bore to the final diameter — much faster.
Available Tube Sizes and Tolerances
Standard tube sizes for Ertalyte are produced in OD/ID combinations; not all combinations are stocked. Common combinations include:
| OD (nominal) | ID (nominal) | Wall | Notes |
|---|---|---|---|
| 1.5" | 0.750" | 0.375" | Stock |
| 2.0" | 1.0" | 0.500" | Stock |
| 2.5" | 1.25" | 0.625" | Stock |
| 3.0" | 2.0" | 0.500" | Stock |
| 3.5" | 2.5" | 0.500" | To order |
| 4.0" | 3.0" | 0.500" | To order |
OD tolerances: ±0.015" (small OD) to ±0.040" (large OD). Wall thickness tolerance: ±0.015". Concentricity (wall uniformity): ±0.020" for most standard tubes. Bore must be finish-machined to final size — as-extruded ID is a nominal starting point, not a precision bore.
Machining Tube
Tube fixturing requires attention to avoid deforming thin-wall sections. Use soft jaws or mandrel support when the wall-to-OD ratio is below 15%. For finish-boring the ID after fixturing on OD, reduce chuck pressure and take lighter finishing passes to minimize workpiece deflection.
Turning parameters are the same as for Ertalyte rod — see the PET machining guide for complete parameters.
Quote Ertalyte tube — confirm OD/ID availability
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Frequently asked questions — PET FAQ