POM Rod — Diameters, Lengths & Tolerances
POM rod is round bar stock produced from polyoxymethylene (POM), an engineering thermoplastic engineered for low friction, high stiffness, and excellent dimensional stability. POM is the polymer family that includes both copolymer (POM-C) and homopolymer (POM-H) grades of acetal, and rod stock is the predominant form used for machining precision components such as bushings, gears, rollers, and valve parts.
At a glance:
- Diameter range: 0.125" to approximately 6.0" (standard stock)
- Standard lengths: 2 ft and 4 ft cut lengths
- OD tolerance: close commercial tolerances maintained
- Material: Polyoxymethylene (POM)
- Color: Natural (white/off-white); black grades available
- Very low moisture absorption — excellent dimensional stability in service
Standard Diameter Table
POM rod is stocked across a wide diameter range to support turning, milling, and drilling operations:
| Diameter | Standard Lengths | Notes |
|---|---|---|
| 1/4" (0.250") | 2 ft, 4 ft | Pins, small standoffs |
| 1/2" (0.500") | 2 ft, 4 ft | Bushings, spacers |
| 3/4" (0.750") | 2 ft, 4 ft | Cams, rollers |
| 1" (1.000") | 2 ft, 4 ft | Gears, general machined parts |
| 1.5" (1.500") | 2 ft, 4 ft | Larger machined components |
| 2" (2.000") | 2 ft, 4 ft | Valve bodies, pump components |
| 3" (3.000") | 2 ft, 4 ft | Heavy-section parts |
| 4" (4.000") | 2 ft | Large-diameter applications |
Non-standard diameters available on request. Contact Ready Plastics to confirm current inventory.
Mechanical & Thermal Properties
POM rod delivers reliable mechanical performance for precision machined parts. The following values are representative of the POM family; consult the Ready Plastics datasheet for grade-specific data.
| Property | Value |
|---|---|
| Density | 1.49 g/cm³ |
| Water absorption (24 h / 96 h) | 0.05 / 0.1 % |
| Heat deflection temp. (HDT) | 141 °C / 285 °F |
| Service temp. (long term) | 110 °C / 230 °F |
| Service temp. (short term) | 150 °C / 300 °F |
| Tensile strength | 53 MPa / 7,600 psi |
| Tensile modulus | 3,000 MPa / 435,000 psi |
| Flexural strength | 85 MPa / 12,000 psi |
| Flexural modulus | 3,000 MPa / 435,000 psi |
| Shore D hardness | 81 |
Typical Applications
POM rod stock is machined into precision components across industrial, automation, and consumer product sectors:
- Bushings and plain bearings — low wear rate and self-lubricating behavior reduce maintenance needs
- Gears and worm wheels — high stiffness maintains tooth accuracy under load
- Cam followers and eccentric discs — fatigue resistance supports cyclic applications
- Roller and guide wheels — resists abrasion in conveyor and web-handling systems
- Valve stems and seats — chemical resistance in light-duty fluid-handling environments
- Food and beverage machinery parts — FDA-compliant grades available for hygienic applications
Machining POM Rod
POM rod machines cleanly with standard carbide or HSS tooling. Short, crisp chips help keep the work area clear and support efficient material removal. No special coolant is required, though air blast or light mist cooling is beneficial in high-speed turning. Tight tolerances of ±0.001" are routinely achievable. Allow parts to reach ambient temperature before final measurement to account for slight thermal expansion during machining.