Cast Nylon Rod — Diameters, Lengths & Tolerances
Cast nylon rod is produced through a monomer-casting process that differentiates it fundamentally from extruded nylon rod grades such as PA6 or PA66. In casting, liquid caprolactam monomer is polymerized directly in a mold — this results in a higher-crystallinity Polyamide 6 structure with superior load-bearing capability, improved wear resistance, and significantly larger achievable diameters than extrusion allows. Cast nylon rod is the standard starting material for large-diameter gears, wear plates, bushings, and structural components in heavy industrial applications.
At a glance:
- Diameter range: 1.0" to 12"+ (large diameters are a key advantage of casting vs. extrusion)
- Standard lengths: 2 ft and 4 ft (varies by diameter)
- OD tolerance: ±0.030" to ±0.060" depending on diameter
- Material: Monomer-Cast Polyamide 6 (Cast Nylon 6, PA6-G)
- Production method: Monomer casting — higher crystallinity vs. extruded PA6
- Color: Natural (off-white/ivory)
Standard Diameter Table
Cast nylon rod is particularly valued for large diameters where extrusion is not practical:
| Diameter | Standard Lengths | Notes |
|---|---|---|
| 1.0" | 4 ft | Available in extruded PA6 as well; casting adds density |
| 1.5" | 4 ft | General machining, bushings |
| 2.0" | 4 ft | Heavy-duty bearings and sleeves |
| 3.0" | 2 ft & 4 ft | Gears, rollers, large bushings |
| 4.0" | 2 ft & 4 ft | Heavy industrial components |
| 6.0" | 2 ft | Large-bore machined parts |
| 8.0" | 2 ft | Very large bearings and wear components |
| 10.0"–12"+ | 2 ft | Specialty heavy industrial; confirm availability |
Contact Ready Plastics for non-standard diameters and lengths.
Mechanical Properties
Cast nylon 6 delivers a superior combination of strength, hardness, and load-bearing capability compared to extruded nylon grades:
| Property | Value |
|---|---|
| Tensile strength | 12,300 psi (84 MPa) |
| Tensile modulus | 508,000 psi (3,500 MPa) |
| Compressive stress (10% strain) | 15,000 psi (100 MPa) |
| Tensile strain at break | 25% |
| Izod impact (notched) | 0.6 ft·lb/in (32 J/m) |
| Rockwell hardness | R118 |
| Density | 0.042 lb/in³ (1.1 g/cm³) |
| Max service temp (short-term) | 340 °F (170 °C) |
| Heat deflection temperature (264 psi) | 355 °F (175 °C) |
| Min service temperature | −30 °F (−34 °C) |
| Water absorption (saturation, air) | 2.2% |
| Dielectric strength | 635 V/mil (24 kV/mm) |
| Volume resistivity | >10¹⁴ Ω·cm |
| Flammability (UL 94) | HB |
The higher crystallinity from the casting process gives cast nylon a stiffer, denser structure that outperforms extruded nylon under heavy, sustained loads — making it the preferred choice for large-diameter stock in gears, heavy bushings, and wear components.
Typical Applications
Cast nylon rod is the workhorse material for large machined components:
- Large-diameter gears and sprockets — casting allows sizes impractical with extrusion; excellent tooth strength
- Heavy-duty bushings and plain bearings — low friction and high load capacity replace bronze in many designs
- Wear plates and slide components — high abrasion resistance and good compressive strength
- Sheaves and pulleys — lightweight replacement for metal pulleys in crane and lifting systems
- Industrial rollers — wear-resistant cylindrical components for material handling equipment
- Structural support components — high compressive strength supports heavy static loads
Machining Cast Nylon Rod
Cast nylon rod machines excellently with carbide tooling. Its higher hardness compared to extruded grades provides consistent chip formation and good surface finish quality. Use sharp tools, moderate speeds (300–600 SFM), and manage heat with compressed air or light mist coolant — especially at larger diameters where heat can build up in deep cuts. Cast nylon rod benefits from stress relief annealing on large, complex components to minimize post-machining distortion.
Related
- Cast Nylon Line Card
- Cast Nylon Sheet — flat cast plate for wear surfaces and structural panels
- Cast Nylon Tube — large-bore hollow sections for heavy bearing applications