G11 Rod — Diameters, Lengths & Tolerances
G11 rod is round bar stock produced from NEMA G-11 glass-reinforced epoxy laminate, a high-performance thermoset composite built on woven fiberglass cloth and high-temperature epoxy resin. With a continuous service temperature of 180 °C (355 °F) and tensile strength of 63,000 psi, G11 rod is the preferred starting stock for machined insulators, spacers, standoffs, and structural bushings in power electronics, motor drives, and industrial switchgear where G10 rod reaches its thermal limits.
At a glance:
- Diameter range: 0.250" to 4.0"
- Standard lengths: 4 ft and 8 ft
- OD tolerance: ±0.005" on smaller diameters; ±0.010" on larger diameters
- Material: NEMA G-11, glass-fabric/epoxy thermoset laminate
- Production method: Compression-molded and ground to round
- Color: Natural yellow-green
Standard Diameter Table
G11 rod is stocked in the following standard sizes at Ready Plastics:
| Diameter | Standard Lengths | Notes |
|---|---|---|
| 0.250" | 4 ft & 8 ft | Common standoff/bushing blank |
| 0.375" | 4 ft & 8 ft | |
| 0.500" | 4 ft & 8 ft | |
| 0.750" | 4 ft & 8 ft | |
| 1.000" | 4 ft & 8 ft | Popular insulator blank |
| 1.500" | 4 ft & 8 ft | |
| 2.000" | 4 ft | |
| 3.000" | 4 ft | Larger structural blanks |
Custom diameters and lengths are available by request.
Mechanical & Electrical Properties
| Property | Value |
|---|---|
| Tensile strength | 63,000 psi (430 MPa) |
| Flexural strength (LW, 0.125") | 75,000 psi (515 MPa) |
| Compressive strength | 37,000 psi (255 MPa) |
| Shear strength | 22,000 psi (150 MPa) |
| Bond strength | 2,200 psi (15 MPa) |
| Hardness (Rockwell M) | 112 |
| Izod impact strength (49 °C, LW) | 12.00 ft·lb/in |
| Specific gravity | 1.82 |
| Water absorption (24 hr) | 0.20% |
| Flammability rating | UL 94HB |
| Maximum continuous service temp | 180 °C (355 °F) |
Typical Applications
G11 rod is commonly machined into the following components:
- High-voltage insulators and standoffs — maintains dielectric integrity at sustained elevated temperatures
- Bushings and sleeve bearings — excellent compressive strength resists crushing loads
- Structural spacers and support posts — used in transformer assemblies, motor controls, and bus bar hardware
- Terminal blocks and connector bodies — low moisture absorption preserves surface resistivity
- Fixture components — dimensional stability under thermal cycling
- Jigs and test fixtures for high-temperature electrical testing environments
Machining G11 Rod
G11 rod machines cleanly on conventional CNC lathes and mills. Use sharp carbide tooling with moderate feed rates and consistent chip removal to prevent delamination at cut edges. Dry machining or light air blast is preferred — coolant is acceptable but should be kept off finished surfaces to avoid temporary moisture uptake. Saw cutting with carbide-tipped blades produces clean square ends; abrasive wheels work well for close-tolerance parting. Always machine to final dimension before any heat exposure, as the thermoset matrix will not re-soften.
Related
- G11 Glass Epoxy — Line Card
- G11 Sheet — flat stock for panels, gaskets, and laminated insulators
- G11 Tube — hollow sections for sleeves, conduits, and coil forms
- G10 Rod — standard-temperature glass-epoxy round bar, a lower-cost alternative for sub-130 °C service
- FR5 Rod — flame-retardant counterpart with equivalent thermal performance