NEMA C

NEMA C is the mechanical-grade canvas phenolic laminate — woven cotton canvas (not paper) impregnated with phenolic resin, producing a laminate with substantially higher impact strength and toughness than paper-base phenolics, optimized for gears, bushings, and structural mechanical parts.

TL;DR

Chemistry & Reinforcement

The defining difference between canvas phenolic and paper phenolic is the reinforcement: woven cotton canvas instead of kraft paper. The interlocked warp-and-fill weave of cotton canvas distributes impact loads through the fiber network, dramatically increasing toughness compared to the random, short-fiber architecture of paper.

• Reinforcement: Plain-weave woven cotton canvas (heavy grade, typically 8–12 oz/yd²)
• Resin: Phenol-formaldehyde (phenolic)
• Color/finish: Dark brown to tan, with visible canvas weave texture on cross-section
• Density: ~1.30–1.35 g/cc

NEMA C is the base canvas phenolic, analogous to NEMA XX in the paper family. The "C" designation implies mechanical service; the CE grade adds electrical performance requirements on top of the C baseline.

Key Properties

Typical Applications

Canvas phenolic grade C is the go-to mechanical thermoset laminate when paper phenolics lack the toughness for the job:

• Spur and helical gears — quiet, vibration-damping gears in printer drives, conveyor indexing, and instrument mechanisms. Canvas reinforcement handles tooth loading without brittle fracture.
• Worm wheel blanks — canvas phenolic worm wheels mesh against metal worms in low-to-moderate duty drives without metal-to-metal wear.
• Plain bearings and bushings — the original phenolic bearing material. Canvas reinforcement supports shaft loads; phenolic resin provides a smooth, self-lubricating surface with light oil.
• Wear strips and slide pads — attached to equipment frames where metal-on-metal wear would cause particle contamination or noise.
• Bearing cages and retainers — pressed-in retainer rings in slow-speed, moderate-load bearing assemblies.
• Structural spacers and brackets — where mechanical robustness matters more than electrical insulation.

Standard Sizes

Canvas phenolic rod is particularly well-stocked for turned gear and bushing blanks. Large-diameter rod (3–6 in.) is available from specialty laminators for heavy-duty gear applications.

Standards Reference

1. NEMA LI 1 — Grade C is defined with requirements for flexural strength, impact, and dimensional tolerances. NEMA LI 1-2020 is current.
2. MIL-I-24768/3 — Military canvas phenolic mechanical grade. Type CBM (Cotton-fabric-Base, Mechanical). QPL required for defense applications.
3. ASTM D709 — test method standard underlying NEMA LI 1 property requirements.

Comparison to Neighbor Grades

Choose C when: impact and machinability are the priority and electrical insulation is not required. Choose CE when the canvas phenolic part must also serve as an electrical insulator.

More related guides

Canvas phenolic grades

• NEMA CE Canvas Phenolic Electrical Grade

Compare canvas to other phenolics

• Linen Phenolic L Grade
• Linen Phenolic LE Electrical Grade
• Paper Phenolic XX Mechanical Grade

All grades index

• NEMA Grades Directory