NEMA XX

NEMA XX is a paper-base phenolic laminate — kraft paper saturated with phenolic resin, pressed under heat — designed as the general-purpose mechanical grade for applications where punch-ability and moderate strength matter more than electrical performance.

TL;DR

Chemistry & Reinforcement

NEMA XX is kraft paper (alpha-cellulose pulp) fully impregnated with a phenol-formaldehyde (phenolic) resin. Multiple plies of resin-soaked paper are stacked and pressed at approximately 1,000 psi and 150–175°C. The cure reaction cross-links the phenolic into a rigid, infusible thermoset network. The result is a dark-brown laminate with:

• Reinforcement: Cellulose kraft paper (random fiber orientation)
• Resin: Phenol-formaldehyde (phenolic)
• Color/finish: Dark brown, smooth on bonded faces, slightly rougher on cut edges
• Density: ~1.34 g/cc

The kraft paper gives NEMA XX better punch-ability than glass-reinforced grades — the cellulose fibers cut cleanly without the abrasive fray that glass creates. This makes XX the preferred punch-press stock among the paper phenolic grades.

Key Properties

Typical Applications

NEMA XX's combination of machinability, low cost, and moderate mechanical strength makes it the workhouse of mechanical phenolic applications:

• Gears and cams — low-load, quiet-running gears in instrumentation and small drive mechanisms. Phenolic gears run quietly and dampen vibration compared to metal.
• Spacers, washers, and shims — precision-punch or machine to size for electromechanical assemblies.
• Jigs and fixtures — low-cost tooling blanks for checking fixtures and light-duty drill jigs.
• Mechanical terminal boards — mounting plates in control panels where electrical isolation is secondary to structural function.
• Bearing retainers — light-load cage applications in slow-speed bearing assemblies.

Standard Sizes

NEMA XX sheet is stocked in:

Cut-to-size service is available for most thickness and length combinations. Tighter tolerances (±0.005 in. or better) require precision grinding after initial cut.

Standards Reference

NEMA XX is governed by three primary standards:

1. NEMA LI 1 — the master U.S. laminated insulation standard. NEMA LI 1 Grade XX defines minimum mechanical and electrical requirements. Current edition: NEMA LI 1-2020.
2. MIL-I-24768/11 — military qualified products list (QPL) specification for phenolic laminate. NEMA XX maps to MIL-I-24768 Type PBM (Paper-Base, Mechanical).
3. ASTM D709 — Standard Specification for Laminated Thermosetting Materials. Covers testing methods for all phenolic laminates.

When ordering to military QPL requirements, request the manufacturer's QPL certification and lot-specific test reports.

Comparison to Neighbor Grades

Choose XX when: you need low-cost mechanical machining stock and electrical properties are not a design requirement. Choose XXX when: the part must provide electrical insulation in addition to structural function. Choose XXX-P or XXX-PC when: high-volume punch-press production requires clean, fast hole punching.

More related guides

Other paper phenolic grades

• NEMA XXX Electrical Grade
• NEMA XXX-P Post-Formable
• NEMA XXX-PC Cold-Punch

Compare phenolic families

• Canvas Phenolic (NEMA C/CE)
• Linen Phenolic (NEMA L/LE)
• Glass Phenolic (NEMA G3–G11)

All grades index

• NEMA Grades Directory