Phenolic Machined Parts
Phenolic laminates have been the material of choice for machined electrical insulators and structural components in switchgear, motors, and utility equipment for over a century — and for good reason. They combine strong dielectric performance, dimensional stability, low moisture absorption (when sealed), and excellent machinability at a cost that no high-performance engineering plastic can match for high-volume applications.
Federal Materials machines phenolic across all major NEMA grades: XX (paper base, general purpose), CE (canvas base, electrical), LE (linen base, mechanical and electrical), canvas phenolic, and linen phenolic. Every order is machined to customer prints, hot oil dipped as standard for electrical parts, and shipped with full material traceability.
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- Electrical insulators and insulating plates — contoured, drilled, slotted, and profiled
- Arc chutes and arc barriers — switchgear-grade, can include complex profiles and vents
- Terminal boards and panel boards — drilled grid patterns, routed pockets, edge routing
- Coil forms and transformer bobbins — turned from rod on CNC lathe
- Bushings and sleeves — for motor, rotating equipment, and structural applications
- Standoffs and spacers — hex and round, smooth bore or threaded
- Mounting plates and structural brackets — drilled, tapped, counterbored
- Washers and shims — flat and step-ground, phenolic-grade dielectric washers
- High-volume production parts — paper and canvas phenolic are the most cost-effective thermoset for production runs
Phenolic Grade Selection Guide
| NEMA Grade | Filler | Best use |
|---|---|---|
| XX | Paper | General-purpose electrical; most economical |
| XXP | Paper, FR | Flame-retardant paper phenolic |
| CE | Canvas | Better impact resistance; electrical grade |
| LE | Linen | Mechanical and electrical; fine surface finish |
| Canvas Phenolic | Woven cotton canvas | Heavy-duty mechanical, switchgear |
| Linen Phenolic | Woven linen | Fine-machined surfaces, bearing applications |
| GPO-3 | Glass mat | Flame-retardant, polyester-based; arc-track resistant |
Not sure which grade to specify? Include your application details in the RFQ and our application engineers will recommend the right grade.
Typical Tolerances
| Dimension type | Production tolerance |
|---|---|
| Critical turned dims (OD/ID) — canvas/linen grades | ±0.0005" |
| Critical turned dims — paper grades | ±0.001" |
| General machined dims | ±0.005" |
| Flatness (plates ≤ 12") | ±0.005" |
| Thread class | 2B/3B per print |
Tighter tolerances on specific features confirmed at quoting. Canvas and linen grades hold tighter dims than paper grades due to their woven-filler stability.
Finish Options
| Finish | Description |
|---|---|
| Hot oil dip | Standard for all phenolic electrical parts — seals cut surfaces, displaces moisture, extends dielectric life |
| As-machined | Available where oil residue is not acceptable |
| Painted / marked | Customer-specified coating or part marking |
| Machined-to-spec edges | Chamfer, radius, or step-ground to print |
Hot oil dip is the industry-standard finish for machined phenolic electrical components and is included by default on all electrical-application orders.
Standard Turnaround
| Stage | Lead time |
|---|---|
| Quote response | Same business day |
| Prototype / first article (1–5 pcs) | 3–5 business days |
| Short run (6–50 pcs) | 5–10 business days |
| Production run (50+ pcs) | 10–15 business days |
Phenolic is one of the fastest-machining thermosets — production runs turn quickly once material is confirmed in stock.
Materials We Stock (Phenolic Stock Shapes)
| Form | Grades stocked | Sizes |
|---|---|---|
| Sheet / plate | XX, CE, LE, canvas, linen | 0.031" – 4.000" thick; up to 48" × 96" |
| Rod | XX, CE, canvas | ¼" – 6" diameter |
| Tube | CE, canvas | Selected OD/wall; call for availability |
Material certifications to NEMA LI-1 grade available with every order.
Quality & Inspection
- Dimensional inspection — in-process and final; CMM first-article on request
- Dielectric withstand testing — hipot and megohm for electrical insulators
- Hot oil dip process control — temperature and time logged per batch
- Visual inspection — delamination, chip-out, burr-free, surface finish
- Material C of C — NEMA LI-1 grade traceability, lot to part
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Request a Quote →More Related Guides
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