Custom Machined Washers

Standard hardware washers stop at the catalog. When your application demands a specific OD, ID, thickness, or material that no stock washer provides — a G10 dielectric washer for high-voltage isolation, a PTFE thrust washer for chemical service, a phenolic shim for transformer lamination stacking — Federal Materials machines washers to your exact print in any plastic or thermoset laminate we stock.

We machine washers in all diameters and thicknesses, from thin stamping-replacement shims to heavy thrust washers. Flat, stepped, beveled, or contoured — if it can be drawn, we can machine it. No minimum order quantity.

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Washer Types We Machine

  • Flat washers — any OD/ID/thickness combination; face-ground for flatness
  • Step washers — stepped OD or ID for boss-seating or counterbore applications
  • Thrust washers — heavier section, face-ground; for rotating and sliding contact
  • Dielectric washers — G10, FR4, phenolic, PTFE for electrical isolation at bolt locations
  • Transformer shims and spacers — phenolic and G10, close-thickness tolerance stacks
  • Sealing washers — PTFE face washers for flange and fitting isolation
  • Trim washers / finish washers — countersunk or beveled face
  • Custom profile washers — non-round, slotted, keyed, or profiled OD/ID

Material Selection Guide

MaterialKey propertyTypical application
G10Dielectric, strong, moisture-resistantElectrical isolation washers, structural
FR4UL94 V-0 flame ratingUL-listed electrical assemblies
XX PhenolicEconomical, good dielectricTransformer shims, production electrical
CE PhenolicImpact-resistant, canvas-reinforcedSwitchgear, motor components
PEEKHigh-temp, chemical-resistantAerospace, process equipment
DelrinLow friction, high stiffnessMechanical washers, spacers
PTFEChemical inertness, lowest frictionChemical service, sealing faces
TorlonHighest load capacity at tempThrust washers in hot environments
VespelExtreme-temp, vacuum-ratedAerospace and semiconductor service

Typical Tolerances

Dimension typeProduction tolerance
OD and ID (turned)±0.001" standard; ±0.0005" on request
Thickness (face-ground)±0.001" standard; ±0.0005" on request
Flatness±0.001" per inch (face-ground parts)
Concentricity (OD to ID)0.002" TIR standard

All tolerances confirmed at quoting based on material, size, and quantity. Tighter tolerances available — note on print or RFQ.


Finish Options

FinishDescription
As-machined (faced)Turned OD/ID, faced — standard for most plastics
Face-groundGround flat faces for precision thickness and flatness
Hot oil dipStandard for phenolic washers — seals cut edges, moisture protection
As-machined edgesChamfered or radiused per print

Phenolic washers include hot oil dip as standard. All other materials: as-machined unless otherwise noted.


Standard Turnaround

StageLead time
Quote responseSame business day
Prototype / first article (1–25 pcs)2–5 business days
Short run (25–500 pcs)5–10 business days
Production run (500+ pcs)10–15 business days

Washers are high-volume-friendly parts — once setup is dialed in, production pricing improves substantially at volume.


Materials We Stock (Washer Stock Shapes)

MaterialFormsNotes
G10Sheet, rodNEMA LI-1 GP03
FR4Sheet, rodNEMA LI-1 FR4, UL94 V-0
XX PhenolicSheet, rodNEMA LI-1 XX
CE PhenolicSheet, rodNEMA LI-1 CE
DelrinRod, plateDelrin 150
PTFERod, sheetASTM D4894
PEEKRod, plateASTM D6262
TorlonRod4203, 4301

Washers are machined from rod stock (OD turned, ID bored) or from sheet stock (OD profile-milled, ID bored) depending on size and quantity. We select the most efficient blank strategy at quoting.


Quality & Inspection

  • Dimensional inspection — OD, ID, thickness, concentricity; 100% inspection on close-tolerance orders
  • Flatness measurement — face-ground parts measured on surface plate
  • Dielectric testing — available for electrical isolation washers (specify voltage)
  • Material C of C — grade and lot traceability with each order
  • Visual inspection — burr-free edges, surface finish, no voids or inclusions

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