Quick Answer
G10 spacers, standoffs, and bushings are non-conductive spacing components CNC-machined from NEMA-grade epoxy fiberglass laminate (G10, FR4, G11, FR5). They maintain fixed spacing and electrical isolation between boards, panels, busbars, and hardware — cut to any length, diameter, and thread requirement from your drawing. IncomePultrusion machines custom spacers, shoulder washers, sleeves, and bushings with a 24-hour quote turnaround.
Spacers, Standoffs, Sleeves, and Bushings from Epoxy Laminate
Washers get the attention, but many assemblies need more than a thin ring: a fixed gap between a board and a chassis, a busbar held off a steel rail, a bolt isolated along its full length through a thick panel. That is the job of spacers, standoffs, sleeves, and bushings — and machined G10/FR4 laminate is a practical material for all of them: rigid, dimensionally stable, non-conductive, and machinable to any geometry a drawing can define.
Unlike catalog metal or nylon standoffs, laminate spacers are produced to order: any outer diameter, any bore, any length, with slots, flats, chamfers, or coarse threads added in the same setup. Because there is no molding tooling, prototypes and small-to-medium batches stay economical.
Part Types
| Part | What It Does | Typical Use |
|---|---|---|
| Round spacers / standoffs | Maintain a fixed gap between two parts | Board-to-chassis spacing, panel stacking, busbar separation |
| Shoulder (step) washers | Isolate the bolt shank as well as the clamping face | Through-bolts in clearance holes, panel jacks, instrument mounting |
| Sleeves / tubular bushings | Full-length isolation of a bolt or shaft through a panel | Thick-panel galvanic isolation, pivot bushings, guide sleeves |
| Profiled standoffs | Spacing plus location — flats, steps, or threads | Terminal boards, switchgear internals, jig plates |
For flat washers and complete bolt-isolation kits, see the custom insulating washers hub. For panels, plates, and other flat machined parts, see G10 & FR4 machined parts.
Material Grades
All parts are machined from certified NEMA-grade laminate sourced from qualified mills:
- G10 — general-purpose grade, ~130 °C continuous, no flame rating
- FR4 — flame-retardant (UL94 V-0 class), ~130 °C continuous; the default for electrical panels
- G11 / FR5 — high-Tg grades for 155–180 °C service; see G11 & FR5 high-temperature laminate
Grade definitions and property tables are in the G10 material guide.
Sizes, Tolerances, and Secondary Machining
- Outer diameter: from a few millimeters to large insulating sleeves, per drawing
- Bore: matched to bolt or shaft size — metric M3–M24 and imperial #4–1 in hardware covered as standard
- Length: cut to specification, from short spacer rings to full-length standoff tubes
- Tolerances: ±0.1–0.3 mm typical; tighter quoted on request
- Secondary features: slots, cross-holes, flats, chamfers, stepped ends, coarse internal/external threads (inserts recommended for repeated assembly)
Typical Applications
- Electrical panels and switchgear: non-conductive standoffs and spacers that cannot create a ground path
- Busbar and battery racks: spacing plus isolation between copper/aluminum conductors and steel structure
- Galvanic isolation: sleeves and shoulder washers that keep stainless hardware from touching aluminum frames — including the bolt shank
- Instrument and electronics mounting: shoulder washers and standoffs for floating panels, jacks, and connector shells
- High-temperature fixtures: G11/FR5 spacers near motors, transformers, and power electronics
Frequently Asked Questions
What is the difference between a spacer, a standoff, and a bushing?
A spacer maintains a gap and is usually a plain tube or ring. A standoff is a spacer with locating features — threads, steps, or flats — that position the parts it separates. A bushing (sleeve) lines a hole to isolate or guide a bolt or shaft along its full length. All three can be machined from the same G10/FR4 laminate.
When do I need a shoulder washer instead of a flat washer or spacer?
When a bolt passes through a clearance hole and the shank must not touch the hole wall. A flat washer only isolates the clamping face; the shoulder on a step washer centers the bolt and isolates the shank. For thick panels, a full-length sleeve does the same job over a longer path.
Can G10 spacers be threaded?
Yes, for coarse threads. Laminate threads are adequate for clamping but wear under repeated assembly — use metal thread inserts when the joint will be opened and closed regularly.
Are G10 spacers non-conductive?
Yes. G10/FR4 laminate is an electrical insulator (typical dielectric strength 16–22 kV/mm perpendicular). Keep surfaces clean and dry for high-voltage service.
What sizes can you make?
Parts are machined to drawing, not picked from a catalog — any OD, bore, and length within laminate stock limits. Send the drawing or dimensions for confirmation.
Which grade should I specify?
FR4 for general electrical panels (flame retardant), G10 when no flame rating is required, and G11/FR5 for service above 130 °C. If the RFQ says “FR10” or “FR11”, send the temperature and flame requirements — those names map to standard or high-temperature grades respectively.
What do you need for a quote?
Grade, OD × bore × length, quantity, tolerances, any threads or secondary features, and the operating environment (voltage, temperature, moisture). Submit through the quote request page for a 24-hour response.
Request a Quote for G10/FR4 Spacers & Bushings
Send your drawing or dimensions through the quote request page. Spacers, shoulder washers, sleeves, and bushings are quoted within 24 hours, with material datasheet support and prototype machining available before production quantities.