Non-metallic spacers and standoffs help maintain accurate distances between components while offering material properties that metal parts may not provide. From supporting circuit boards to separating panels and positioning sensors, these small components can play an important role in an assembly’s performance.
Choosing the right part involves more than specifying its length. The material, fixing method, and operating environment all influence whether it will maintain the required spacing throughout its service life.
What are non-metallic spacers?
A spacer is a component placed between two parts to maintain a defined gap. A typical plain spacer is a cylindrical sleeve with an unthreaded bore, allowing a screw or bolt to pass through its centre.
For example, a spacer can sit between a mounting plate and a protective cover. Tightening the fastener secures the assembly, while the spacer establishes the separation between the surfaces.
Polymer spacers can also provide an insulating barrier at the contact surfaces. However, a metal screw passing through the bore can still create an electrical path unless the complete fixing arrangement is designed to prevent it.
What are non-metallic standoffs?
A standoff supports one component at a set distance from another and commonly incorporates threads or a retaining feature. Threaded versions combine spacing with a fixing point, making them useful where components need to be mounted, stacked or removed for maintenance.
Common configurations include:
- Female-to-female: internal threads at both ends, accepting separate screws.
- Male-to-female: an external threaded stud at one end and an internal thread at the other.
- Male-to-male: external threaded studs at both ends.
- Snap-fit supports: retaining features that locate in suitable mounting holes.
Round and hexagonal bodies are available; hexagonal flats provide a surface for a suitable assembly tool. Product terminology varies, so check the drawing rather than relying on the words “spacer” or “standoff” alone.
Spacers and standoffs compared
| Feature | Plain spacer | Threaded standoff |
| Main function | Maintains a gap between parts | Maintains a gap and provides a fixing point |
| Typical construction | Sleeve with an unthreaded bore | Body with internal or external threads |
| Fastening arrangement | A separate fastener passes through | Screws or nuts engage with the standoff |
| Example use | Separating a cover from a mounting plate | Mounting a circuit board above a chassis |
Why choose a non-metallic component?
Electrical insulation
An insulating polymer can help separate electrically active components from surrounding structures. This is useful in circuit board mounts, sensor assemblies and electrical enclosures.
Non-metallic does not automatically mean electrically insulating. Conductive and static-dissipative polymer grades exist, and carbon-based additives can change electrical behaviour. Specify the electrical properties of the exact grade and assess the complete assembly, including screws and inserts
Lower component weight
Many engineering polymers have lower densities than common engineering metals. Replacing a metal spacer with a suitable polymer version can reduce component weight, particularly when an assembly contains numerous mounting points. The final saving depends on the material and any changes needed to the design.
Resistance to corrosive environments
Polymer components avoid the rusting associated with unprotected steel. Suitable materials can also withstand chemical exposure, making them worth considering for laboratory equipment and industrial processing assemblies.
Chemical resistance remains specific to the polymer, chemical, concentration and temperature. A material suitable for occasional splashes may not suit continuous immersion or a hot cleaning cycle.
Reduced heat transfer
Many unfilled polymers conduct less heat than metals. A polymer spacer may therefore help limit heat transfer through a mounting point. The result depends on its geometry and the other thermal paths in the assembly; a metal fastener can still conduct heat across the gap.
Which materials are used?
“Non-metallic” includes polymers, composites, and ceramics. For polymer spacers and standoffs, the following materials provide useful starting points for selection.
| Material | Reasons to consider it | Main selection considerations |
| PA nylon | General-purpose mechanical performance and established use in mounting hardware | Moisture absorption can affect dimensions and properties |
| POM acetal | Machinability, stiffness and relatively low moisture uptake compared with common nylons | Confirm temperature and chemical compatibility |
| PEEK | Mechanical performance at elevated temperatures and resistance to many chemicals | Select the grade against load, temperature and insulation requirements |
| PTFE | Broad chemical resistance and low friction | Creep under compression can affect retained spacing |
| PVDF | Chemical resistance and low moisture absorption | Check chemical exposure and mechanical loading at operating temperature |
When are custom spacers and standoffs useful?
Custom parts are useful when standard sizes cannot meet the required mounting height, bore, thread arrangement or material specification. CNC machining can produce bespoke polymer spacers and standoffs from suitable stock shapes, while injection moulding may suit repeat production where the geometry and quantities justify tooling.
A useful drawing should identify the critical dimensions, material grade, tolerances and inspection requirements. Sharing the component’s function also helps establish which features matter most.
Choosing the right component
A plain spacer is often a straightforward choice when a through-bolt can secure the assembly. A threaded standoff is useful when the spacing component also needs to provide a mounting point.
For polymer spacers and standoffs, reliable selection means matching the geometry and material to the load, environment, and service life. Whether the priority is electrical insulation, chemical resistance, or reduced weight, the finished assembly should be checked under representative conditions.