Spacers

A spacer is a rigid component used to create or maintain a specified distance between two parts in an assembly. Spacers are designed to provide clearance, alignment, load distribution, or mounting height without bearing a structural function themselves.

Common types include cylindrical spacers, washers used as spacers, and threaded spacers such as standoffs. Cylindrical spacers may be hollow and through-belted or feature a shoulder to seat against one surface. Threaded spacers enable a fastener to pass through both components while maintaining a fixed gap. Wheel spacers are a specialized form mounted between a vehicle hub and wheel to adjust offset and appearance. In electronics and instrumentation, spacers position circuit boards, optical elements, or housings with precise separation.

Specialized spacers exist for specific fields. Dental spacers create space between teeth to accommodate braces or other devices. Optical spacers set the gap between lenses or prisms to achieve the desired optical path. In manufacturing and furniture, spacers help align components and maintain uniform gaps during assembly.

Materials commonly used for spacers include metals (such as aluminum and stainless steel) for strength and heat resistance, and plastics (such as nylon or acetal) for electrical insulation, light weight, or corrosion resistance. Tolerances, environmental conditions, and compatibility with fasteners and mating parts influence material choice and finish.

Design and installation considerations include correct inner and outer diameters, wall thickness, thread pitch for threaded spacers, and secure fit to prevent loosening. In some applications, bearing loads, vibration, and alignment requirements dictate the spacer’s geometry and material selection.