Unthreaded Spacer
Standoffs & Spacers · spacer sleeve · bushing spacer · standoff sleeve
Definition: An unthreaded spacer is a plain cylindrical sleeve slipped over a bolt or screw to hold two parts a fixed distance apart without adding threads.
Anatomy
■ Body■ Hole
Governing standards: Manufacturer specified (no universal standard)
Common Sizes
| Inch | Metric | Head width | Head height |
|---|---|---|---|
| for #6 | M3.5 | 0.19 OD | 1/8–1 long |
| for #10 | M5 | 0.31 OD | 1/4–1-1/2 long |
| for 1/4 | M6 | 0.38 OD | 1/2–2 long |
Representative sizes. Full dimensional data lives in the standards listed below.
Grades & Strength
| Grade | Material | Tensile (psi) | Marking |
|---|---|---|---|
| Aluminum | aluminum | — | None |
| Nylon / stainless / brass | varies | — | None |
Materials
- Aluminum
- Nylon
- Stainless steel
- Brass
Pros & Cons
Pros
- Simple and cheap
- No threading to strip
- Insulating in nylon
Cons
- Needs a bolt or screw through it
- Adds a part to handle
- Slips off if the screw is removed
Typical Uses
- PCB stacking
- Panel spacing
- Shimming
- 3D-printed assemblies
Alternatives & Related
- Round Standoff — Threaded standoff that receives screws
- Flat Washer — Thin spacer for small gaps
Where to Buy
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FAQ
Spacer vs standoff?
A spacer is unthreaded and slides over a screw; a standoff is threaded and receives screws on its ends. Use spacers with through-bolts, standoffs for stacked boards.
Nylon or metal spacer?
Nylon insulates and is light; aluminum is rigid; stainless is strong and corrosion-resistant. Pick by environment and load.