Product and application brief
A captive washer nut combines a threaded nut and a separate washer retained as an assembly. The washer is not simply the integral flange of a one-piece flange nut. Its profile, retention arrangement and permitted movement belong to the selected product drawing. This page explains product identification; it does not establish a locking result or a stocked range.
Product forms and reference names
| Choice or field | What to identify |
|---|---|
| Captive tooth washer | A separate toothed washer is retained with the nut. Bossard BN 1364 identifies this construction; record the actual tooth geometry and bearing-side orientation. |
| Captive conical spring washer | A separate dished washer is retained with the nut. Bossard BN 712 identifies this form; its profile is not the same as a flat or toothed washer. |
| Rotating captive washer with locking nut | Bossard BN 33966 identifies a specific all-metal nut with a rotating captive washer. Rotation and the nut locking mechanism are separate features, not universal attributes of every washer nut. |
| Drawing-defined assembly | Where another washer profile or nut body is required, identify both components and their retained-assembly envelope on a controlled drawing. Do not substitute from a family name alone. |
Separate washer versus integral flange
An integral flange belongs to the nut body. A captive washer is a distinct retained component, visible as a separate interface beneath the nut. Similar outside diameters do not make these constructions interchangeable: nut height, washer profile, contact area and movement can differ.
Retention, movement and bearing surface
State whether the selected washer is intended to rotate relative to the nut and what axial movement, if any, is allowed. A captive description establishes retention, not a universal free-spinning requirement. Identify the bearing face, tooth or conical profile and the mating surface; do not infer contact protection or locking behaviour from appearance.
Locking features need independent evidence
A retained washer, a toothed bearing face and a prevailing-torque nut are different features. A manufacturer's specified combination may incorporate more than one. Required vibration resistance, clamp behaviour, prevailing torque, installation values and permitted reuse must come from the selected assembly specification and verified tests.
Catalogue identity and procurement boundary
BN 1364, BN 712 and BN 33966 are primary catalogue examples used to distinguish structures. Their brand-specific property designations, coatings and functional descriptions are not FastenerBridge product claims. No common DIN/ISO conformity, dimensions or interchangeability is asserted for the complete family.
Specification fields
| Choice or field | What to identify |
|---|---|
| Nut identity and thread | Exact part/drawing revision; metric or inch thread, diameter, pitch/TPI, fit and handedness. |
| Nut body | Overall and wrenching height, across flats, bearing interface and any independently specified locking feature. |
| Washer geometry | Outside/inside diameter, thickness, flat/tooth/conical profile, tooth direction and specified bearing-face orientation. |
| Retained assembly | Retention geometry, assembly overall envelope, permitted rotation/axial movement and retention inspection requirement. |
| Materials and finish | Nut and washer material/designation separately; surface and lubrication condition for each component. |
| Mating joint and inspection | Bolt/stud, contact material/surface, assembly specification and required test documents; quantity and size schedule. No universal torque or delivery promise. |
Common product questions
Is a captive washer nut the same as a flange nut?
No. The captive washer is a separately retained component. An integral flange is part of the nut body. Match the drawing and joint requirements rather than outside diameter alone.
Does every captive washer rotate freely?
No universal movement requirement is established here. Some manufacturer assemblies explicitly use rotating washers. Specify the permitted rotation and axial movement for the selected part.
Does a captive washer guarantee locking or safe reuse?
No. Washer retention, bearing-face action and a nut locking feature are distinct. Performance, installation and reuse require the applicable assembly specification and verified evidence.
Related product choices
Product references
References checked 9 October 2026 identify structures, not FastenerBridge stock, certification or brand affiliation. Final requirements follow the selected specification. No universal dimensions, load rating or tightening torque is stated.