STAINLESS STEEL HEXAGON CAP NUTS DIN 917

Hexagon Cap Nuts DIN 917 — DIN 917 is the low-form option in the domed nut family: a shallower dome sits over the bolt end, giving a noticeably lower overall stack height than a standard high-crown domed nut while still fully enclosing the thread for the same corrosion protection and snag-free finish. That reduced height is the entire reason to specify it — anywhere a fully domed nut's extra crown height won't clear surrounding components, but an exposed thread still needs covering for safety or appearance, DIN 917 is the fit. Typical uses include compact machinery, tight enclosures, and general assembly work where axial clearance above the bolt is at a premium; furniture and decorative applications where a lower profile suits the design also often specify this over the taller standard domed nut. The trade-off for the reduced height is less clearance inside the dome itself, so bolt length selection needs even more care than with a standard domed nut — with less room between the top of the thread and the inside of the crown, a bolt that's only slightly too long will bottom out and prevent the joint tightening fully, so it's worth double-checking engagement length before finalising bolt selection on close-tolerance jobs. Mechanically, the dome doesn't affect clamping performance any more than it does on a taller domed nut; it's purely a protective and cosmetic shell over a standard threaded section. There's no locking feature built in — a plain DIN 917 nut relies on friction and correct torque alone, and where locking is also needed on a low-profile domed fastener, checking availability of a nylon insert version is worth doing, since DIN 986 is generally offered at the taller high-crown height rather than this low-form profile. A2 stainless covers most general and decorative uses; A4 is worth the extra cost for outdoor or marine-adjacent fittings. Diameter and pitch match the mating bolt as standard.

FAQs
Is DIN 917 available with a nylon locking insert?
Locking versions such as DIN 986 are generally offered at the taller, standard domed-nut height rather than this low-form profile, so where both a low profile and a lock are needed, availability should be checked before finalising the design.

Why is bolt length more critical with DIN 917 than a standard domed nut?
The shallower dome leaves less internal clearance above the thread, so a bolt only slightly too long is more likely to bottom out against the crown before the joint tightens fully, making careful length selection more important than with a taller domed nut.

What are DIN 917 cap nuts used for?
They are used in applications where a finished, covered bolt end is wanted but space constraints rule out a higher-profile domed nut, such as compact machinery, enclosures, and general assembly work.

Is DIN 917 self-locking?
No, it relies on standard friction and torque with no locking feature. A nylon insert domed nut (DIN 986) should be used where locking is also required, subject to availability at this lower profile.