Nylon Insert Jam Nuts, Marine Grade
What are marine grade nylon insert jam nuts? Nylon insert jam nuts combine two ideas: the thin, low profile of a jam nut and the nylon locking collar of a nyloc. The result is a low-clearance nut that resists vibration loosening by nylon friction, for places a full-height lock nut will not fit. In marine service they come in 316 stainless. AlbanyCountyFasteners.com stocks these in 316 stainless steel.
Locking where height is limited
Sometimes you need a vibration lock but do not have room for a full-height nyloc, and that is exactly where the nylon insert jam nut fits. It is thinner than a standard nyloc, so it clears in tight assemblies and on short thread protrusions, while still carrying a nylon collar that grips the bolt thread and resists back-off by friction. On marine hardware that means locking in confined fittings, on shallow studs, or where a stack of components leaves little thread. The trade-offs follow from the two features it combines. Being thin, it engages less thread and carries less load, so like any jam nut it suits locking and positioning rather than primary clamping. Being nylon-locked, it shares the nyloc's temperature ceiling, losing its grip as the nylon softens above roughly 250°F. In 316 the body resists salt, and matched to a 316 fastener it keeps the low-clearance joint corrosion consistent.
Why choose 316 stainless nylon insert jam nuts
- Thin profile locks where a full nyloc will not fit
- Nylon collar resists vibration loosening by friction
- Suits confined fittings and short thread protrusions
- 316 stainless body resists chloride corrosion in salt
- Combines low clearance with vibration locking
Common applications
- Confined marine fittings with limited clearance
- Short studs and shallow thread protrusions
- Locking in tight component stacks
- Low-profile hardware needing vibration resistance
- Instrument and enclosure connections
- Any low-clearance locking joint in salt
Marine Nylon Insert Jam Nut FAQs
How is this different from a standard nyloc?
It is thinner, a jam-height nut with a nylon collar, so it locks by nylon friction like a nyloc but fits where a full-height lock nut will not. The trade is less thread engagement and load capacity.
Can it carry the main load?
Its thinness means less engagement, so it suits locking and positioning rather than primary clamping. Use a full lock nut for the main load and a nylon jam nut where clearance is tight.
Does it have the same temperature limit?
Yes, the nylon softens above roughly 250°F and the lock is lost, the same ceiling as a standard nyloc. Near hot machinery use an all-metal option instead.
Why 316 for this nut?
The body still has to resist salt even though the nylon does the locking. 316 resists chloride pitting, keeping the nut sound in a marine environment.
Can I reuse it?
Limited reuse while the nylon grips, but the insert wears and the lock weakens. Replace when the grip feels reduced for a reliable lock.
Does immersion affect the nylon?
Prolonged immersion lets the nylon absorb water and swell, which can raise running torque. The nylon is not damaged by salt water, but allow for the change in maintenance.