STAINLESS STEEL FINE PITCH NYLON INSERT NUTS DIN 985

Fine Pitch Nylon Insert Nuts DIN 985 — DIN 985 is the fine-pitch nyloc: the same nylon-collar locking principle as a standard nylon insert nut, but cut with a finer thread pitch that packs more threads into the same length, increasing tensile stress area and giving the joint better resistance to vibrational loosening even before the nylon's own prevailing torque is factored in. That combination of two independent anti-loosening effects — finer thread friction plus polymer grip — is why DIN 985 turns up so often in automotive, motorsport, and precision engineering assemblies, where both vibration and space are typically tighter constraints than in general industrial work. It behaves identically to a standard-pitch nyloc in every other respect: the nylon insert has a bore slightly smaller than the thread, so the bolt deforms it on the way through, generating continuous friction that holds even without clamp tension; it can be reused a limited number of times before that grip weakens with each refitting, and safety-critical joints should get a new nut after removal rather than the same one repeatedly; and standard nylon's temperature ceiling still applies, so an all-metal locking nut is the better choice for anything running hot. The one thing that can't be substituted is the thread pitch itself — a fine pitch DIN 985 nut must be paired with a fine-thread bolt of the same nominal diameter; it will not run correctly onto a coarse thread fastener. A2 stainless is adequate for the majority of general fine-pitch locking applications; A4 is worth the extra cost in marine or continuously wet environments, though these nuts are more often chosen for their mechanical properties than for corrosion resistance alone. Confirming the mating bolt's exact pitch before ordering is the key sizing step, since fine and coarse variants look almost identical at a glance.

FAQs
Does the fine pitch add meaningfully more locking force than a standard nyloc?
It adds a modest amount of extra thread friction, but the dominant locking mechanism in both cases is still the nylon collar; the fine pitch's main practical benefit is the increased tensile strength and finer adjustment, not a dramatically stronger lock.

Can a DIN 985 fine pitch nut be substituted with a coarse pitch nyloc if fine pitch stock runs low?
No, the pitch must match the mating bolt exactly; a coarse thread nut will not engage a fine thread bolt regardless of how similar the two look.

Is this nut reusable like a standard nyloc nut?
As with all nylon insert nuts, it can be reused a limited number of times, but the nylon's grip weakens with each removal and refitting. Safety-critical joints should use a fresh nut.

Does this nut need any different tooling to fit compared with a standard nyloc?
No, standard spanners or sockets are used in the same way; the only practical difference from a coarse-pitch nyloc is that it takes more turns to run down the same length of thread.