15 · Lock nut · vibration hold on print
Nylon-insert vs prevailing-torque lock nuts on RFQ drawings
On stone cladding brackets, structural splices, and heavy baseplate joints, a vague “lock nut” line forces dual quotes. Nylon-insert (Nyloc-style) and prevailing-torque all-metal nuts behave differently under heat, reuse, and vibration. This desk locks which style the controlling revision owns — plus reuse / temperature notes — before any unit price is useful. Dashitou does not publish brand charts, μ tables, or “never loosen” guarantees here.
Define · what this RFQ is for
Use this desk when overseas buyers quote Dashitou stone · structural · heavy fasteners and the print must choose a locking nut style — nylon-insert vs prevailing-torque (all-metal) — for vibration hold, service temperature, or reuse rules. You own joint design and engineer sign-off; we confirm which nut style appears on the revision, diameter × length, grade / finish lock, and qty band against that revision.
Pair with torque vs preload vs proof load (G13) when clamp figures sit beside the lock-nut callout, A2 vs A4 coastal cladding (G10) when atmosphere drives stainless grade, stainless galling prevention (G14) when stainless-on-stainless threads meet a lock nut, structural bolt class & coating (G8) when class/finish sit with the nut set, and drawing handoff for revision lock. Then open Enquire / RFQ.
Discuss · fields that change the quote
Each row below is a desk check. Missing rows stay Open — we do not invent nylon brands, prevailing-torque classes, or “one-time use forever” rules on this public page.
Field desk · 01–06
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Lock-nut style (nylon-insert vs prevailing-torque) Name nylon-insert (polymer collar) vs all-metal prevailing-torque (deformed thread / elliptical / beam). “Lock nut” alone invites dual quotes. Prefer the print’s named style or mark Open with a preference rule.
- Email example: Prevailing-torque all-metal lock nut · nylon-insert forbidden (Rev C)
- If missing: Open — do not assume Nyloc from a catalog photo
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Service temperature / heat note Nylon inserts soften or lose grip above the polymer’s service band. Hot zones, powder-coat bake, or furnace-adjacent steel often force all-metal. Write the temperature note when the revision owns it; otherwise mark Open with a preference.
- Email example: Service > polymer limit · all-metal prevailing-torque only
- If Open: mark preference on the print or RFQ notes
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Reuse / one-time rule Many nylon-insert and some prevailing-torque nuts are one-time or limited-reuse under buyer standards. If the site re-torques or reuses hardware, name the reuse rule beside the style. Do not invent cycle counts on this desk.
- Email example: One-time nylon-insert; no field reuse (Rev C)
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Diameter × length & washer pack Lock diameter × length with grip/engagement and whether a flat washer sits under the nut. Prevailing-torque nuts can change under-head / under-nut bearing feel — write washer rules explicitly when the stack includes isolation pads.
- Email example: M16 × 70; nylon-insert lock nut + flat washer under nut
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Qty band & destination Mock-up joint set vs project lot; destination for packing notes. Discussion band is enough for the first reply.
- Email example: Qty band: mock-up 80 pcs → project lot TBD · dest EU
What must appear on the print
- Lock-nut style named (nylon-insert vs prevailing-torque all-metal)
- Service temperature / heat note when exposure drives the choice
- Reuse / one-time rule when site practice owns it
- Grade / finish lock with the mating bolt — see A2 vs A4 coastal · torque / preload
- Controlling revision — see drawing handoff
Agree · before we number
Until the following are aligned, treat any figure as discussion only:
- Controlling revision locks nylon-insert vs prevailing-torque (or marks Open with a preference)
- No invented nylon brands, “never loosen” claims, or site reuse-cycle tables posted as policy here
- Grade (G10), torque/preload (G13), and galling (G14) notes settled or linked in the same thread when those desks apply
- Samples and private-label marking only after nut style, temperature/reuse notes, and diameter × length are clear
We do not invent certificates, plant area, or ranking badges here. Project documents that matter to the RFQ are shared privately when relevant.
FAQ · nylon-insert vs prevailing-torque lock nuts
Is “lock nut” on the BOM enough to quote nylon-insert or prevailing-torque?
Usually no. Nylon-insert and all-metal prevailing-torque nuts are different products with different heat and reuse behavior. Name the style on the controlling revision, or mark Open with a preference rule. Vague “lock nut” language often forces a resubmit.
When should an RFQ lock prevailing-torque instead of nylon-insert?
When service temperature, bake cycles, or engineer rules put the joint above the polymer’s service band, or when the print forbids nylon. Do not swap styles on this public desk without the print. Write the temperature / reuse note beside the callout.
Does a lock nut replace naming torque or preload on the print?
No. Lock-nut style is a retention / vibration-hold choice. Installation torque, preload, and proof-load language remain separate lines — see the torque vs preload desk. Treat them independently on the RFQ and the print.
Can one RFQ mix nylon-insert and prevailing-torque zones?
Yes, when zones are explicit on the BOM (for example nylon-insert on cool cladding brackets, all-metal on hot structural splices). Ambiguous “lock nut OK” without zone ownership often splits the quote. Lock zones or mark Open with a preference rule.
What should I send so Dashitou can review the lock-nut line cleanly?
Open Enquire / RFQ, then email the PDF/STEP or marked sketch to shizhanhao6@gmail.com in one thread. Include lock-nut style, temperature/reuse notes if relevant, A2/A4 or class/finish if relevant, diameter × length, qty band, and destination. Skim G10, G13, and G14 when those desks apply. No cart; no list prices on this site.
Next step
Skim torque / preload RFQ · A2 vs A4 coastal RFQ · stainless galling RFQ · RFQ checklist, then open Enquire / RFQ. Direct email: shizhanhao6@gmail.com.