Nuts & Washers
A connection is only as consistent as its weakest part. Nut grade, thread tolerance and coating have to match the bolt, otherwise the assembly torque no longer corresponds to the preload the designer assumed.
Products in this range
| Product | Reference standard |
|---|---|
| Hex nut | DIN 934 / ISO 4032 / GB/T 6170 |
| Hex flange nut | DIN 6923 |
| Nylon-insert lock nut | DIN 985 / ISO 7040 / GB/T 889.1 |
| Plain washer | DIN 125 / ISO 7089 / GB/T 97.1 |
| Spring washer | DIN 127 / GB/T 93 |
| Serrated flange nut | To drawing |
Matching the nut to the bolt
- Property class. A grade 8.8 bolt is normally matched with a class 8 nut; grade 10.9 with class 10, unless the design specifies a “nut stronger than bolt” arrangement so that failure occurs in the bolt rather than stripping the thread.
- Coating system. Use the same coating on bolt, nut and washer. Mixing a zinc-flake bolt with an electroplated nut changes the friction on each side of the joint and makes the torque coefficient unpredictable.
- Thread tolerance. Nuts need enough clearance to run onto a coated bolt. Hot-dip galvanized assemblies normally use a larger tolerance or are tapped after coating.
- Washers. Plain washers spread the load and protect the surface; spring washers are used to reduce loosening under vibration. Where a defined preload is required, hardened washers are normally specified.
What to send for a quotation
- Nut type and reference standard, or a drawing
- Diameter, pitch and property class
- Coating, matched to the bolt if the assembly is supplied as a set
- Quantity and delivery schedule
Request a quotation or send your drawing
Tell us the specification, grade, coating and quantity — or send a PDF/DWG drawing and we will come back with price and lead time.
Tel / WhatsApp / WeChat: +86 185 3100 8199
FAQ
- Which nut class should be used with a grade 10.9 bolt?
- Class 10 nuts are the usual match. In some designs a stronger nut arrangement is specified so that if overload occurs the bolt fails rather than the thread stripping. Confirm against the design requirement.
- Why do galvanized nuts sometimes not run onto the bolt?
- Hot-dip galvanizing adds a comparatively thick layer, which reduces thread clearance. Galvanized assemblies therefore normally use an adjusted thread tolerance, or the nut is tapped after coating.
- Do you supply bolts and nuts as one set?
- Yes. Supplying the set from the same batch and with the same coating system gives a consistent torque coefficient, which matters when torque has to be verified on site.