Heavy-Duty M6-M64 Slotted Nuts: The Ultimate Safety Locking Fastener
Our M6-M64 Slotted Nuts, frequently called Castle Nuts, are the gold standard for high-vibration environments where fastener security is non-negotiable. Engineered with precision-cut slots on the top, these nuts are designed to work in tandem with a cotter pin or safety wire. Once tightened, the pin passes through the bolt’s hole and the nut’s slots, physically preventing the nut from backing off.
As a professional slotted nut manufacturer, we provide both DIN 935 (Standard Height) and DIN 937 (Thin Series) to meet diverse engineering requirements. From small M8 automotive nuts to massive M64 industrial locking nuts, our products ensure the structural integrity of rotating shafts and critical axles.
- Fail-Safe Locking: Provides a mechanical lock that cannot be vibrated loose, far superior to standard nylon insert nuts in heavy-duty use.
- High-Strength Grades: Available in Grade 8.8 and 10.9 Carbon Steel for high-load applications and SS316 for marine environments.
- Precision Slotting: Slots are perfectly centered to ensure easy alignment with the bolt hole, reducing installation time.
- Standardized Dimensions: Fully compliant with DIN 935, DIN 937, and ISO 7035 for global compatibility.
| Thread Size | Pitch (mm) | Width Across Flats (s) | Total Height (h) |
|---|---|---|---|
| M10 | 1.5 mm | 17 mm | 12 mm |
| M12 | 1.75 mm | 19 mm | 15 mm |
| M16 | 2.0 mm | 24 mm | 19 mm |
| M20 | 2.5 mm | 30 mm | 22 mm |
| M24 | 3.0 mm | 36 mm | 27 mm |
- Automotive Industry: Securing wheel bearings, ball joints, and steering linkages.
- Railway & Transit: High-torque locking in bogie assemblies and track switches.
- Aerospace: Used in landing gear and engine mounts where thermal expansion and vibration occur.
- Heavy Machinery: Essential for excavators, cranes, and agricultural harvesters.
- Tighten the slotted nut to the recommended torque specification.
- If the slots do not align with the bolt hole, tighten slightly further (never loosen) until the next slot aligns.
- Insert a cotter pin through the slot and the hole in the bolt.
- Bend the ends of the cotter pin around the nut or bolt to lock it permanently.
A: DIN 935 is the standard “thick” slotted nut, while DIN 937 is the “thin” or “flat” version used where space or weight is limited.
Q: Do you provide fine-pitch threads for M30 slotted nuts?
A: Yes, we offer M30x1.5 and M30x2.0 fine-pitch options for high-precision bearing adjustments.
Partner with a Leading M6-M64 Slotted Nut Factory
Seeking bulk DIN 935 or DIN 937 slotted nuts with reliable quality and fast delivery? We provide ISO 9001 certified fasteners for global markets. Contact us today for a free quote and technical catalog!












