Knurled Head Captive Screws
Knurled Head Captive Screws are designed for applications where a fastening point needs to be operated by hand while the screw remains attached to the assembly. The knurled head provides a practical gripping surface, allowing the screw to be tightened or loosened without requiring a separate tool.
The waisted shank gives the screw its captive function. Once the screw is loosened, it remains retained in the panel or component instead of becoming a loose part. This makes the design particularly useful for equipment that is opened, adjusted, inspected, or serviced regularly. Manufactured according to GB/T 839-1988, these screws are available in metric sizes from M3 to M10. Carbon steel and stainless steel options can be supplied, together with different finishes, lengths, and other configurations according to the requirements of the assembly.
Specification:
Knurled Head Captive Screws are manufactured according to GB/T 839-1988, with metric sizes from M3 to M10. The standard defines the main dimensions of the screw, including the knurled head, waisted shank, thread, and overall length, providing consistent dimensions for production and assembly. We can supply these screws in carbon steel and stainless steel, including A1, A2, and A4 stainless steel options where applicable. Standard and customized surface finishes are available, and different lengths, thread lengths, materials, and other dimensions can be produced according to customer drawings or specific requirements.
| Item | Specification |
|---|---|
| Standard | GB839 |
| Size Range | M3-M10 |
| Thread | Metric |
| Thread Tolerance | 6g |
| Head Type | Knurled Head |
| Shank | Waisted Shank |
| Material | Carbon Steel,Stainless Steel |
| Surface | Zinc Plated, Bright Finish,Passivation |
| Property Class | 4.8,A1-50,A2-50/70 |
| Mechanical Property Standard | ISO898-1,ISO3506-1 |
| Inspection | Dimensions,Thread,Mechanical Property,Coating |
Dimension Chart of Knurled Head Captive Screws:
The dimensions of a captive screw need to be considered as a complete assembly rather than by thread size alone. The head diameter, head height, waisted shank, thread length, and overall length determine how the screw fits into the panel and how it functions after installation. GB/T 839-1988 covers metric sizes from M3 to M10. When selecting a size, the panel thickness, mounting hole, required thread engagement, and available space around the fastening point should be checked together.
For special panel thicknesses or assembly requirements, customized thread lengths, overall lengths, and other dimensions can be manufactured according to customer drawings.
| Mon | M3 | M4 | M5 | M6 | M8 | M10 |
| P | 0.5 | 0.7 | 0.8 | 1 | 1.25 | 1.5 |
| ds max | 2 | 2.8 | 3.5 | 4.5 | 5.5 | 7 |
| ds min | 1.86 | 2.66 | 3.32 | 4.32 | 5.32 | 6.78 |
| dk max | 5 | 8 | 9 | 11 | 14 | 17 |
| dk min | 4.82 | 7.78 | 8.78 | 10.73 | 13.73 | 16.73 |
| k max | 4.5 | 6.5 | 7 | 10 | 12 | 13.5 |
| k min | 4.32 | 6.32 | 6.78 | 9.64 | 11.57 | 13.07 |
| n min | 0.86 | 1.26 | 1.28 | 1.66 | 2.06 | 2.56 |
| n max | 1 | 1.51 | 1.51 | 1.91 | 2.31 | 2.81 |
| t min | 0.7 | 1 | 1.2 | 1.4 | 1.9 | 2.4 |
| r min | 0.1 | 0.2 | 1.2 | 1.4 | 1.9 | 2.4 |
| k1 | 1 | 1.5 | 1.5 | 2 | 2.5 | 2.5 |
- RELATED SCREWS LISTS:
- Stainless Steel DIN7976 Hexagon Head Tapping Screws
- Stainless Steel DIN7982 Cross Recessed Countersunk Head Tapping Screws
- Stainless Steel DIN7983 Cross Recessed Raised Countersunk Head Tapping Screws
- Stainless Steel DIN7985 Cross Recessed Raised Cheese Head Screws
- DIN7964E Stainless Steel Socket Head Cap Captive Screw
- Stainless Steel DIN964 Slotted Raised Countersunk Head Screws
- Stainless Steel DIN966 Cross Recessed Raised Countersunk Head Screws
- Stainless Steel DIN967 Cross Recessed Pan Head Screws with Collar
- Stainless Steel DIN968 Cross Recessed Pan Head Tapping Screws with Collar
- GB830 Stainless Steel Slotted Cheese Head Screws with Shoulder
- Stainless Steel GB831 Slotted Shoulder Screws
- Stainless Steel GB834 Knurled Thumb Screws
- Stainless Steel GB835 Knurled Screws
- Stainless Steel GB836Knurled Screws with Small Head
- Stainless Steel GB837 Slotted Pan Head Screws with Waisted Shank
- Nickel Plated Smooth Shank Single Shoulder Shelf Support Screw
- Nickel Plated Furniture Shelf Peg with Matching Knurled Nut
Application of Knurled Head Captive Screws:
Removable Panels and Covers
Knurled Head Captive Screws are well suited to removable panels, access covers, inspection plates, and equipment housings. The screw can be loosened for access while remaining attached to the panel, reducing the chance of losing small fasteners during maintenance.
Tool-Free Equipment Access
The knurled head makes the screw convenient for applications where operators need to open or close a component by hand. This is useful for covers and service points that are accessed regularly without requiring a screwdriver or other hand tool.
Service and Adjustment Points
These screws can also be used on adjustable components, guards, brackets, and serviceable assemblies where the fastening point may need to be opened repeatedly. The captive design keeps the fastener with the assembly, making subsequent reassembly simpler.