Material
Carbon Steel
Type
Large knurled head
Size Range
M3–M12
Surface Finish
Zinc-Plated / Plain
Grade
Steel / A2 / A4
Standard
Knurled head
Packaging
Carton / Pallet
MOQ
1 piece (sample)
Precision Manufacturing, Batch After Batch
From cold-heading raw steel wire to heat-treated finished bolts, every step runs under strict in-house process control — ensuring the dimensional accuracy and strength grade printed on every head marking.
Product Overview
Application Scenarios
Hand-tighten thumb screws have a large knurled head that is turned by finger and thumb with no tool, for parts that are set, adjusted or removed often. The tall straight-knurled head gives a firm grip even with gloves or oily hands, and many carry a screwdriver slot as well for a final nip. They are used on machine guards and covers, jigs and fixtures, adjustable stops, electronic and instrument enclosures, camera and lab equipment, and 3D-printer and furniture fittings. Carbon steel is zinc-plated for indoor use; stainless A2 / A4 suits damp, outdoor, food and medical applications.
Installation Notes
Start the thread square by hand to avoid cross-threading, then run the screw down and nip it up with firm finger-and-thumb pressure on the knurled head — the knurl, not a tool, provides the grip. Where a slot is provided a light final turn with a screwdriver adds clamp without needing a wrench. Use a flat washer under the head to spread the load and protect the surface, and a spring washer where mild vibration is present. Thumb screws give a light-to-moderate clamp by hand, so use them for covers, guards and adjustable joints rather than high-load structural connections.
Material & Certification
Machined or cold-formed from carbon steel with a straight-knurled head and zinc-plated, with head and thread gauge-checked and every batch traceable to raw material certificates. Each lot passes dimensional inspection before packaging; EN 10204 3.1 material certificates are available on request.
Hand-Tighten Thumb Screw
Carbon Steel Thumb Screw · Knurled Head · Zinc-Plated
Dimensional Specifications
Typical Reference Dimensions — click a size to locate it below
| Thread Size | Head Dia dk (mm) | Head Height k (mm) | Length L (mm) |
|---|---|---|---|
| M3 | 10 | 5 | 6–20 |
| M4 | 12 | 6 | 8–25 |
| M5 | 16 | 8 | 8–30 |
| M6 | 20 | 10 | 10–40 |
| M8 | 24 | 12 | 12–50 |
| M10 | 28 | 14 | 16–60 |
| M12 | 32 | 16 | 20–60 |
Typical reference dimensions — this part is not covered by a fixed DIN/ISO dimensional standard and is made to your drawing. Contact us with your panel thickness, grip, length or head requirement for an exact specification sheet.
Applications
Construction
Steel structures, bridges, buildings, concrete anchors
Machinery
Heavy equipment, industrial machines, manufacturing
Infrastructure
Railways, towers, pipelines, power transmission
Automotive
Vehicle assembly, chassis, engine components
Trusted By Global Buyers
Factory-direct thumb screws exported to construction, machinery and infrastructure buyers across Europe, Africa, Asia and the Americas.