DIN 653 Flat Knurled Screws

DIN 653 flat knurled screws are low-profile hand-tightening fasteners with a round knurled head and external metric thread. They are also commonly described as flat knurled thumb screws or low-type knurled screws. The knurled head provides a gripping surface for tightening and loosening by hand without a screwdriver or wrench. DIN 653 defines the dimensional characteristics of this flat-type design and distinguishes it from taller knurled thumb screws such as DIN 464.

The low head profile makes DIN 653 screws useful where a conventional high knurled head would interfere with adjacent components or available clearance. Typical applications include machinery, equipment panels, instrument assemblies, fixtures, covers, control mechanisms, and other components that require frequent manual adjustment or removal. The screw can be operated without a separate driving tool, making it practical for access points that need to be opened or adjusted during routine operation or maintenance.

DIN 653 covers metric thread sizes from M1 to M10, while M3 to M10 are common commercial sizes in industrial supply. Standardized dimensions include the thread diameter, head diameter, head height, and screw length, allowing buyers to specify the product according to established dimensional requirements. Steel versions are commonly supplied in property class 5, while stainless steel and brass versions are also found in the market. DIN 653 also permits surface finishes such as plain, blackened, and zinc-plated versions depending on material and supply specification.