For DIYers, hobbyists, and professional machinists who value precise, dependable fasteners, these USED Hexagon flat-end setting screws in M4x4 size with carbon steel construction are a smart choice. Designed to lock components in place with a flush seating, they combine robust torsion resistance with a compact footprint — ideal for tight spaces where a standard screw would protrude or misalign parts.

• Size and threading: M4 x 4 mm — standard metric thread compatible with common holes and components.
• End style: Flat end provides flush seating against the mating surface to keep assemblies true and aligned.
• Drive type: Hex (internal hex) drive for secure tightening with a correctly sized Allen key; helps prevent cam-out in tight spots.
• Material: Carbon steel offers solid strength and durability for everyday mechanical applications.
• Condition: USED — visible signs of prior use; functional integrity should be checked before critical load use.
• Ideal uses: securing gears, pulleys, collars, or fixtures in machinery, jigs, 3D printers, CNC setups, or cabinetry where a slim, flush-fastener is needed.
• Installation tips: Clean threads before installation, avoid over-tightening to prevent thread damage, and consider a light thread-lubing agent in high-vibration environments for longevity.

What makes these screws stand out is the combination of a flat-end design and a compact M4x4 footprint, which lets you space components accurately and maintain clean, professional-looking assemblies. If you’re outfitting a project that demands reliable clamping without visible screw heads or protrusions, these carbon steel set screws deliver consistent performance at a value-friendly price.