DIN913 Hex Socket Flat Point Set Screw Assortment – M3–M10 Black Steel & 304 Stainless Steel Mix

DIN913 flat point set screws (grub screws) are the correct choice when shaft marking must be minimized or eliminated. Unlike cup point screws (DIN916) which bite into the shaft surface, the flat point contacts the shaft with a smooth, flat face — relying on friction and clamping force rather than mechanical penetration. This makes flat point set screws essential for hardened shafts (where cup points cannot penetrate), polished shafts (where surface finish must be preserved), and precision positioning applications where the shaft must be repositioned without damage.

Key Specifications

• Standard: DIN913 / ISO 4026 (hex socket flat point set screw)
• Materials: Black oxide alloy steel (Grade 45H) + 304 stainless steel (A2) — mixed assortment
• Drive: Internal hex (Allen key)
• Point Style: Flat point — smooth flat face, zero shaft penetration
• Sizes: M3, M4, M5, M6, M8, M10 (multiple lengths per size)
• Thread: Metric coarse pitch
• Hex Key Sizes: M3=1.5mm, M4=2mm, M5=2.5mm, M6=3mm, M8=4mm, M10=5mm

Flat Point vs Cup Point vs Cone Point — When to Use Each

• Flat point (DIN913, this product): Zero shaft penetration. Relies on friction only. Use for: hardened shafts (HRC 40+) where cup points cannot bite; polished or ground shafts where surface finish must be preserved; applications requiring frequent repositioning without shaft damage; soft materials (aluminum, brass, plastic) where cup points would cause excessive damage.
• Cup point (DIN916): Shallow cup rim bites into shaft. Moderate holding force with minimal shaft damage. The most common general-purpose set screw. Use for steel shafts where occasional repositioning is acceptable.
• Cone point (DIN914): Deep penetration into a pre-drilled dimple. Maximum holding force. Permanent or semi-permanent applications only.
• Dog point (DIN915): Cylindrical stub locates into a drilled hole. Positive angular and axial location. Precision indexing applications.

What Questions Does This Product Answer?

• "Will flat point set screws mark my shaft?" — Minimal marking. The flat face distributes clamping force over a larger area than a cup or cone point, leaving only a slight compression mark rather than a gouge. On hardened shafts (HRC 40+), there is typically no visible marking at all.
• "What is the holding force of a flat point set screw vs cup point?" — Flat point holding force is approximately 60–70% of cup point at the same torque, because it relies on friction only (no mechanical bite). For high-torque applications, use cup point or add a second set screw at 90° to the first.
• "Can I use flat point set screws on a stainless steel shaft?" — Yes. Flat point is preferred on stainless shafts because stainless work-hardens under cup point penetration, making future removal difficult. The flat point avoids this work-hardening effect.
• "Why does this assortment include both black steel and stainless?" — Black oxide steel (Grade 45H) provides higher hardness and holding force for general mechanical applications. A2 stainless provides corrosion resistance for outdoor, marine, and food-contact applications. Having both in one kit covers the majority of use cases without ordering separately.

Typical Applications

• Precision machinery: Locking components on ground or hardened shafts where surface finish must be preserved
• Optical equipment: Lens tube locking, mirror mount adjustment, optical rail positioning
• CNC & machining: Dial indicator stem locking, measuring instrument mounting, fixture positioning
• Robotics: Servo horn locking on hardened output shafts, encoder disc positioning
• Soft material assemblies: Locking components on aluminum, brass, or plastic shafts where cup points would cause excessive damage

Package Contents

Assortment kit — M3–M10 DIN913 flat point set screws in black oxide steel and 304 stainless steel, multiple lengths per size, in labeled storage case.