Home » DIN 915 / ISO 4028 Socket Set Screw with Dog Point A2 Stainless

DIN 915 / ISO 4028 Socket Set Screw with Dog Point A2 Stainless

DIN 915 / ISO 4028 — Socket Set Screw with Dog Point | A2 Stainless Steel | Bright Passivated

FULLERKREG DIN 915 / ISO 4028 socket set screws (grub screws) with dog point are manufactured to full DIN and ISO dimensional standards in A2 stainless steel (SUS 304) with a bright passivated surface finish. The precision-ground cylindrical dog point provides positive mechanical location and engagement, making these set screws the definitive choice for precision positioning, indexing, and shaft-locking applications in corrosion-resistant environments — including food processing, pharmaceutical, laboratory, marine, and general industrial use.

Product Specifications

Parameter Detail
Standard DIN 915 / ISO 4028
Type Socket Set Screw (Grub Screw) — Dog Point
Drive Hexagon Socket (Hex Allen Key)
Material A2 Stainless Steel (SUS 304 / 1.4305)
Property Class A2-70 (per ISO 3506-3)
Surface Treatment Bright Passivated (Electrochemical Passivation)
Thread Metric Coarse Thread (ISO 68-1)
Thread Tolerance 6H (internal) / 6g (external) per ISO 965
Tensile Strength Min. 700 MPa (A2-70)
Hardness Max. 220 HV (Vickers)
Size Range M3 — M20
Length Range 5 mm — 60 mm (size-dependent)
Point Type Dog Point (Extended Cylindrical Pin)
Head Type Fully Threaded, Headless (Grub)
RoHS Compliant Yes

Key Dimensions (DIN 915 / ISO 4028)

Thread (d) Hex Key (s) Dog Point Dia. (dp) h8 Dog Point Length (t) min. Common Lengths (l)
M3 1.5 mm 2.0 mm 1.5 mm 5, 6, 8, 10, 12 mm
M4 2.0 mm 2.5 mm 2.0 mm 6, 8, 10, 12, 16 mm
M5 2.5 mm 3.5 mm 2.5 mm 8, 10, 12, 16, 20 mm
M6 3.0 mm 4.0 mm 3.0 mm 8, 10, 12, 16, 20, 25 mm
M8 4.0 mm 5.5 mm 4.0 mm 10, 12, 16, 20, 25, 30 mm
M10 5.0 mm 7.0 mm 5.0 mm 12, 16, 20, 25, 30, 40 mm
M12 6.0 mm 8.5 mm 6.0 mm 16, 20, 25, 30, 40, 50 mm
M16 8.0 mm 11.0 mm 8.0 mm 20, 25, 30, 40, 50, 60 mm
M20 10.0 mm 14.0 mm 10.0 mm 25, 30, 40, 50, 60 mm

Dog point diameter (dp) is ground to h8 tolerance per DIN 915 / ISO 4028 for precise hole engagement. All dimensions per DIN 915 / ISO 4028. Consult FULLERKREG datasheet or contact us for full tolerance tables.

Dog Point — Design & Function

The dog point is a precision-ground cylindrical pin extension that protrudes beyond the threaded body of the set screw. Unlike friction-only point types (flat, cup, cone), the dog point engages a matching hole or slot in the mating shaft or component, providing positive mechanical location independent of clamping force alone.

Key Functional Advantages

  • Positive axial location — the dog point engages a drilled hole in the shaft, preventing axial movement regardless of vibration or load reversal
  • Positive rotational location — when engaged in a hole or slot, prevents shaft rotation relative to the hub without relying solely on friction
  • Repeatable repositioning — the set screw can be removed and reinstalled with the component returning to exactly the same position; ideal for indexed or adjustable assemblies
  • No shaft damage — the cylindrical dog point engages a pre-drilled hole cleanly; no marring, indenting, or deformation of the shaft surface
  • Keyway-free design — eliminates the need for a keyway on the shaft, simplifying shaft machining and reducing stress concentrations
  • Corrosion-resistant engagement — A2 stainless construction ensures the dog point itself does not corrode or seize in the shaft hole, maintaining clean disassembly in service environments

Dog Point vs. Other Set Screw Point Types

Point Type Standard Holding Mechanism Repositionable Shaft Damage Best For
Flat Point DIN 913 / ISO 4026 Friction only Yes None Non-marring, frequent adjustment
Cup Point DIN 916 / ISO 4029 Friction + indent Limited Circular indent Permanent locking, soft shafts
Cone Point DIN 914 / ISO 4027 Friction + deep indent No Deep indent Permanent location, V-groove
Dog Point DIN 915 / ISO 4028 Friction + positive pin engagement Yes None (pre-drilled hole) Precision location, indexing, keyway-free
Oval Point ISO 4026 variant Friction only Yes Minimal Curved surfaces, pivot points

Material — A2 Stainless Steel (SUS 304)

Chemical Composition

  • Chromium (Cr): 17.5 – 19.5%
  • Nickel (Ni): 8.0 – 10.5%
  • Carbon (C): ≤ 0.08%
  • Manganese (Mn): ≤ 2.0%
  • Silicon (Si): ≤ 1.0%
  • Type: Austenitic stainless steel

Mechanical Properties — A2-70 (per ISO 3506-3)

Property Value
Tensile Strength (Rm) Min. 700 MPa
Proof Load Stress (Sp) Min. 450 MPa
Hardness Max. 220 HV (Vickers)
Magnetic Non-magnetic (annealed state)
Temperature Range −196°C to +300°C continuous

Corrosion Resistance

  • Excellent resistance to atmospheric corrosion, humidity, and moisture
  • Resistant to mild acids, alkalis, and most organic chemicals
  • Suitable for food contact and hygienic applications
  • Not recommended for prolonged exposure to chloride-rich environments (seawater, salt spray) — consider A4 (SUS 316) for such conditions

Surface Finish — Bright Passivated

  • Process: Electrochemical passivation — removes free iron and surface contaminants from the stainless steel surface
  • Effect: Restores and enhances the natural chromium oxide passive layer, maximizing the inherent corrosion resistance of A2 stainless steel
  • Appearance: Bright, clean, silver finish — no coating thickness added, no dimensional change; dog point h8 tolerance is fully maintained
  • Compliant with: ASTM A967 / ISO 16048 passivation standards
  • No hydrogen embrittlement risk: No electroplating involved
  • Hygienic: Smooth, non-porous surface with no coating to flake or contaminate; suitable for food, pharmaceutical, and clean-room environments

Typical Applications

The combination of A2 stainless steel, bright passivated finish, and dog point positive engagement makes these set screws the preferred choice for precision applications in corrosion-resistant environments:

  • Food & Beverage Processing: Locating conveyor components, agitator shafts, and filling machine parts where hygiene, wash-down resistance, and non-contamination are required
  • Pharmaceutical & Medical: Precision location of components in clean-room equipment, sterilizable assemblies, and laboratory instruments requiring non-magnetic, non-reactive fasteners
  • Laboratory & Scientific Instruments: Indexing and positioning optical components, sample stages, and measurement fixtures requiring repeatable, corrosion-free location
  • Marine & Coastal (Splash Zone): Locating components in deck hardware, rigging, and marine equipment exposed to salt spray and humidity
  • Chemical Processing: Securing and locating components in equipment handling mild acids, alkalis, and process fluids
  • Electronics & Automation: Non-magnetic location of encoder discs, servo motor shafts, and sensor components in sensitive assemblies
  • General Precision Machinery: Securing pulleys, gears, couplings, and collars to shafts at precise axial positions with repeatable disassembly
  • Indexing & Detent Mechanisms: Engaging indexing holes in rotary tables, dividing heads, and adjustable fixtures for repeatable angular positioning

Installation Guidelines

Shaft Hole Preparation

  • Drill a hole in the shaft at the desired location to match the dog point diameter (dp) — refer to the dimension table above
  • Recommended hole tolerance: H8 (clearance fit with dog point h8) for easy engagement and removal; H7 for tighter location with minimal play
  • Hole depth should be at least equal to the dog point length (t) plus 0.5 mm clearance at the bottom
  • Deburr the hole entrance to prevent galling on the dog point during engagement
  • For indexed applications, use a jig or dividing head to ensure hole positions are accurately located

Installation Procedure

  • Thread engagement: Minimum engagement length = 1× nominal diameter (e.g., M6 requires min. 6 mm engagement)
  • Alignment: Align the dog point with the shaft hole before tightening; partial engagement will damage the dog point and hole
  • Tightening torque: Use a calibrated torque wrench — refer to the torque table below
  • Anti-galling lubrication: Apply molybdenum disulfide paste or PTFE-based lubricant to threads before installation; stainless-to-stainless assemblies are particularly susceptible to galling — lubrication is essential
  • Hex key: Use the correct size hex key (Allen key) — see dimension table above
  • Locking: For vibration-prone applications, apply medium-strength thread-locking adhesive to the threads before installation
  • Do not over-torque: A2 stainless has lower hardness than alloy steel; over-torquing risks thread stripping or socket rounding

Recommended Tightening Torques (A2-70, MoS₂ Lubricated)

Thread Torque (N·m) — Reference
M3 0.30 N·m
M4 0.70 N·m
M5 1.40 N·m
M6 2.40 N·m
M8 5.80 N·m
M10 11.5 N·m
M12 20.0 N·m
M16 49.0 N·m
M20 96.0 N·m

Reference values for MoS₂-lubricated A2-70 stainless steel set screws. For dry installation, increase values by approximately 15–20%. Always verify with your engineering team for safety-critical applications. Note: lubrication is strongly recommended for stainless-to-stainless assemblies to prevent galling.

Standards & Compliance

  • DIN 915 — Socket set screws with hexagon socket and long dog point
  • ISO 4028 — Hexagon socket set screws with long dog point
  • ISO 3506-3 — Mechanical properties of corrosion-resistant stainless steel fasteners (set screws); A2-70 property class
  • DIN 267-11 — Technical delivery conditions for fasteners; stainless steel property classes
  • ISO 965-1 — Metric screw thread tolerances
  • ASTM A967 / ISO 16048 — Passivation of stainless steel
  • RoHS 2011/65/EU — Restriction of hazardous substances compliant

Packaging & Ordering

  • Available in standard retail packs, engineering bulk packs, and full-box quantities
  • Custom quantity packaging available for OEM and wholesale customers
  • Each pack labeled with: Part number, Thread size × Length, Material (A2), Standard (DIN 915 / ISO 4028), Surface (Bright Passivated), Quantity
  • Bulk orders: contact FULLERKREG for volume pricing and lead times

Quality Assurance

  • 100% dimensional inspection on critical sizes per DIN 915 / ISO 4028, including dog point diameter (h8 tolerance)
  • Material certification (Mill Test Certificate) available on request — confirms A2 / SUS 304 composition
  • Hardness and tensile testing per ISO 3506-3 batch requirements
  • Thread gauge inspection (Go/No-Go) per ISO 965
  • Dog point concentricity and surface finish verified on sample basis per batch
  • Salt spray corrosion testing available for qualification batches
  • Traceability: heat number and batch records maintained

Frequently Asked Questions

Q: What is the difference between DIN 915 and ISO 4028?
A: DIN 915 and ISO 4028 are technically equivalent standards for socket set screws with long dog point. DIN 915 is the German standard; ISO 4028 is the international equivalent. Dimensions and tolerances are identical — parts are fully interchangeable.

Q: What is a dog point and how does it work?
A: A dog point is a precision-ground cylindrical pin extension beyond the threaded body of the set screw. It engages a pre-drilled hole in the mating shaft, providing positive mechanical location — both axially and rotationally — independent of friction alone. The assembly can be disassembled and reassembled to exactly the same position, making it ideal for indexed and adjustable applications.

Q: What hole size should I drill in the shaft for the dog point?
A: The dog point is manufactured to h8 tolerance. For standard engagement, drill the shaft hole to H8 tolerance (clearance fit) for easy assembly and disassembly. For tighter location with minimal play, use H7. Refer to the dimension table above for the dog point diameter (dp) for each thread size.

Q: Why is lubrication especially important for A2 stainless set screws?
A: Stainless steel is particularly susceptible to galling — a form of adhesive wear where the threads seize and weld together during tightening. This is especially common in stainless-to-stainless assemblies. Applying an anti-galling lubricant (MoS₂ paste or PTFE compound) before installation is essential to prevent galling and ensure accurate torque application.

Q: Can A2 stainless dog point set screws be used in food processing equipment?
A: Yes. A2 (SUS 304) stainless steel is widely accepted for food contact applications. The bright passivated finish provides a smooth, non-porous, non-contaminating surface. For wash-down environments with chloride-containing cleaning agents, consider A4 (SUS 316) for enhanced chloride resistance. Contact FULLERKREG for A4 options.

Q: Can the dog point set screw replace a key-and-keyway connection?
A: Yes, in many applications. The dog point engaging a drilled hole in the shaft provides both axial and rotational location without requiring a keyway. This simplifies shaft manufacturing and allows the connection point to be repositioned. For very high torque transmission, consult your engineering team to verify the dog point engagement is sufficient for the applied loads.

Q: What hex key (Allen key) size do I need?
A: Refer to the dimension table above. Examples: M3 requires a 1.5 mm hex key; M6 requires a 3.0 mm hex key; M10 requires a 5.0 mm hex key.

Q: Are these RoHS compliant?
A: Yes. FULLERKREG A2 stainless dog point set screws are manufactured without restricted hazardous substances and are RoHS 2011/65/EU compliant.

Q: Can I get a material test certificate (MTC)?
A: Yes. FULLERKREG provides Mill Test Certificates on request, confirming the A2 / SUS 304 stainless steel chemical composition.

FULLERKREG — Precision Fasteners to DIN / ISO Standards. For technical support, custom sizes, or bulk quotations, please contact our engineering team.

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