ISO 4028 Dog Point Hex Socket Set Screws
ISO 4028 hex socket set screws with dog point, M1.6 to M24 — the pilot-point set screw that rides a groove for parts removed often — with the full collected 13-size table including short and long dog point z and short/long key engagement.
Last updated: 2026-11
Specifications
The dog point of ISO 4028 is a cylindrical pilot turned on the end of the screw, and it solves a specific assembly problem: a part that must be removed and refitted without losing its register. The pilot rides in a matching groove or hole, so the collar or gear slides off and back on in the same rotational position — nothing to re-index. The collected table gives the full series M1.6 to M24 with both variants the standard allows: short dog point and long dog point, each tabulated as z max/min, alongside pitch P, pilot diameter d p (max/min), socket across-corners e min, key width s, and key engagement t min again split short screw/long screw. Choose the short dog where the mating groove is shallow or the screw length is tight; the long dog gives the pilot more guidance. The dog point is the least damaging of the locating points to the mating surface — it contacts a machined groove, not a scar it cuts itself — which is why it dominates on shafts that are ground and finish-critical. For surface-bearing points see ISO 4026/4029 and for cone location see ISO 4027 on this site.
| Standard | ISO 4028 — hexagon socket set screws with dog point |
|---|---|
| Series | M1.6 – M24 (13 sizes tabulated) |
| Tabulated geometry | Per size: pitch P, dog point pilot diameter d p max/min, socket across-corners e min, key width s nominal/max/min, dog point length z for short and long variants (max/min), key engagement t min for short and long screws |
| Point style | Dog point — cylindrical pilot riding a machined groove; repeatable registration for parts removed often, minimal mating-surface damage |
| Family note | Point-style sibling of ISO 4026 flat, ISO 4027 cone and ISO 4029 cup; metric counterpart of the DIN 915 line |
| Materials / strength | Not tabulated by the collected specification — per RFQ (property class and stainless grade per drawing callout) |
| Nominal thread | P — pitch (mm) | d p max (mm) | d p min (mm) | e min (mm) | s nominal (mm) | s max (mm) | s min (mm) | z — short dog point max (mm) | z — short dog point min (mm) | z — long dog point max (mm) | z — long dog point min (mm) | t min — short screw (mm) | t min — long screw (mm) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M1.6 | 0.35 | 0.8 | 0.55 | 0.809 | 0.7 | 0.724 | 0.71 | 0.65 | 0.4 | 1.05 | 0.8 | 0.7 | 1.5 |
| M2 | 0.4 | 1 | 0.75 | 1.011 | 0.9 | 0.913 | 0.887 | 0.75 | 0.5 | 1.25 | 1 | 0.8 | 1.7 |
| M2.5 | 0.45 | 1.5 | 1.25 | 1.454 | 1.3 | 1.3 | 1.275 | 0.88 | 0.63 | 1.5 | 1.25 | 1.2 | 2 |
| M3 | 0.5 | 2 | 1.75 | 1.733 | 1.5 | 1.58 | 1.52 | 1 | 0.75 | 1.75 | 1.5 | 1.2 | 2 |
| M4 | 0.7 | 2.5 | 2.25 | 2.303 | 2 | 2.08 | 2.02 | 1.25 | 1 | 2.25 | 2 | 1.5 | 2.5 |
| M5 | 0.8 | 3.5 | 3.2 | 2.873 | 2.5 | 2.58 | 2.52 | 1.5 | 1.25 | 2.75 | 2.5 | 2 | 3 |
| M6 | 1 | 4 | 3.7 | 3.443 | 3 | 3.08 | 3.02 | 1.75 | 1.5 | 3.25 | 3 | 2 | 3.5 |
| M8 | 1.25 | 5.5 | 5.2 | 4.583 | 4 | 4.095 | 4.02 | 2.25 | 2 | 4.3 | 4 | 3 | 5 |
| M10 | 1.5 | 7 | 6.64 | 5.723 | 5 | 5.14 | 5.02 | 2.75 | 2.5 | 5.3 | 5 | 4 | 6 |
| M12 | 1.75 | 8.5 | 8.14 | 6.863 | 6 | 6.14 | 6.02 | 3.25 | 3 | 6.3 | 6 | 4.8 | 8 |
| M16 | 2 | 12 | 11.57 | 9.149 | 8 | 8.175 | 8.025 | 4.3 | 4 | 8.36 | 8 | 6.4 | 10 |
| M20 | 2.5 | 15 | 14.57 | 11.429 | 10 | 10.175 | 10.025 | 5.3 | 5 | 10.36 | 10 | 8 | 12 |
| M24 | 3 | 18 | 17.57 | 13.716 | 12 | 12.212 | 12.032 | 6.3 | 6 | 12.43 | 12 | 10 | 15 |
| Nominal size | Thread pitch (mm) | D max — body dia (mm) | H nom — short dog point length (mm) | H nom — long dog point length (mm) | L preferred min — dog point (mm) | V max — dog point dia (mm) |
|---|---|---|---|---|---|---|
| M3 | 0.5 | 2.10 | 0.75 | 1.5 | 5.0 | 2.00 |
| M4 | 0.7 | 2.75 | 1.00 | 2.0 | 5.0 | 2.50 |
| M5 | 0.8 | 3.70 | 1.25 | 2.5 | 6.0 | 3.50 |
| M6 | 1.00 | 4.25 | 1.50 | 3.0 | 6.0 | 4.00 |
| M8 | 1.25 | 6.00 | 2.00 | 4.0 | 8.0 | 5.50 |
| M10 | 1.50 | 7.40 | 2.50 | 5.0 | 8.0 | 7.00 |
| M12 | 1.75 | 8.60 | 3.00 | 6.0 | 12.0 | 8.50 |
| M16 | 2.00 | 12.35 | 4.00 | 8.0 | 16.0 | 12.00 |
| M20 | 2.50 | 16.00 | 5.00 | 10.0 | 20.0 | 15.00 |
| M24 | 3.00 | 18.95 | 6.00 | 12.0 | 22.0 | 18.00 |
Materials
- Material, property class and finish specified per RFQ — the collected specification table covers geometry only
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (ISO 4028 Dog Point Hex Socket Set Screws) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
Short dog point or long dog point?
The two z variants in the table exist because the mating groove depth is a design choice. A long dog engages more of the groove and guides better on reassembly, but it needs the groove to match — on a short hub or a screw length already at its limit the extra pilot length will bottom out before the screw is tight. The short dog is the default for shallow grooves and tight envelopes; pick the long dog when the part sees frequent removal and the groove was cut for it. Both variants share the same pilot diameter d p in each size.
What should an RFQ for ISO 4028 set screws state?
The designation (ISO 4028), thread size, length, dog point variant (short or long), material and property class or stainless grade, finish, and quantity per size. The z and t columns in the table let the receiving inspection check the pilot against the mating groove; commercial terms follow the quotation.
What is the MOQ and lead time for these screws?
Minimum order quantity is 10,000 pieces per item. Stocked sizes ship in 3–7 days; non-stock diameters, lengths or finishes are quoted with a confirmed schedule. Common sizes in this designation are widely stocked — confirm the exact schedule against quantity and size mix at quotation.
Related knowledge
- Thread-Forming vs Thread-Cutting vs Thread-Rolling Self-Tapping Screws: What the Evidence Settles on Base Material
- Screw Family Selection by Base Material: Wood, Machine and Self-Tapping Threads, Engagement and Coating
- Hex Bolts vs Socket Head Cap Screws: What the Evidence Settles on Strength, Clearance and Cost
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support