GB/T 73 specifies the dimensions and tolerances for slotted flat point set screw. The full dimensional table is reproduced below, followed by the DIN, ISO and ASME parts that match or supersede it.
- Standard
- GB/T 73
- Product
- Slotted Flat Point Set Screw — GB/T 73 / ISO 4766 (Series 038)
- Governing standards
- GB/T 73 / ISO 4766
Equivalence between national standards is dimensional, not always metallurgical. Check the property class separately when substituting.
The table below lists the dimensions catalogued for slotted flat point set screw under GB/T 73. The scope of GB/T 73 itself is not summarised here — where a figure matters, confirm it against the published document.
GB/T 73 — Scope
The table below lists the dimensions catalogued for slotted flat point set screw — gb/t 73 / iso 4766 (series 038) under GB/T 73. The scope of GB/T 73 itself is not summarised here — where a figure matters, confirm it against the published document.
Tolerance & Product Grades
Product grade is a concept from dimensional fastener standards and does not apply to GB/T 73. Tolerances for this part are the limits shown against each dimension in the table.
Dimensions Specified by GB/T 73
| Size | Pitch (mm) | Length L (mm) | Hex socket s (mm) | Engagement depth t min (mm) | Point diameter dp (mm) | Reference standard |
|---|
| M3 | 0.5 | 6 | 1.5 | 1.4 | 2.0 | ISO 4026-4029 / GB/T 77-79 |
| M4 | 0.7 | 6 | 2.0 | 2.0 | 2.5 | ISO 4026-4029 / GB/T 77-79 |
| M5 | 0.8 | 7 | 2.5 | 2.5 | 3.5 | ISO 4026-4029 / GB/T 77-79 |
| M6 | 1.0 | 9 | 3.0 | 3.0 | 4.0 | ISO 4026-4029 / GB/T 77-79 |
| M8 | 1.25 | 12 | 4.0 | 4.0 | 5.5 | ISO 4026-4029 / GB/T 77-79 |
| M10 | 1.5 | 15 | 5.0 | 5.0 | 7.0 | ISO 4026-4029 / GB/T 77-79 |
| M12 | 1.75 | 18 | 6.0 | 6.0 | 8.5 | ISO 4026-4029 / GB/T 77-79 |
| M16 | 2.0 | 24 | 8.0 | 8.0 | 12.0 | ISO 4026-4029 / GB/T 77-79 |
| M20 | 2.5 | 30 | 10.0 | 10.0 | 15.0 | ISO 4026-4029 / GB/T 77-79 |
| M24 | 3.0 | 36 | 12.0 | 12.0 | 18.0 | ISO 4026-4029 / GB/T 77-79 |
Companion Standards
A complete specification for slotted flat point set screw — gb/t 73 / iso 4766 (series 038) normally cites several documents: one for the geometry, one for the material or mechanical properties, and one for the finish. GB/T 73 is one of them, not all of them.
When to Specify GB/T 73
Choose GB/T 73 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for slotted flat point set screw — gb/t 73 / iso 4766 (series 038).
Custom manufacturing · Made to drawing
Need a screw to this standard in a non-standard size?
Parts built to GB T 73 are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
Custom screw manufacturingSend a drawing
Applications & Industries
What Slotted Flat Point Set Screw are specified for, industry by industry. Stocked from M3 to M24.
Industries that specify Slotted Flat Point Set Screw
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Steel fabrication
Bolted connections in frames, enclosures, walkways and weldments, on the bench and on site.
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Energy & infrastructure
Tower, pipework, switchgear and plant fixings specified for long service life and inspectable joints.
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Maintenance & MRO
Stocked replacements matched to an existing property class, thread and finish.
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Food, pharma & cleanroom
Stainless assemblies that are washed down, where the finish matters as much as the strength.
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Machine building & OEM
The default fastener on production equipment: covers, brackets, motor mounts and sub-assemblies tightened to a specified torque.
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Automotive & transport
Chassis, driveline and body fixings that see vibration and are assembled to a controlled preload.
Typical applications
- assemblies that are dismantled for service and re-torqued
- joints where the property class is stated on the drawing
- clamping two machined faces to a calculated preload
- bolting brackets, motors and gearboxes to a frame
Service conditions to specify against
- Marine and coastal
- Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- High load
- Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
- Torque and preload
- The joint is designed around bolt tension, so lubrication, coating and the friction coefficient all change the torque figure — state them together.
Where to use something else
- Do not use a machine thread into unthreaded sheet or timber; use a tapping screw, rivet nut or insert made for that parent material.
Need help matching Slotted Flat Point Set Screw to your application? Send the assembly, the load and the environment with your enquiry and we will specify the size, material and finish against them.
