Stainless Steel Hex Socket Screws | Custom Socket Head Cap Screws
Custom stainless steel hex socket screws manufactured to specified dimensions, thread requirements, material grades and surface finishes for industrial equipment, machinery, automotive and general assembly applications. Also referenced as socket head cap screws (SHCS) or hexagon socket head cap screws.
Key Specifications
| Specification | Available options |
|---|---|
| Product type | Hex socket screw / socket head cap screw |
| Head style | Socket head, or customer-specified geometry |
| Material | 304 (A2), 316 / 316L (A4), other specified grade |
| Thread | Metric or inch, coarse or fine where applicable |
| Size | Standard range or to customer drawing |
| Drive | Internal hex, matched to screw dimensions |
| Finish | Plain, passivation, or other specified treatment |
| Manufacturing | Cold heading / thread rolling for standard volumes; CNC and other processes for custom geometry |
| Production volume | Prototype, small batch and production |
| Packaging | Bulk, labeled or customer-specified |
Options describe what can be supplied against an agreed drawing or standard, not a guarantee that every combination is stocked. Quantities, grades and finishes are confirmed at quotation.
What Are Stainless Steel Hex Socket Screws?
Stainless steel hex socket screws are fasteners with an internal hexagonal drive that is installed with an Allen key or hex driver. The socket-head design provides a relatively compact head profile and is commonly used where fastening strength, accessibility and limited installation space matter.
The fastener has four functional parts: the head with the recessed hex socket, the shoulder beneath the head, the threaded shank, and the bearing surface that clamps the joint. Because the drive is internal, the screw can be tightened where a side wall would block an external wrench.
Stainless Steel Hex Socket Screw Specifications
| Specification | Details |
|---|---|
| Head style | Socket head / customer specified |
| Material | 304 / 316 / other specified grade |
| Thread | Metric / inch |
| Thread type | Coarse / fine where applicable |
| Size | Customer drawing / standard size range |
| Length | Customer specified |
| Drive size | Matched to screw dimensions |
| Finish | Plain / passivation / specified treatment |
| Manufacturing | Cold heading / CNC / combined processes depending on design |
| Packaging | Bulk / labeled / customer specified |
Standard-volume socket screws are typically produced by cold heading and thread rolling. Custom or non-standard screws — special lengths, diameters, head geometries, drives or materials — are manufactured by CNC machining and other suitable processes selected by geometry, material, quantity and dimensional requirements.
Standard Dimensions
The table below lists standard reference dimensions for metric socket head cap screws per ISO 4762 / DIN 912. Use it for selection; custom dimensions are produced to drawing.
| Thread | Head Ø (dk) | Head height (k) | Hex socket (s) | Typical lengths |
|---|---|---|---|---|
| M3 | 5.5 | 3.0 | 2.0 | 5–30 |
| M4 | 7.0 | 4.0 | 2.5 | 6–40 |
| M5 | 8.5 | 5.0 | 3.0 | 8–50 |
| M6 | 10.0 | 6.0 | 4.0 | 10–60 |
| M8 | 13.0 | 8.0 | 5.0 | 12–80 |
| M10 | 16.0 | 10.0 | 6.0 | 16–100 |
| M12 | 18.0 | 12.0 | 8.0 | 20–120 |
| Other | Custom diameters and lengths manufactured to drawing | |||
Values are standard reference figures for selection. Final dimensions are confirmed against your drawing or the named standard on the purchase order.
304 vs 316 Stainless Steel Socket Screws
304 Stainless Steel
- Corrosion resistance: good for most indoor and general environments
- Marine exposure: limited; application dependent
- Chemical exposure: good in many common applications
- Cost: usually lower
- Common use: general industrial and assembly fasteners
316 / 316L Stainless Steel
- Corrosion resistance: higher, especially in chloride environments
- Marine exposure: better suited
- Chemical exposure: better in many demanding environments
- Cost: usually higher
- Common use: marine, chemical, outdoor and washdown equipment
316 is not automatically the better choice for every application. Material selection should follow corrosion exposure, mechanical requirements, environment and cost targets.
Stainless Steel Grades Available
Fastener grades map to the base stainless grades as follows: A2 corresponds to 304, and A4 corresponds to 316 / 316L. We supply 304 (A2) and 316 / 316L (A4) as standard, and other customer-specified grades where the material and process are confirmed.
304 (A2)
General industrial, good corrosion resistance, lower cost.
316 / 316L (A4)
Higher corrosion resistance, marine and chemical service.
Other grades
Customer-specified grades confirmed per drawing and order.
Grades are listed only where supply is confirmed. We do not publish grades we cannot source or process to requirement.
Hex Socket Screw Standards
Where a standard is specified, screws are manufactured to its dimensional and thread requirements:
| Standard | Scope |
|---|---|
| ISO 4762 | Metric socket head cap screws |
| DIN 912 | Metric socket head cap screws (largely aligned with ISO 4762) |
| ASME B18.3 | Inch socket head cap screws where applicable |
| Customer drawing | Non-standard dimensions, heads, drives or threads |
We distinguish manufactured to a standard from certified compliant. Conformance to a named standard is confirmed through inspection documentation, not assumed from the product type.
Why Use Hex Socket Head Screws?
Compact head geometry
Fits spaces where a protruding head would interfere with surrounding parts.
Internal hex drive
Allows installation from limited side clearance using an Allen key or hex driver.
Recessed installation
Can sit flush or recessed into a counterbored hole depending on the joint design.
Machine assemblies
Suited to structural and mechanical fastening where repeatable torque matters.
Clean appearance
Plain stainless finish reads neutral in visible assemblies.
Tool engagement
Six-face hex contact spreads drive torque and resists cam-out.
Corrosion Resistance and Surface Treatment
Stainless steel resists corrosion through its passive chromium-rich surface. 304 covers most general environments; 316 / 316L performs better where chlorides, salt spray or chemicals are present. Surface condition also matters — contamination and embedded iron particles can compromise the passive layer.
Passivation of stainless steel is available to improve surface corrosion resistance and is described on our passivation page. Plain and other specified finishes are also offered.
Applications
Industrial machinery
Structural and panel fastening in equipment assemblies.
Automation equipment
Repeatable, space-saving fastening in fixtures and modules.
Automotive components
Non-visible and semi-visible joints in assemblies and brackets.
Electrical & electronics
Clean, non-magnetic-friendly fastening in enclosures and frames.
Marine equipment
316 grades for chloride-exposed and outdoor service.
Fixtures & jigs
Precision holding where flush heads reduce interference.
Stainless steel offers corrosion resistance where plain carbon-steel fasteners would need additional protection. Material grade should follow the actual service environment.
Standard and Custom Hex Socket Screws
Standard screws
Standard size, head, thread and material per ISO 4762 / DIN 912 or ASME B18.3. Suitable when an off-the-shelf geometry meets the design.
Custom screws
Non-standard length, special diameter, custom head geometry, special drive, custom thread, unusual material or drawing-specific requirements. Manufactured to drawing.
This page supports custom manufacturing to drawing rather than acting as a standard fastener catalogue. Custom work is where stainless hex socket screws are most often specified for a particular assembly.
Custom Screw Manufacturing to Drawing
Non-standard screws are produced by selecting the process that fits the part: CNC turning and milling for prototypes and lower volumes with tight or unusual geometry, and cold heading or combined processes where the volume and shape suit. The choice follows geometry, material, quantity and tolerances — not a single default method.
Related capabilities: stainless steel CNC machining, CNC turning services and custom CNC parts.
Quality Control for Stainless Steel Socket Screws
Incoming material
- Grade verification
- Material certificate where required
Dimensional inspection
- Head diameter and height
- Thread dimensions
- Overall length
- Socket geometry
Thread inspection
- Thread gauge / plug and ring gauges
- Pitch and profile verification
Surface inspection
- Burrs and scratches
- Contamination control
- Finish consistency
Packaging inspection
- Quantity check
- Label accuracy
- Lot identification
Documentation
- Material certificate on request
- Dimensional report on request
- Inspection report on request
Material certificates, dimensional reports and inspection reports are available on request and confirmed per order. Incoming material grade is verified before production begins.
Packaging and Identification
Screws are supplied in bulk, in sealed bags, or in labeled boxes per customer requirement. Lot identification and labels support traceability from incoming material to shipped parts.
How to Request a Custom Screw Quote
Send the following so we can review the part and recommend material, process and inspection:
- Thread size — metric or inch, coarse or fine
- Thread length and overall length
- Head diameter and head height
- Drive size — internal hex dimension
- Material grade — 304 (A2), 316 / 316L (A4) or specified
- Finish — plain, passivation or other
- Quantity — prototype, small batch or production
- Standard or drawing — named standard, or 2D / 3D file
If a full drawing is not yet available, a sample or a dimensional specification can support initial review where applicable.
Frequently Asked Questions
They fasten machinery, automation equipment, automotive components, electrical and electronic assemblies, marine equipment, and fixtures or jigs where a compact head and internal hex drive suit limited installation space.
A hex socket screw uses an internal hexagonal drive installed with an Allen key or hex driver, allowing side access and a low head profile. A Phillips screw uses a cross recess driven by a screwdriver and generally sits proud of the surface.
316 offers higher corrosion resistance, especially in chloride and marine environments, but usually costs more. 304 suits most general industrial applications. The right choice follows corrosion exposure, mechanical needs and cost, not a universal ranking.
Common standards are ISO 4762 and DIN 912 for metric screws and ASME B18.3 for inch sizes. Screws can also be made to a customer drawing. Compliance with a named standard is confirmed by inspection documentation, not assumed.
Yes. Non-standard lengths, diameters, head geometries, drives, threads or materials are manufactured to drawing using CNC machining and other suitable processes selected by geometry, material, quantity and tolerances.
Yes. Send the 2D drawing or 3D model with thread size, lengths, head dimensions, drive size, material grade, finish and quantity. A sample or dimensional specification can support initial review where a full drawing is not yet available.
Standard metric sizes from M3 to M12 follow ISO 4762 reference dimensions; other sizes and custom dimensions are produced to drawing. Available lengths depend on diameter and order requirements.
Yes. Passivation is available to improve surface corrosion resistance and is described on our stainless steel passivation page. Plain and other specified finishes are also offered.
Material certificates, dimensional reports and inspection reports are available on request and confirmed per order. Incoming material grade is verified before production.
Minimum quantity depends on material, geometry, process and finish. Prototypes and small batches are supported; confirm the exact MOQ when submitting drawings for review.
Request a Stainless Steel Screw Quote
Send your drawing or dimensional specification. Our engineering team will review the part and recommend the right material, process and inspection for standard or custom hex socket screws.