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+86 13143444311
Email：sst@szsst88.com
Fax：+0086-755-27322278
Address：Building 9, First Industrial Zone, Tantou Industrial City, Songgang Street, Baoan District, Shenzhen 518105, Guangdong, China
Type:Hex Shoulder Screw White Zinc Plated Iron
Materials:Steel
Surface treatment:White Zinc Plated
Head Type:Hex Head
Drive:External hex
Thread:Machine thread
Point:Chamfered lead-in
Forming:Multi-station heading
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:874
We make hex shoulder screws in white zinc plated carbon steel with a toleranced shoulder, a chamfered lead-in and a machine thread, quoting them from M1 to M14. Shoulder tolerance and length, chamfer, head and thread come from your drawing, and the first article is fitted into your bore.
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ISO 9001:2015 · Manufacturing since 1998 · 8,678+ customers · 89 countries and regions
Made to order – there is no stock catalogue. Each part is produced to your drawing, and production starts after drawing review and first-article approval.
A hex shoulder screw is a fastener with an external hex head, a toleranced plain shoulder and a machine thread, made here in white zinc plated carbon steel and quoted from M1 to M14 with Number 874. The shoulder runs in a bore as a bearing, the hex head clamps and gives a wrenching surface, and a chamfer at the end of the shoulder lets the part start into the bore.
Hex head. Six flats with a flat bearing face, so the screw can be driven with a wrench and clamped without a recess.
Shoulder. A plain turned or formed section, toleranced to the bore it runs in, that carries the radial load.
Chamfered end. A lead-in at the shoulder end that guides the part into the hole instead of catching on its edge.
White zinc plated carbon steel. A thin sacrificial deposit, bright and economical, gauged again after plating.
Most of a hex shoulder screw is dimensioned for the joint, but the chamfer at the end of the shoulder is dimensioned for the person assembling it. A shoulder that ends in a square edge will not enter a bore unless it is perfectly aligned, and a bore is almost never perfectly aligned when a part is going in by hand. A chamfer of the right angle and length finds the hole and pulls the screw into line as it goes.
The chamfer needs length as well as angle. Its axial length has to be longer than the clearance between the shoulder and the bore, or the shoulder touches the far edge before the chamfer has done its work. On a shoulder that runs with a few hundredths of clearance this is easily met; on a loose fit in a rough bore the chamfer has to be longer.
The chamfer also protects the plating. White zinc is thin, and a sharp shoulder edge loses its coating on the first assembly and starts to rust at the one place nobody inspects. A chamfer moves the contact onto a surface that can be worn without starting a corrosion site at an edge.
The seat under the head is the other end of the same question. The hex head has a flat bearing face, and the shoulder has to meet it at a clean corner so the head sits flat on the part. A radius left by the tool holds the head off the face and tips the shoulder in its bore, and a small relief under the head is what prevents it.
Why a hex head at all: on a shoulder screw the head often has to be tightened against a shoulder that must not rotate, from the side, with a wrench rather than from above with a bit. A hex also gives a larger bearing face than a cap head of the same across-flats, which helps when the part is a casting with a rough face.
The recorded range is M1 to M14, with the small and medium shoulder sizes covering appliance, furniture and small machine linkages. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission. For a hex shoulder screw the quotation carries the head across flats and height, shoulder diameter and tolerance, shoulder length, chamfer and thread.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Hex head, external | Across flats, height and face flatness |
| Shoulder | Toleranced plain section | Diameter, tolerance and length |
| Chamfer | Lead-in at the shoulder end | Chamfer angle and length |
| Thread | Machine thread | Pitch, length and gauging after plating |
| Plating | White zinc over carbon steel | Thickness and coverage on the chamfer |
| Material | Carbon steel | Grade and heat number on the certificate |
| Relief | Undercut under the head | Depth and corner form |
Chamfer angle and length are worth putting on the drawing as a pair. A 45-degree chamfer of a certain axial length gives a predictable lead-in; a 30-degree chamfer of the same axial length has a different entry diameter and behaves differently in a blind hole.
Shoulder tolerance and shoulder length remain the two functional dimensions. The chamfer helps the part go in; it does not make an out-of-tolerance shoulder fit, and it does not change how deep the shoulder sits.
Three features define the part: the chamfered shoulder, the hex head and the white zinc finish. The first gets the part into the hole, the second clamps and drives it, and the third is the only corrosion protection the steel has.
| Feature | What it gives | What it costs |
|---|---|---|
| Chamfered lead-in | Starts into a bore without catching | Removes bearing length at the end |
| Hex head | Wrench drive and a wide bearing face | Head stands above the surface |
| White zinc | Bright, sacrificial, economical | Thin coat; wears at edges |
| Toleranced shoulder | A bearing fit in a bore | Must be held through plating |
| Carbon steel body | Strength at low cost | Needs the coating for corrosion |
The lead-in is the feature customers notice after assembly rather than before. A batch of shoulder screws without a proper chamfer turns a bench job into a fitting job, because every part has to be lined up by eye before it will start.
The hex is the feature they notice when tightening. A wrench on six flats takes more torque than a recess in the same head, and it does not cam out, which is why these parts are common on joints that are tightened once and left.
The recorded finish is white zinc plating over carbon steel. On a hex shoulder screw that finish is doing all of the corrosion work: the deposit is sacrificial, a scratch leaves the surrounding zinc to protect the steel, and it is thin enough that the thread still gauges. On the shoulder it adds a few microns to the diameter, which is why the shoulder is gauged after plating.
| Option | How it protects | Effect on shoulder and chamfer | Typical use |
|---|---|---|---|
| White zinc plated | Sacrificial zinc, bright | Thin build; shoulder re-gauged | Furniture and general machinery |
| Zinc nickel | Alloy coating, higher salt resistance | Build allowed at the thread | Outdoor and automotive |
| Black oxide | Conversion film, oiled | No measurable build | Internal mechanisms |
| Dacromet | Inorganic zinc-aluminium layer | Thick; shoulder masked or ground | Wet assemblies |
| Stainless alternative | Passive film, no build | Shoulder and chamfer as made | Wet and food service |
Where the joint is outdoors or washed, white zinc is the wrong answer and the coated steel versions only postpone the problem. The stainless shoulder screw is the specification that removes the corrosion question from the shoulder entirely.
Where the part is in a dry interior, white zinc is the economical choice and the chamfer is the place to look after it. A chamfer that is plated over without a bare patch is what keeps the entry end from rusting first.
Three assemblies where a hex shoulder screw is the fixing:
| Where it sits | The screw forms the pivot of a furniture hinge or a bracket where the shoulder is the bearing and the head is tightened from the front with a spanner. |
| When it goes wrong | A square-ended shoulder will not start in a blind hole, and the fitter forces it and damages the bore. |
| Why it happens | The joint is assembled by hand, the bore is blind, and the shoulder is a running fit. |
| What we control | Chamfer angle and length checked; first article fitted in the bore. |
| Where it sits | The screw pivots a lever or a link where the hex head can be reached with a wrench and the shoulder locates the arm. |
| When it goes wrong | Shoulder play makes the linkage rattle, and a plated shoulder in a dry bore wears the zinc through. |
| Why it happens | The joint rotates, the head is accessible from the side, and the fit is set. |
| What we control | Shoulder tolerance held; first article moved through its travel. |
| Where it sits | The screw holds a panel at a fixed stand-off where the head has to clamp a painted or coated surface without crushing it. |
| When it goes wrong | A large hex head that is tightened without care marks the paint, and a short shoulder lets the panel move. |
| Why it happens | The joint sets a distance, the panel is coated, and the head is visible. |
| What we control | Face flatness and shoulder length checked; torque set with the customer. |
Four reasons that matter on a plated pivot, each tied to what the drawing has to prove:
|
Chamfer and shoulder agreed
The chamfer angle and length, shoulder tolerance, shoulder length and thread are agreed together, because on a hex shoulder screw the lead-in and the fit both have to work. Basis: Chamfer and shoulder agreed. |
Formed, threaded and plated in one route
The hex head and shoulder are formed, the chamfer is cut, the thread is rolled and the parts are plated and re-gauged within one route. Basis: One route from wire to plated part. |
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Shoulder gauged after plating
The shoulder is gauged after plating at several points, because white zinc adds to a diameter that is already a fit. Basis: Shoulder gauged after plating. |
Chamfer held per setup
The chamfer angle and length are set once and recorded, so a repeat order still starts into the same bore. Basis: Chamfer recorded from the first article. |
Shi Shi Tong forms hex shoulder screws on multi-station headers that upset the hex head, form the shoulder, cut the chamfer and roll the machine thread, then white zinc plates the parts and re-gauges the shoulder and thread. The first part of every run is measured on across-flats, shoulder diameter and length, chamfer and thread before the batch continues.
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The chamfer is cut by a tool that also has to leave the shoulder round. A worn tool leaves a chamfer that is uneven around the circumference, so the part starts into a bore on one side and rocks; the shoulder then measures inside tolerance and the fit is still wrong.
What decides whether hex shoulder screws pass is the shoulder, the chamfer, the head and the thread. The inspection agreement covers those, and the criteria come from the drawing.
Shoulder and chamfer on the projector |
Thread gauged after plating |
Hardness checked on the wire |
Coating proved by salt spray |
The shoulder is measured for diameter and roundness at several positions, the chamfer for angle and for how evenly it runs round the part, and the head for across-flats and height. The thread is gauged after plating, and the coating is checked for thickness and for bare patches at the chamfer.
The first article is fitted into the bore it serves. A shoulder screw that measures correctly and will not start is still a part that fails, and only the bore test shows it.
Every shipment of hex shoulder screws is traceable to the wire it was made from and to the plating batch. The grade and heat number are recorded on the material certificate supplied with the parts, and the inspection records follow the criteria agreed on the drawing.
ISO 9001:2015 |
RoHS test report |
Registered trademark |
Patent: security screw and driver |
With each batch we supply the material certificate, the inspection record for the criteria on the drawing and, where it is listed, the third-party report for the coating. The documents carry the drawing revision and the batch number, so a repeat order is made to the same shoulder tolerance and the same chamfer that were approved.
More than 8,678 customers in 89 countries and regions have ordered from Shi Shi Tong; 87% of orders come from repeat customers and 56% through referrals. Most projects follow the same route: drawing review, first-article approval, then batches checked against that sample. On a hex shoulder screw the first article is fitted into the customer bore, because the fit is the function. Buyers visit during the process to review samples and to see how the parts are formed.
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8,678+
customers served
|
87%
of orders from repeat customers
|
56%
of orders through referrals
|
89
countries and regions shipped to
|
Buyers and quality engineers visit for sample review, process discussion and supplier audits; the visit is arranged around production so the headers and the plating line can be seen on the day the parts run.
Customer group visit – sample review |
Customer group visit – process discussion |
Customer group visit – factory tour |
Customer visit – project kick-off |
Danish customer – drawing review |
Industry exhibition – meeting customers |
So the part starts into the bore instead of catching on its edge. On a blind hole or a hand assembly the chamfer is what makes the part fit first time.
Its axial length has to be longer than the clearance between the shoulder and the bore, so the chamfer can pull the part into line.
It takes the contact when the part enters. A chamfer spreads that contact, and a bare patch there is where corrosion starts.
Shoulder length for the bearing, and thread length from the shoulder end. The chamfer is included in the shoulder length as drawn.
White zinc adds a few microns, so the shoulder is gauged after plating rather than before.
Head across flats and height, shoulder diameter and tolerance, shoulder length, chamfer angle and length, thread and the coating.
How a hex shoulder screw project runs from drawing to repeat delivery:
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1
Send the drawing and the bore it fits
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→ |
2
Chamfer, shoulder and thread agreed
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→ |
3
First article fitted into your bore
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→ |
4
Batch production and repeat orders
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Each step is confirmed with you before the next one starts; the drawing revision from the first article is what repeat orders are checked against.
For a quotation, send the drawing with the head across flats and height, shoulder diameter and tolerance, shoulder length, chamfer, thread and the coating.
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Head A/F
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Head height
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Shoulder diameter
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Shoulder length
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Chamfer
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Thread
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Sending a drawing? The form below does not take attachments. Email the PDF, DXF or STEP file to sst@szsst88.com with the part name and quantity in the subject line – the drawing is reviewed and a quotation follows.
+86 13143444311
sst@szsst88.com
