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+86 13143444311
Email：sst@szsst88.com
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Address：Building 9, First Industrial Zone, Tantou Industrial City, Songgang Street, Baoan District, Shenzhen 518105, Guangdong, China
Type:Miniature Shoulder Screws Self Tapping
Materials:Stainless Steel
Surface treatment:Plain
Head Type:Low Head
Drive:Phillips (cross)
Thread:Self-tapping, thread forming
Point:Sharp, tapered
Forming:Single Die Heading
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:797
We make miniature shoulder screws in passivated A2 stainless that combine a low head, a plain shoulder and a self-tapping thread, quoting them from M1 to M14. Head height, recess depth, shoulder length, thread and pilot hole come from your drawing, and the first article is driven into your boss.
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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.
Miniature shoulder screws are small stainless fasteners that combine a low head, a plain shoulder and a self-tapping thread, quoted here from M1 to M14 with Number 797. The shoulder passes through a plain hole in one part, the thread cuts its own thread in the other, and the low head lets a cover sit over the fixing without a counterbore.
Low head. A shallow head that stands only a fraction above the surface, with a Phillips recess cut into it.
Shoulder. A plain cylindrical section that runs in a plain hole and locates or pivots the joint.
Self-tapping thread. A coarse, sharp-crested thread that forms its own thread in plastic or thin sheet as it is driven.
Passivated stainless. A2 grade, uncoated, so the head, the shoulder and the thread are as made.
Miniature shoulder screws are specified where a plastic housing, a bracket and a pivot meet and there is no room for an insert, a washer or a counterbore. One part carries the locating shoulder, the thread-forming end and a head low enough to be covered.
These miniature shoulder screws are asked to do three things at once, and each one wants space the others do not have. The head has to be thin so a cover sits over it; the recess has to be cut into that thin head, so it is shallow; the shoulder has to be plain and close-fitting, so no thread can pass through it; and the thread has to form its own thread in a plastic boss, which needs a wall thick enough to take the displaced material.
The low head sets the torque limit first. A shallow Phillips recess engages a short length of bit, and the head above the recess is thin, so the screw fails at the drive or at the head before the thread does. On these parts the driving torque is set by the head, not by the joint, and the assembly instruction has to say so.
The shoulder then has to be long enough to do its locating job and short enough to leave thread in the boss. If the shoulder takes most of the length, the thread engages only a thread or two and the joint pulls out; if the thread runs up to the head, the shoulder does nothing and the part becomes an ordinary self-tapping screw with a thin head.
The self-tapping thread is the third constraint. In plastic it displaces material as it forms, so the boss wall has to be at least the thread height plus a wall, and the pilot hole has to be sized so the thread cuts without splitting. Brass or steel screws can be given more torque to seat; a stainless miniature screw will twist off at the shallow head first.
What the combination gives is an assembly that needs no insert, no nut and no counterbore. A bracket is placed over a plastic boss, the screw passes through the bracket on its shoulder and cuts into the boss, and the low head leaves a flat surface above it. That is a cheap joint with three functions in one part, and it only works if each function is dimensioned.
The recorded range is M1 to M14, with M1.4 to M3 covering the miniature work. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission. For miniature shoulder screws the quotation carries the head height, recess depth, shoulder diameter and length, thread size, thread length and the pilot hole in the boss.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Low profile, shallow | Head diameter and head height |
| Recess | Phillips cross | Recess size and depth in the low head |
| Shoulder | Plain locating section | Diameter, tolerance and length |
| Thread | Self-tapping, thread forming | Thread form, length and crest condition |
| Point | Sharp, tapered | Point length and concentricity |
| Material | A2 stainless | Grade and heat number on the certificate |
| Finish | Passivated | Surface condition and film |
Head height should be given with a tolerance, because on miniature shoulder screws the head is the clearance feature. A head a few hundredths high is a cover that does not sit flat, and there is no washer or counterbore to hide it.
The pilot hole in the plastic belongs on the assembly drawing while the thread form belongs on the screw drawing. The two decide the joint together, and neither is complete on its own.
Three features define the part: the low head, the shoulder and the self-tapping thread. The first keeps the surface clear, the second locates the joint, and the third removes the need for a tapped hole or an insert.
| Feature | What it gives | What it costs |
|---|---|---|
| Low head | A cover can sit over it | Shallow recess, low torque limit |
| Shoulder | Locates and can pivot | Takes length away from the thread |
| Self-tapping thread | No insert or tapped hole | Boss must be thick enough |
| Passivated stainless | No plating in recess or thread | Softer than steel; galls dry |
| Sharp point | Starts in a drilled pilot | Less thread in a thin boss |
The joint without an insert is the economic argument. A moulded boss plus a self-tapping screw costs less than a threaded insert plus a machine screw, and for a joint that is assembled once and rarely opened, the difference in holding power is not what decides the specification.
The cost is that every function is at its limit. The head has no height to spare, the recess has no depth to spare, the shoulder has no length to spare and the boss has no wall to spare; a customer who needs more of any one of them needs a different part.
The recorded finish is passivation with no coating on A2 stainless. For miniature shoulder screws that is the right finish because both the recess and the shoulder are at their limit: a coating on a shallow recess narrows the driver fit, and a coating on the shoulder changes the locating diameter by an amount that matters at these sizes.
| Option | How it protects | Effect on head and shoulder | Typical use |
|---|---|---|---|
| A2 stainless, passivated | Passive chromium oxide film | Head and shoulder as made | Plastic housings and brackets |
| A4 stainless, passivated | Passive film with molybdenum | Head and shoulder as made | Medical and marine devices |
| Steel, nickel plated | Hard barrier deposit | Recess narrowed; re-checked | Indoor consumer parts |
| Steel, black oxide | Conversion film, oiled | No measurable build | Internal mechanisms |
| Brass, plain | No coating needed | Softer head; recess wears sooner | Decorative and electrical |
Where the joint is opened more than a few times, stainless is the better choice than a plated steel, because the shallow recess keeps its shape and the shoulder keeps its diameter through repeated assembly.
Where the boss is very soft, a thread-forming screw can be replaced by a thread-cutting one with a slot in the point, which leaves a cleaner thread but also leaves a chip. That is a decision for the joint design, not for the finish.
Three assemblies where miniature shoulder screws are the fixing:
| Where it sits | The screw holds a bracket over a moulded boss where the head must sit below the cover line and the shoulder locates the bracket. |
| When it goes wrong | A boss that is too thin splits, and a pilot hole that is too large never holds. |
| Why it happens | The joint is plastic, it is small, and it is assembled once. |
| What we control | Pilot hole agreed with the customer; first article driven into a sample boss. |
| Where it sits | The screw forms the pivot of a small flap where the shoulder runs in the flap and the thread holds in the body. |
| When it goes wrong | The shoulder binds in the flap, and a shallow recess rounds at the first service. |
| Why it happens | The joint moves, the parts are small, and the pivot is serviced. |
| What we control | Shoulder tolerance and head height checked; first article swung through its travel. |
| Where it sits | The screw locates a plate on a plastic or thin-sheet substrate where an insert would be too large for the space. |
| When it goes wrong | An over-long shoulder leaves the plate proud, and a short one lets it move. |
| Why it happens | The joint sets a position, the space is tight, and the plate is thin. |
| What we control | Shoulder length matched to the plate stack; head clearance checked. |
Four reasons that matter on a three-function part, each tied to what the drawing has to prove:
|
Head, shoulder and thread agreed
Head height, recess depth, shoulder length and thread length are agreed together, because on miniature shoulder screws each one takes space from the others. Basis: Head, shoulder and thread agreed. |
Formed, threaded and finished in one route
The low head and recess are formed, the shoulder is sized, the self-tapping thread is rolled and the parts are passivated in one route. Basis: One route from wire to passivated screw. |
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Driven into the customer boss
The first article is driven into a sample boss at the assembly torque, because the thread is made in that material and nowhere else. Basis: First article driven in customer material. |
Head height recorded
Head height and shoulder length are recorded from the first article, so repeat orders keep the cover clearance the customer approved. Basis: Head and shoulder recorded. |
Shi Shi Tong forms miniature shoulder screws on single-die headers that form the low head and cut the Phillips recess in one stroke, sizes the shoulder, rolls the self-tapping thread and grinds the point before passivating the parts. The first part of every run is measured on head height, recess depth, shoulder diameter and length, and driven into a sample boss before the batch continues.
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A low head with a shoulder behind it is harder to form than either alone. The punch has to stop the metal at a head height it would rather overshoot, and the shoulder has to come out of the same strike with enough length to locate; a worn punch leaves a head a little high, and the cover no longer closes over it.
What decides whether miniature shoulder screws pass is the head height, the recess, the shoulder diameter and length, the thread and the point. The inspection agreement covers those, and the criteria come from the drawing.
Head and shoulder on the projector |
Thread and point checked |
Hardness checked on the wire |
Salt-spray testing of the grade |
The head is measured for height on the projector rather than with a caliper, because the top is domed and a caliper reads the high point. The recess is checked for depth, the shoulder for diameter and length, and the thread and point for form and concentricity.
The first article is driven into the customer boss and checked for split, for strip torque and for how much the head stands above the cover line. That is the assembly check these parts are bought for, and none of it can be measured on the screw alone.
Every shipment of miniature shoulder screws is traceable to the wire it was made from and to the passivation 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 grade. The documents carry the drawing revision and the batch number, so a repeat order is made to the same head height and shoulder length 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 miniature shoulder screws the first article is driven into the customer boss, because the thread and the fit are made in that boss. Buyers visit during the process to review samples and to see how the parts are formed.
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8,678+
customers served
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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 point grinding station 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 a cover or a flap can sit over the fixing without a counterbore. The low head is the clearance feature, and its height is toleranced.
The recess is shallow because the head is thin, so the bit engages a short length. Use the right bit and set the torque to the head.
Yes. The screw forms its own thread, but the pilot hole sets how much material it displaces and whether the boss splits.
It runs in a plain hole and locates or pivots the joint. Thread must not pass through it.
A few. Each drive cuts or re-forms the plastic thread, and the hold falls with every repeat.
Head diameter and toleranced height, recess size and depth, shoulder diameter and length, thread size and length, the point and the grade.
How a miniature shoulder screw project runs from drawing to repeat delivery:
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1
Send the drawing and a sample boss
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→ |
2
Head, shoulder and thread agreed
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→ |
3
First article driven into your boss
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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 diameter and height, recess size and depth, shoulder diameter and length, thread size and length, the point and the pilot hole.
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Head height
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Recess depth
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Shoulder diameter
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Shoulder length
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Thread
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Pilot hole
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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
