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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:Long Stainless Steel Screws Anti Theft Security
Materials:Stainless Steel
Surface treatment:Plain
Head Type:Flat Countersunk Head
Drive:Torx with centre pin
Thread:Machine thread, half thread
Point:Blunt
Forming:Single Die Heading
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:574
We make security screws in passivated A2 stainless with a countersunk head, a pin-in-Torx recess and a half thread, in long lengths quoted from M1 to M14. Recess size and pin, cone angle, lengths and thread come from your drawing, and the first article is driven with your hollow bit.
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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.
These are security screws: long stainless screws with a countersunk head, a half thread and a Torx recess with a pin in the centre. The pin stands in the middle of the star so an ordinary Torx bit cannot enter, and only a bit with a matching hole will turn the screw. They are quoted from M1 to M14 with Number 574.
Pin-in-Torx recess. A six-lobe star with a short pin standing in its centre, so a solid bit is blocked and a hollow bit fits.
Countersunk head. A flat head that seats flush, leaving no edge to grip with pliers.
Half thread. The plain shank runs through the joint and the thread engages only at the far end.
Passivated stainless. A2 grade, uncoated, so the recess and the seat are as made.
Screws like these are used where a panel has to stay closed to the public but open to a technician: equipment housings, signage, access covers. The pin and the flush head do the deterring, and the long half-threaded shank does the joining.
A security screw is a deterrent, and it works by removing the tools that would otherwise turn it. The pin in the recess does that for the drive: a standard Torx bit is solid, so it bottoms on the pin and never reaches the lobes; a hollow bit drops over the pin and engages. The screw is not unremovable, but it cannot be turned with what an ordinary toolbox contains.
The countersunk head does the same for the head. A pan or button head can be gripped from the outside with pliers or a small wrench when the recess fails, which is the usual way a security fixing is defeated in practice. A flat head has no outside to grip: it sits in its cone with the top almost flush, so once the recess is inaccessible there is nothing left to hold.
The two features together are what make this part useful. A pin-in-Torx screw with a tall head is a screw that can still be taken out with pliers; a flat head with a normal recess is a screw that can be taken out with any tool. The combination is the version that actually resists casual access.
The pin also changes how the screw is made and driven. It stands in the centre of a small star, so on the smallest sizes the recess has to be cut with the pin formed in the same operation, and the hollow bit has to match the pin diameter as well as the star size. A bit that fits the star but not the pin will not seat, and a bit whose hole is too large will rock.
The long shank and half thread belong to the joint rather than to the security. These parts are used where the fixing passes through a panel or a spacer and threads into a part behind it, and the plain section keeps the passage smooth while the security feature keeps the joint closed.
The recorded range is M1 to M14, with long lengths made to the drawing. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission. For security screws the quotation carries head diameter and cone angle, overall length, thread length, the recess size with its pin, and the grade.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Countersunk, 90-degree cone | Head diameter and cone angle |
| Recess | Torx with centre pin | Recess size, pin diameter and depth |
| Length | Overall, head included | Length tolerance and end chamfer |
| Thread | Half thread | Pitch, length and gauging |
| Material | A2 stainless | Grade and heat number on the certificate |
| Finish | Passivated | Surface condition and film |
| Bit | Hollow Torx bit | Pin size confirmed with the recess |
The recess description belongs on the drawing as a size plus a pin dimension, not just as a star size. Two parts can both be called a Torx and differ in the pin, and the bit that fits one will not fit the other.
Overall length is quoted including the head, because a countersunk head sits inside the part. A security screw quoted under the head will be a head height short in the joint, and on a long part that error is not obvious until assembly.
Three features define the part: the pin in the recess, the countersunk head and the long shank. The first blocks a normal bit, the second removes the pliers route, and the third gives the reach.
| Feature | What it gives | What it costs |
|---|---|---|
| Torx pin | Blocks a solid bit | Needs the matching hollow bit |
| Countersunk head | No edge to grip with pliers | Seat angle and depth must match |
| Long shank | Reaches through the joint | Twists under driving torque |
| Half thread | Front part stays unthreaded | Both lengths must be specified |
| Passivated A2 | Recess and seat as made | Galls dry against stainless |
The blocked drive is the whole point, and it is worth being clear about what it does. It stops an unauthorised person with a normal set of tools; it does not stop someone who has decided to buy the hollow bit. A security screw is a delay, not a lock.
The flush head is the part that is often underestimated. Most attempts to defeat a security fixing end with pliers on the head, and a flat head gives them nothing to hold. That is why these screws are countersunk rather than pan headed.
The recorded finish is passivation with no coating on A2 stainless. On a security screw that matters more than usual: the recess is small and carries a pin, and a coating would narrow the star and the pin clearance at the same time, so the hollow bit that fits an uncoated part may not fit a plated one.
| Option | How it protects | Effect on recess and head | Typical use |
|---|---|---|---|
| A2 stainless, passivated | Passive chromium oxide film | Recess and pin as made | Outdoor and general security |
| A4 stainless, passivated | Passive film with molybdenum | Recess and pin as made | Marine and chemical |
| Steel, zinc plated | Sacrificial zinc | Recess narrowed; re-checked | Indoor general work |
| Steel, black oxide | Conversion film, oiled | No measurable build | Internal mechanisms |
| Steel, black zinc | Sacrificial zinc, dark | Recess narrowed; re-checked | Dark housings |
Where the joint is wet, A4 is the grade, and the reason is the recess: a security screw that rusts in its star cannot be removed at all, because the bit no longer seats and there is no head to grip.
Where a coated steel version is used, the recess is gauged after plating. The pin clearance is the number that suffers first, and a hollow bit that will not drop over the pin turns a security screw into a permanent one.
Three assemblies where security screws are the fixing:
| Where it sits | The screw holds a cover on equipment in a public place, where the fixing has to resist casual removal rather than a determined attack. |
| When it goes wrong | A standard recess is undone with any driver, and the cover is opened. |
| Why it happens | The panel is public, the fixing is visible, and the contents matter. |
| What we control | Recess and pin checked with the hollow bit; first article driven. |
| Where it sits | The screw fixes a sign or a fitting where the head must be flush and removal by an unauthorised person is the concern. |
| When it goes wrong | A tall head can be gripped with pliers, and the fixing is defeated. |
| Why it happens | The joint is exposed, the head is flush, and the risk is opportunistic. |
| What we control | Cone and recess checked; first article seated in the seat. |
| Where it sits | The screw closes a panel that only a technician should open, where the same brand of security bit is issued to the trade. |
| When it goes wrong | A recess that rusts or fills with paint stops the technician as well as the public. |
| Why it happens | The joint is serviced rarely, it is outdoors, and access is controlled. |
| What we control | Recess gauged and protected from paint; first article operated. |
Four reasons that matter on a part with a pin in the recess, each tied to what the drawing has to prove:
|
Recess and pin agreed
The star size and the pin diameter are confirmed together, because on security screws the bit has to match both to engage. Basis: Recess and pin agreed. |
Formed with the pin in place
The head and the star are formed with the pin in one route, then the thread is rolled and the parts passivated. Basis: Pin formed with the recess. |
|
Driven with the hollow bit
The first article is driven with the hollow bit the customer uses, because a recess that measures correctly can still reject the bit. Basis: Driven with the hollow bit. |
Bit specification recorded
The recess size and pin are recorded with the batch, so a repeat order cannot arrive with a recess that needs a different bit. Basis: Bit specification recorded. |
Shi Shi Tong forms these security screws on single-die headers that form the countersunk head and cut the star recess with its centre pin, then rolls the half thread and passivates the parts. The first part of every run is measured on head diameter, cone angle, recess and pin, overall length and thread before the batch continues.
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The pin is the hard part of a security screw. It is a short post standing in the middle of a small star, and it has to be formed without closing the lobes around it or leaving a burr that stops the bit dropping in; a pin that is slightly off-centre makes the recess look right and reject the bit on one side.
What decides whether security screws pass is the recess, the pin, the cone and the thread. The inspection agreement covers those, and the criteria come from the drawing.
Recess and pin on the projector |
Thread gauged per batch |
Hardness checked on the wire |
Salt-spray testing of the grade |
The star is checked for size and depth, the pin for diameter, height and concentricity, and the cone for angle and contact. The thread is gauged, and the recess is checked again on the finished part for burrs that would stop the bit.
The first article is driven and released with the hollow bit the customer will use. A security screw that measures correctly and rejects the bit is a part with no way to remove it, and only that test shows it.
Every shipment of security 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 keeps the same recess and pin.
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 security screws the first article is driven with the hollow bit the customer issues to their technicians, because the bit is part of the system. Buyers visit during the process to review samples.
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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 passivation 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 |
It blocks a solid Torx bit; only a hollow bit with a matching hole will drop over it and engage the lobes.
No. The hollow bit is available. It is a deterrent that stops casual access with ordinary tools, not a lock.
There is no edge to grip with pliers, so a failed recess cannot be bypassed from outside.
It can narrow the star and the pin clearance, so on coated parts the recess is gauged after plating.
Usually a burr in the recess or a pin that is off-centre; both are checked on the first article with the customer bit.
Head diameter and cone angle, overall length, recess size and pin, thread, the grade and the finish.
How a security screw project runs from drawing to repeat delivery:
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1
Send the drawing and the bit you issue
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→ |
2
Recess, pin, length and thread agreed
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→ |
3
First article driven with your hollow bit
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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 cone angle, overall length, thread length, recess size and pin, the grade and the finish.
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Head diameter
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Cone angle
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Overall length
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Recess size
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Pin
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Grade
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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
