Stainless Steel Security Screws

We make stainless steel security screws with a five-point tamper drive, a centre pin and a button head, quoting them from M1 to M14 in passivated stainless. Drive size, head height, thread form and grade come from your drawing, and the first article is turned with the bit your site will use.

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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.

What Stainless Steel Security Screws Are

Stainless steel security screws are screws with a drive that an ordinary tool will not turn, in a body that survives weather and washing. The recorded item on this page is stainless with a plain finish, a button head and a five-point tamper drive, quoted from M1 to M14 with Number 255.

Five-point tamper drive. Five curved lobes with a small pin standing in the centre. A standard star or hex bit has nothing to seat on: the pin sits where the bit wants to go, and the lobes are the wrong count. Only the matching hollow bit turns it.

Button head. A low dome on a short cylindrical side, with a small flat bearing face. It reads as a smooth fastener rather than a machined one, which is why it appears on visible panels and public fittings.

Machine thread. A thread made to engage a tapped hole or a nut, with a blunt chamfered end. It does not cut its own way in, so the joint can be opened without damaging the part.

Stainless, plain. The alloy is the protection: a passive chromium oxide film that rebuilds itself after a scratch. There is no coating to chip at the drive, which matters because a security drive is small and a chipped coating there is a visible defect.

What security means here. A deterrent, not a lock. The bit exists and can be bought; what the drive does is make casual removal inconvenient enough that the fixing is left alone.

The Drive and What It Takes to Turn

On a stainless steel security screw the drive is a recess formed by a punch: five lobes, evenly spaced, with a pin in the middle. The pin is formed in the same stroke and is the feature that does the work, because it occupies the centre of the recess where any ordinary bit would try to seat. The lobes then have to be cut deep enough that the matching hollow bit can transmit torque without rocking.

That geometry sets the tolerance. On a five-lobe drive the bit contacts five flanks, and the pin sits in a hole that is a fraction of a millimetre across. A punch that has worn a few hundredths leaves a recess that takes the bit but lets it rock, and a bit that rocks on five lobes rounds them faster than on any cross recess, because each lobe is smaller.

The button head limits how deep the recess can go. A button head is a low dome with a short side, so the material above the bearing face is thin; the recess therefore has to be formed within that height, and on the smallest sizes the pin is the feature that sets the minimum head height. That is why a security screw is not simply a pan head with a different punch.

The thread is a machine thread with a blunt chamfered end. In this family the thread form follows the drawing: some parts are made with a plain machine thread for a tapped hole, and some with a trilobular thread that forms its own thread in a drilled or cored hole. The two are not interchangeable in the same hole, so the drawing states which.

Stainless is headed, rolled and passivated. Passivation is what removes free iron left by the forming tools and lets the oxide film rebuild; without it a stainless screw can show rust spots on a head that never saw service, and on a visible security fixing that reads as a material failure.

Sizes, Drive and Length

The family is quoted from M1 to M14, with M1, M2, M3, M4, M5, M6, M7, M8, M9, M10 and M14 in the recorded range. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission; on a stainless steel security screw the smallest size in the family is the one that decides how small the drive can be made.

Drive size and screw size are chosen together. A five-point drive on a very small screw has lobes that are hard to form and easy to damage; on a large screw the same drive would limit the torque below what the thread can take. The pairing is settled on the drawing, and the first article is the point at which the bit is confirmed to fit.

Length is measured from under the head, because that face bears on the part. On a button head the bearing face is small, so the joint relies on the hole being close to the head diameter; a length that runs long into a blind hole bottoms the screw before the face touches, and the head then stands proud with nothing to show why.

What a Tamper Drive Buys and Costs

Three features define a stainless steel security screw: the unusual drive, the button head and the alloy. The drive is a handling decision as much as a security one, and it is worth saying so plainly.

The honest limit of any security drive is that the tool is for sale. What the five-point pattern does is stop the person with a screwdriver in a pocket — the passer-by, the tenant, the customer in a fitting room. It does not stop someone who has decided to take the fixture apart, and it is a mistake to present it as if it did.

The cost lands on service. Every technician who opens that panel needs the hollow bit, and a bit that has worn or been lost turns a five-minute job into a damaged head. The practical answer is to supply bits with the first order and to standardise the drive across a product line, so one bit covers everything on site.

Stainless and the Small Drive

Stainless steel security screws are finished plain and passivated. Nothing is added to the drive, which is the point: a security recess has lobes measured in tenths of a millimetre, and a coating that builds a few microns there narrows the lobes and stops the bit seating. A plated security screw has to be checked with the bit after plating, every time.

Material and Finish Options for Security Screws

Stainless has two behaviours worth knowing at this size. The first is galling: stainless against stainless can seize, and a seized security screw is worse than an ordinary one because the drive has less material to work with. A lubricant, or a different grade for the mating nut, is the usual answer.

The second is chloride. A 304 screw on a coastal installation will pit at the drive, where water sits and air is excluded, and the pit eats the lobe that carries the torque. Where that service is expected, the grade is the answer rather than the finish, and the drawing should say which grade rather than leaving it open.

Where These Screws Are Used

Three assemblies where a stainless steel security screw is chosen to keep a fixing in place:

Why Shi Shi Tong for Stainless Steel Security Screws

Four reasons that matter on a tamper drive, each tied to what the drawing has to prove:

How These Screws Are Manufactured

Shi Shi Tong heads these stainless steel security screws from stainless wire on single-die headers that form the button head and the five-lobe recess with its centre pin in one stroke, rolls the machine thread to a blunt chamfered end and passivates the parts before packing. The first part of every run is measured on the head, turned with the production bit and entered into a thread gauge before the batch continues.

The drive punch is the tool that limits the life of the die. The pin wears first, because it is the smallest feature and it takes the load when a bit is not quite seated; a worn pin leaves a recess that looks right and lets the bit drop too deep, so the lobes carry load on their tips instead of their flanks. The drive is checked with the bit on the first article and sampled through the run.

Inspection: Drive, Head and Thread

What decides whether stainless steel security screws pass is the drive, the head, the thread and the alloy. The inspection agreement covers those, and the criteria come from the drawing.

Drive and pin on the projector	Thread gauged per batch
Hardness checked on the formed head	Salt-spray testing of the stainless grade

The drive is checked on the projector for lobe depth, lobe width and pin diameter, and then turned with the matching bit. The two checks answer different questions: dimensions say whether the recess is in tolerance, and the bit says whether it will transmit torque without rocking.

The head of a stainless steel security screw is checked for diameter, height and flatness of the bearing face. On a button head the bearing face is small, so a face that is not flat bears on a ring and the joint loosens; the check is made on the section of the first article as well as on the face.

The thread is gauged per batch and the alloy confirmed on the certificate. Where the drawing calls for a trilobular thread, the thread is checked against a sample of the cored hole as well as with a gauge, because the forming action is what the customer is buying.

Certificates and Material Documentation

Every shipment of stainless steel 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 or the passivation. The documents carry the drawing revision and the batch number, so the paperwork can be matched to the parts.

Customers and Projects

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 security drive the first article is also the point at which the bit is agreed, so the customer confirms the tool at the same time as the screw. Buyers visit during the process to review samples and to see how the heads and drives are formed.

Buyers and quality engineers visit for sample review, process discussion and supplier audits; the visit is arranged around production so the headers, the drive punches 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

Related Products and Guides

Technical Guides

Long Thin Screws: Drawing and Manufacturing Requirements What to put on the drawing for long, thin parts: datum, shank, thread position and handling. Read the guide

How Long Does It Take to Customize Extra-Long Screws? Where the time goes in a custom long-screw order, from drawing review to first article. Read the guide

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Custom Extra-Long Machine Screws Family page: mixed heads, drives and finishes up to 2,000 mm. Custom Extra-Long Machine Screws	Extra-Long Low-Profile Phillips Screws Low heads with a PH recess for recessed covers and black chassis panels. Extra-Long Low-Profile Phillips Screws	Extra-Long Hex-Head Dacromet Screws Long hex-head screws with a Dacromet coating for wet or outdoor assemblies. Extra-Long Hex-Head Dacromet Screws

Stainless Steel Security Screws FAQ

Order Stainless Steel Security Screws

How a stainless steel security screw project runs from drawing to repeat delivery:

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.