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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:torx machine screws
Materials:Stainless Steel
Surface treatment:Plain
Head Type:Flat Head (Csk)
Drive:Six-lobe star recess (Torx)
Thread:Machine thread
Point:Plain, chamfered
Forming:Single Die Heading
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10
Number:886
We make Torx machine screws in plain A2 stainless with a countersunk head and a six-lobe recess, quoting them from M1 to M10. Cone angle, head thickness, Torx size and thread come from your drawing, and the first article is driven with your own key.
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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.
Torx machine screws are screws with a six-lobe star recess and a machine thread, driven with a Torx key and closed into a tapped hole, a nut or an insert. These are countersunk, plain A2 stainless, quoted from M1 to M10 with Number 886, in the small sizes where a cross recess is easy to damage.
Countersunk head. A cone that seats in a countersink so the head finishes flush with the surface.
Six-lobe recess. A star socket driven from the centre of its walls, which does not lift the key as torque rises.
Machine thread. A uniform thread for a tapped hole or a nut, so the joint can be reopened without damaging the panel.
Plain stainless. A2 grade, passivated and uncoated, so the cone and the recess are as formed.
Torx machine screws are used where a small screw has to be driven and reopened without damaging the drive: instruments, camera and optical hardware, electronic housings and small machinery. The star recess is what makes that possible at M1.4, where a cross recess would be rounded after a few cycles.
A countersunk head is mostly cone. The flat face that carries the recess is a small circle at the top, and its width is set by the head diameter and the cone angle. Every feature of the drive has to fit in that circle, and at small sizes the circle is only a few millimetres across.
The star recess works inside it better than a cross, because it is driven from the walls of the lobes rather than from the edges of arms. Each lobe presents an inclined face to the key, and the key pushes on that face at an angle that holds it in rather than lifting it out. At M2 with a key of a millimetre or two across, that difference is what stops the tool climbing out of a head that cannot be gripped anywhere else.
What the form does not solve is depth. The recess has to be cut deep enough for the key to engage, and shallow enough to leave metal between its floor and the cone below. On a countersunk head those two limits are close together, and a recess cut a few hundredths too deep gives a head that measures correctly and deforms under the first real torque.
There is also the transition under the head. A plain countersunk machine screw has a small formed radius where the cone meets the shank, and in a countersink that has been cut square that radius can touch the bottom of the seat before the cone face does, leaving the head a fraction proud. This is the reason an undercut version exists for joints where the seat has to be bottomed, and it is worth knowing which one the drawing calls for.
Stainless adds wear. The key is harder than the screw, so a stainless star recess that is driven hard, or driven with a key that is a size small, rounds at the lobe crests over repeated cycles. The recess survives far better than a cross, but it is not indestructible, and a worn key damages the head long before the thread gives up.
The recorded range is M1 to M10, with lengths made to the drawing. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission. For Torx machine screws the quotation carries head diameter, cone angle and thickness, the T-size and depth of the recess, thread and overall length.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Countersunk, 90-degree cone | Diameter, angle, thickness and rim |
| Recess | Six-lobe star, T-size per diameter | Lobe form, depth and floor thickness |
| Thread | Machine thread | Pitch, length and start position |
| Length | Overall, head included | Length tolerance and thread start |
| Material | A2 stainless | Grade and heat number on the certificate |
| Finish | Passivated, plain | Surface condition and recess edges |
Torx size follows the diameter and should be written as a T number on the drawing. A T8 key in a recess formed for T6 will turn until the lobes are destroyed, and because the key looks close to the right size, the damage is usually blamed on the operator rather than on the tool.
Head thickness is the number that limits the recess. On a small countersunk head there is very little material above the cone, and the drawing should state both the head thickness and the recess depth so that the remaining floor is a known quantity.
Four features define Torx machine screws at small sizes, and each one has a consequence:
| Feature | What it gives | What it costs |
|---|---|---|
| Six-lobe recess | Torque without cam-out | Only a Torx key fits; a worn key reams it |
| Countersunk cone | Flush, self-centring seat | Thin head; limited recess depth |
| Machine thread | Joint can be reopened | Needs a tapped hole or a nut |
| Small sizes | Fits instruments and electronics | Little material above the cone |
| Plain stainless | Recess as formed; no coating | Softer than the key; galls in aluminium |
The recess is the reason to choose this screw over a cross recess at the same size. In a service cover that is opened a few times a year, a cross recess eventually rounds; a star recess, driven with the correct key, keeps its form for the life of the assembly.
The cost on Torx machine screws is tool discipline. A star bit that is one size small seats part way, feels engaged and then reams the lobes at the first hard turn. There is no partial engagement that works, which is why the T-size belongs on the drawing and on the assembly instruction.
The recorded finish is passivation on A2 stainless with no coating. On a small countersunk Torx screw that matters at the recess edges, which are the thinnest features on the part: a coating would round them, and a rounded edge is what lets a key sit slightly high and load the lobes at the wrong angle.
| Option | How it protects | Effect on recess and cone | Typical use |
|---|---|---|---|
| A2 stainless, passivated | Passive chromium oxide film | Recess and cone as formed | Instruments and housings |
| A4 stainless, passivated | Passive film with molybdenum | Recess and cone as formed | Medical and marine |
| Stainless, electropolished | Thicker passive film, bright | Slight edge rounding; recess checked | Visible hardware |
| Steel, black oxide | Conversion film, oiled | No measurable build | Optical assemblies |
| Steel, zinc plated | Sacrificial zinc | Build in lobes; re-checked | General indoor work |
Where the screw is visible, electropolishing on Torx machine screws brightens the cone and removes the burr at the recess edge that a key would catch. It also rounds the edges slightly, which is why the recess is checked after the process rather than before.
Where a coated steel screw is used, the recess is gauged after plating. A star recess takes build worse than a cross, because the lobes are narrow and the key has nowhere to clear.
Three assemblies where the star recess earns its place at small size:
| Where it sits | The screw closes a lens mount or a housing where the head must sit flush and the joint is reopened for adjustment. |
| When it goes wrong | The recess rounds and the adjustment cannot be repeated. |
| Why it happens | The screw is small, the head is flush, and the joint is serviced often. |
| What we control | T-size and recess depth checked; first article driven with the production key. |
| Where it sits | The screw fixes a cover or a board bracket where the head sits in a countersink and the thread is in a standoff. |
| When it goes wrong | The key slips and marks the housing around the recess. |
| Why it happens | The space is tight, the drive is internal, and the head is countersunk. |
| What we control | Recess centred and gauged; first article assembled in the housing. |
| Where it sits | The screw holds an adjustment or a lever where the joint is set, checked and reset before final tightening. |
| When it goes wrong | A worn key damages the lobes before the thread is fully loaded. |
| Why it happens | The joint is adjusted repeatedly and the drive is a Torx key. |
| What we control | Recess and thread checked; first article adjusted and locked. |
Four reasons that matter on a small countersunk star screw, each tied to something the drawing has to prove:
|
T-size and cone agreed
Torx size, recess depth, cone angle and head thickness are agreed as a set, because on a small countersunk head each one limits the others. Basis: Torx size and cone agreed. |
Formed, socketed and passivated in one route
The cone and star recess are formed in one stroke, the thread rolled, and the parts passivated as a batch. Basis: One route from wire to passivated screw. |
|
Recess proved with the production key
The recess is checked with the key the line uses, because a recess that takes a new key and fails a worn one is not a pass. Basis: Recess proved with the key. |
First article seated in your countersink
The first article is seated in the customer countersink, because flushness and the absence of an undercut are properties of the pair. Basis: First article seated in the countersink. |
Torx machine screws are headed on single-die machines that form the countersunk cone and the six-lobe recess in one stroke, rolled with the machine thread and passivated as a batch. The first part of every run is measured on head diameter, cone angle, head thickness, recess depth and thread.
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Cutting six lobes into the small flat top of a countersunk head is the step that sets the life of the part. The punch has to reach full depth across a face that is only a few millimetres wide, and the metal left between the recess floor and the cone is thin enough that a small error in the punch shows up as a head that splits at the rim rather than as a dimension that drifts out of tolerance.
On Torx machine screws the cone is formed before the recess and its angle is set by the die. Wear on the die changes the cone angle slowly, and a cone that is slightly off angle no longer sits fully in the countersink, so the screw reads as proud on a panel even though every dimension is inside tolerance. The angle is checked against a master at the start of each run for that reason.
What decides whether Torx machine screws pass is the cone, the recess, the head thickness and the thread. The inspection agreement covers those, and the criteria come from the drawing.
Cone and recess on the projector |
Thread and start checked |
Core hardness checked |
Salt-spray testing of the grade |
Cone angle is measured against a master and proved on a countersink block, and the head thickness is checked in the same pass, because the recess depth is only meaningful against it. The recess is measured for lobe form and depth and then proved with the production key.
A sample from every batch is driven into the customer’s tapped part at the joint torque and removed. On a small star screw the removal check is what matters: a recess that takes the driving torque and reams on the way out has failed, and a flush head leaves nothing to grip if it does.
Every batch is traceable to the wire it was made from and to the passivation batch that finished it. The grade and heat number appear 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 shipment we supply the material certificate, the inspection record for the dimensions on the drawing and, where the grade is listed, the third-party report that covers it. The documents carry the drawing revision and the batch number, so a repeat order keeps the same recess and the same cone.
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 Torx machine screws the first article is driven with the key the line actually uses, because a star recess is only proven against a real key. Buyers visit during the process to review samples.
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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 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 |
The T-size that matches the screw diameter, named on the drawing. A key one size small seats part way and then reams the lobes.
The key drives on the lobe walls and does not lift out, so a small head can be opened many times without the drive rounding.
In a matching countersink, yes. This version has no undercut, so a slight transition radius can hold it a fraction proud in a square-cut seat.
Yes, with a Torx screwdriver. The key should be replaced when it shows wear, because a worn key damages the recess.
A2 covers rain and condensation, A4 covers chlorides. With no coating, the recess stays as formed.
Head diameter, cone angle and thickness, Torx T-size and depth, thread pitch and overall length.
How a Torx machine screw project runs from drawing to repeat delivery:
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1
Send the drawing and the countersink
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→ |
2
Torx size, cone and thread agreed
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→ |
3
First article driven with your key
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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, cone angle and thickness, the Torx T-size and recess depth, thread pitch and overall length.
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Head diameter
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Cone angle
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Torx size
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Recess depth
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Thread pitch
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Overall length
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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
