Tel：
+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:Black Torx Screws Large Head Six Lobe Self Tapping Screws
Materials:Carbon Steel
Surface treatment:Black Zinc Plated
Head Type:Large Head
Drive:Torx
Thread:Self Tapping
Point:Blunt
Forming:Multi-Station Heading
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:541-1
We make black torx screws from carbon steel with a large flat head, a six-lobe recess and a self tapping blunt point, black zinc plated and quoted from M1 to M14. Head diameter, recess size, point and plating come from your drawing, and the first article is driven into your own panel.
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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.
Black torx screws are self tapping screws with a six-lobe star drive and a dark zinc finish, made with an oversized flat head that spreads load without a washer. The recorded item on this page is carbon steel with a black zinc plate, a large flat head and a blunt point, quoted from M1 to M14 with Number 541-1.
Large flat head. A wide disc with a shallow dome, much broader than the thread size would normally carry. It bears on soft panels, plastic and thin sheet where a standard head would sink or dimple.
Torx drive. Six curved lobes, driven with a matching star bit. There are no internal corners for the bit to round off, and the drive does not cam out, which on a wide thin head is what keeps the recess usable.
Self tapping thread. A coarse thread with a sharp crest that forms its own way into a drilled or punched hole, with a blunt point at the end.
Black zinc. Electroplated zinc with a dark passivation. It is sacrificial like any zinc, and the dark tone is what lets a black torx screw disappear into a black housing instead of reading as a bright dot on the panel.
On a black torx screw the head is much wider than the shank, and that ratio is the engineering problem. A large flat head on a small thread means the load arrives at a diameter far outside the shank, so the material between the head and the shank has to turn the load through a tight radius. If the radius is wrong or the material flow is poor, that is where a head pops off in service.
That is why this family is made on multi-station headers rather than single-die ones. A single blow would try to spread a large head in one go, which leaves the material around the head-to-shank junction stretched and thin; a progressive sequence forms the head in stages, so the fibres follow the shape and the radius stays full. On a black torx screw with a big head, the forming route is part of the strength.
The Torx recess is formed in the same sequence. Its lobes are curved, and the drive contacts the flanks rather than corners, so the same head height carries more torque than a cross would. That matters here because a wide head is deliberately thin: a cross in a head this shallow cams out almost immediately.
The thread is rolled from under the head to a blunt point. On this family the point is blunt because the hole already exists — drilled, punched or moulded — and the thread forms against it. A sharp point would try to pierce a plastic boss and split it.
Black zinc goes on after the thread is rolled. It adds a few microns over the head, the lobes and the thread, and on a shallow recess that is measurable. The first article is therefore driven with the production bit in the plated condition, and the plating thickness on the drawing is read as a working tolerance.
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 black torx screw the head diameter is a functional dimension because it is the bearing area, and it is quoted independently of the thread size.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Large flat head, wide disc | Diameter, height and face flatness |
| Recess | Torx, six lobes | Lobe width and depth, bit tried after plating |
| Thread | Self-tapping, coarse, full length | Gauged per batch after plating |
| Point | Short taper, blunt tip | Checked on the first article |
| Plating | Black zinc, dark passivation | Thickness range and salt-spray sample |
| Length | From under the head to the point | Measured on the shop plate |
Head diameter is chosen from the material it bears on. In a plastic housing the head has to be wide enough that the clamp load stays below the creep strength of the boss; in thin sheet it has to reach past the deformed zone around the hole. Too small and the panel dimples; too large and the head fouls a rib or a neighbouring feature.
Because black torx screws are often short, the length is measured from under the head and the thread runs full length. A short screw with a partial thread would leave the plain shank inside the boss doing nothing, which is why this family is normally fully threaded even though other pan head screws in the mill are not.
Three features define a black torx screw: the wide head, the star drive and the dark finish. Each one solves a different problem, and the combination is what makes the screw work on a visible plastic or painted panel.
| Feature | What it gives | What it costs |
|---|---|---|
| Large flat head | Bearing area without a washer | Head is the weak point if the radius is poor |
| Torx drive | High torque, no cam-out | Needs the matching star bit |
| Self-tapping thread | Holds without a nut or tapped hole | Needs the right pilot hole |
| Black zinc | Hides in dark panels | Thin film; wears at the recess edge |
| Multi-station forming | Full radius and sound head | A longer, more tooled route |
The drive is what makes the wide head usable. A cross in a head this thin would cam out long before the joint was tight, and every cam-out scores the recess. A star drive transmits the torque through the flanks, so the same head can be driven to a defined torque without the bit walking out — which is also what allows the head to stay as thin as it is.
The finish is a choice about what the customer sees. On a black housing a bright zinc head is a visible dot on every panel; a black torx screw reads as part of the moulding. The trade is that black passivation wears at the recess edge first, so a screw that has been driven a few times shows a bright ring where the bit sat.
Black torx screws carry a black zinc finish with a dark passivation, applied after the thread is rolled. It is a sacrificial coating: where it is scratched the zinc around the scratch corrodes first and the steel underneath stays covered, which is the property that makes it the default for indoor fixings.
| Finish | How it protects | Effect on recess and thread | Typical use |
|---|---|---|---|
| Black zinc | Sacrificial zinc, dark passivation | A few microns; recess re-checked | Dark housings and panels |
| White zinc | Sacrificial zinc | A few microns; recess re-checked | General indoor work |
| Black oxide | Thin conversion film, oiled | Almost no change | Unseen dark joints |
| Dacromet | Zinc-aluminium flake layer | Film builds; recess re-checked | Outdoor and damp service |
| Nickel plate | Hard barrier deposit | Thicker; recess re-checked | Visible decorative fixing |
On a wide head the finish is judged on a large area, so an uneven deposit shows. Barrel plating is even enough on a small part, but a head this size has to be racked or tumbled for long enough that the face does not come out patchy, and the sample is approved as a colour sample rather than only as a dimension.
The limit is corrosion. A thin zinc film outdoors is consumed quickly, and the head, being wide and flat, holds water on its face. Where the joint is exposed, the answer is a flake coating or a different base metal rather than a thicker coat of the same finish.
Three assemblies where a black torx screw with a large head is the fixing of choice:
| Where it sits | The screw fixes a plastic panel, a trim strip or a cover where the head sits on a visible moulded surface and a small head would dimple it. |
| When it goes wrong | A narrow head pulls into the plastic, leaving a crater that cannot be dressed; a bright head shows as a spot on a black panel. |
| Why it happens | The panel is moulded, the fixing is visible, and the joint is serviced. |
| What we control | Head diameter and face flatness checked, recess driven with the production bit. |
| Where it sits | The screw closes a housing or mounts a board where the head has to stay inside a narrow border and the drive has to be driven to a repeatable torque. |
| When it goes wrong | A cross recess cams out and marks the case; a head that is too wide fouls the seam. |
| Why it happens | The housing is small, the torque is set, and the fixing repeats. |
| What we control | Recess checked with the production bit after plating, head height held. |
| Where it sits | The screw fixes a bracket or a trim into board or a moulded part where the thread forms in the material and the head has to spread load. |
| When it goes wrong | A small head compresses the board, and a washer adds a part to handle on the line. |
| Why it happens | The material is soft, the fixing is visible, and the joint is made once. |
| What we control | Point form and thread checked against a sample of the board. |
Four reasons that matter on a wide head with a star drive, each tied to what the drawing has to prove:
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Head, radius and drive reviewed together
The head diameter, the radius under it and the recess size are reviewed as one set, so a head that would shear or a recess that would tighten after plating is raised before the tools are set. Basis: Head, radius and drive reviewed as one set. |
Multi-station forming for a wide head
The head is formed progressively rather than in one blow, so the material follows the shape and the radius under the head stays full. Basis: Progressive forming, full radius under the head. |
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Recess and head checked after plating
The recess is driven with the production bit in the plated condition, and the head face is checked for flatness on the first article. Basis: First article checked after plating. |
First article fixes the setting
The first article fixes the wire heat, the forming stations, the thread roll and the plating; repeat orders are compared against that record. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these black torx screws from carbon steel wire on multi-station headers: the head is upset in stages, the six-lobe recess is formed in the final blow, the thread is rolled to a blunt point and the parts are black zinc plated. The first part of every run is measured on the head, driven with the production bit and driven into a sample of the customer’s material before the batch continues.
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The station that forms the transition between head and shank is the one that decides whether the part survives. A radius that is too tight leaves a notch, and a notch under a wide head is where a crack starts when the screw is driven hard. Because the head is formed in stages, that radius can be kept full and checked on the section of the first article rather than assumed from the die drawing.
What decides whether black torx screws pass is the head, the radius under it, the recess, the thread and the plating. The inspection agreement covers those, and the criteria come from the drawing.
Head and recess on the projector |
Thread gauged after plating |
Hardness testing against the property class |
Salt-spray testing of the black zinc plate |
The head of a black torx screw is checked for diameter, height and face flatness, and the radius under it is checked on the section of the first article. That section is the only place the radius shows: on the outside a wide head looks sound whatever is happening underneath it.
The recess is checked for lobe width and depth and then driven with the production bit. On a shallow head this is the decisive check, because a few microns of coating or a worn punch shows up as a bit that rocks rather than as a dimension out of tolerance.
The thread is gauged after plating, and the driving torque is measured in the customer’s material. A wide head driven into a plastic boss strips the boss rather than the screw, so the torque is set from the boss and the check is made on the material the joint will actually see.
Every shipment of black torx 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 material or the plating. The documents carry the drawing revision and the batch number, so the paperwork can be matched to the parts.
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 visible black head the first article is also the colour sample, so a batch that is on size and wrong in tone is caught before it ships. Buyers visit during the process to review samples and to see how the heads are formed.
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8,678+
customers served
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87%
of orders from repeat customers
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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 |
The star transmits torque through the flanks and does not cam out, which matters on a wide thin head where a cross would slip and score the recess.
To spread the clamp load on soft plastic, board or thin sheet without a washer. The head is the bearing area, so its diameter is a functional dimension.
Only if the radius under the head is poor or the torque is beyond what the head can take. The family is formed in stages so that radius stays full, and the first article is sectioned to prove it.
A blunt point for a drilled, punched or moulded hole. It starts in the hole and forms its own thread; it does not pierce the material first.
For indoor equipment it is. The dark passivation wears at the recess edge first, and in wet service the thin zinc layer is consumed quickly.
Head diameter and height, recess size, thread size and type, point form, length and datum, material and plating thickness.
How a black torx screw project runs from drawing to repeat delivery:
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1
Send the drawing or the panel sample
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→ |
2
Head, radius and recess review
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→ |
3
First article driven into your material
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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, the recess size, the thread size and type, the point form, the length and datum, and the material and plating.
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Head diameter
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Head height
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Recess size
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Thread and type
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Point form
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Length and plating
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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
