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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:Black Phillips Truss Washer Head Screw, serrated anti-slip, self-tapping (Non-Standard)
Materials:Carbon Steel
Surface treatment:Black oxide (blued finish)
Head Type:Truss Washer Head - wide bearing flange with integral serrations
Drive:Phillips cross recess (#2)
Serration:Angular teeth on the underside of the washer flange, for anti-slip locking
Thread:Self-tapping, thread-cutting, 60 deg; flat (blunt) tail, no drill point
Point:Flat tail (blunt); cuts its own mating thread, stops flush
Forming:Single-die cold heading (head + flange + serrations), thread rolling, black oxide, sort and inspect
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14 (custom)
Number:279
We manufacture black phillips truss washer head screws: a wide truss head with an integral serrated washer flange, a #2 Phillips recess, a self-tapping thread and a flat blunt tail, black oxide finished. Head and flange, serrations, thread and length are taken from your drawing.
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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 phillips truss washer head screws are self-tapping screws with a wide truss head that carries an integral washer flange, a Phillips cross in the crown and angular teeth on the underside of the flange. The recorded item on this page is carbon steel with a black oxide finish, a #2 Phillips recess, a thread-cutting self-tapping thread and a flat blunt tail, with Number 279.
Truss washer head. The head is wide and low, and the washer flange is part of it rather than a separate ring. That gives the bearing area of a washer with the part count of one, and it is why black phillips truss washer head screws are used where a small head would sink into the panel.
Serrated flange. The underside of the flange carries angular teeth. They bite the mating surface as the screw seats, which is what makes the joint resist loosening under vibration — and what leaves a ring of marks on a soft or painted face.
Phillips #2. A cross recess sized for the common #2 driver, with the tapered wings that cam out before the head is destroyed. On a black finish the recess is where a worn bit shows first, as bright metal showing through the oxide.
Self-tapping, flat tail. The thread cuts its own mating thread in a prepared hole, and the tail is flat rather than pointed so the screw stops flush with the surface it enters instead of driving past it.
Black oxide. A thin conversion finish that darkens the steel. It is there for the look, for a dark assembly where bright screws would stand out, and it keeps the head and flange dimensions unchanged.
The head, the washer flange and the serrations are formed in one cold-heading stroke. Forming the teeth rather than milling them is what keeps the flange flat and the teeth continuous around the ring; a milled serration leaves burrs at the end of each cut and a land between teeth that does not bite.
The Phillips recess is formed in the same stroke, so it stays concentric with the shank and with the flange. If the recess is cut afterwards, the cutter can run slightly off and the driver then tips the head, which on a wide flange shows as a lifted edge on one side.
The thread is rolled after heading and runs up to the flange. Rolling work-hardens the steel and leaves a clean flank for a thread-cutting screw, and the thread is what does the cutting work in the prepared hole. The tail is left flat and blunt, with a small break, because the screw is meant to stop when the flange seats.
Black oxide follows the rolling. The treatment is a conversion layer rather than a deposit, so the thread, the recess and the serrations keep their dimensions; the parts are lightly oiled before packing, because the oxide film on its own is not a corrosion barrier.
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, and custom sizes on request. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission; on black phillips truss washer head screws the lengths are normally short, because the head and flange already do most of the work.
| Item | How it is defined | What we control |
|---|---|---|
| Head diameter | Truss head, wide and low | Checked on the projector |
| Flange diameter | Integral washer, wider than the head crown | Measured on the first article |
| Flange thickness | Set against the serration depth | Checked on the section |
| Serrations | Angular teeth under the flange | Checked for continuity on the first article |
| Recess | Phillips #2 | Driven with the production bit |
| Thread | Self-tapping, thread-cutting | Gauged per batch |
| Length | From under the flange to the tail | Measured on the shop plate |
Length is measured from under the flange, which is the surface that bears on the panel. That is not the same as measuring from the crown: the flange adds its own thickness, and on a screw of this type the flange thickness is also where the serrations sit. A drawing that quotes crown-to-tip length will fit a shallower stack than the drawing intends.
Flange diameter decides both the bearing area and the mark the screw leaves. A wider flange spreads the load further and covers a larger clearance hole, but it also leaves a wider ring of serration marks, which matters on a visible or painted face.
The three features that define this part are all about how it seats, and each of them does something the others cannot.
| Feature | What it gives | What it costs |
|---|---|---|
| Integral washer flange | Bearing area without a loose washer | No washer to change or upgrade |
| Angular serrations | Grip that resists loosening | Marks soft or painted surfaces |
| Phillips #2 recess | Standard driver, cams out before damage | Recess is the first thing to wear on a dark finish |
| Thread-cutting thread | Forms its own mating thread | Needs the right pilot hole |
| Flat blunt tail | Stops flush; cannot drive past the surface | Cannot start its own hole |
The washer flange is the feature buyers ask for when a plain truss head has dished a thin panel. Because the flange is part of the head, the load path is short and there is no risk of the washer being left off on the line. The trade is that a damaged flange means replacing the screw rather than the washer.
The serrations are a locking feature with a surface cost. On steel they bite and hold; on aluminium, plastic or a painted face they cut a ring that stays visible. Where the face must stay unmarked, the same part is specified without serrations rather than being fitted with a protective washer that defeats the grip.
The flat tail is what makes the screw stop. A pointed self-tapping screw can drive on until it breaks out of the far side; a flat tail stops when it runs out of hole, which on a panel with a defined thickness is exactly what is wanted. It also means the screw cannot start its own hole, so the pilot diameter in the drawing matters.
The recorded finish is black oxide, a blued surface with a light oil film. It darkens the steel without adding a measurable layer, which is why the recess, the serrations and the thread stay at their formed dimensions.
| Finish | How it protects | Effect on serrations and thread | Typical use |
|---|---|---|---|
| Black oxide, oiled | Thin conversion film plus oil | Almost no change | Dark indoor assemblies |
| Black zinc | Zinc layer with a black passivation | A few microns; gauged after | Dark parts that see moisture |
| White zinc | Sacrificial zinc, blue-white passivation | A few microns; gauged after | General indoor work |
| Dacromet | Zinc-aluminium flake layer, cured | Thin film; serrations re-checked | Outdoor and wet assemblies |
| Stainless (equivalent part) | Alloy provides protection | No coating | Wash-down and coastal work |
Black oxide is not a corrosion barrier on its own. It looks right in a dark assembly and it protects the part in dry indoor air as long as the oil film is intact, but a black phillips truss washer head screws part used outdoors or in a damp workshop will rust at the serrations first, because that is where the film is thinnest and where water sits.
Where a black part has to survive moisture, black zinc is the usual step up: it still reads as black, but the protection is sacrificial rather than a conversion film. That change also adds a few microns, so the thread is gauged after plating and the serrations are checked to make sure the teeth have not been rounded.
Three assemblies where a wide dark head with a locking flange is the right fixing:
| Where it sits | The screw closes a cover or fixes a module to a black chassis, where the head has to disappear into the finish and the flange has to spread the load on a thin panel. |
| When it goes wrong | A bright screw stands out against black, and a small head dishes the panel and shows a ring around the fixing. |
| Why it happens | The panel is thin and dark, the fixing is visible, and the assembly is opened for service. |
| What we control | Flange diameter and serration continuity checked, recess driven with the production bit. |
| Where it sits | The screw fixes a trim panel, a bracket or a cover where the fixing is close to a visible surface and vibration is constant. |
| When it goes wrong | A screw without a locking feature backs out under vibration, and a head that is too small pulls through the trim material. |
| Why it happens | The joint vibrates, the panel is composite, and the fixing is seen when the trim is removed. |
| What we control | Serration depth and flange flatness checked on the first article, thread gauged per batch. |
| Where it sits | The screw assembles a frame, a shelf bracket or a display fitting in a black finish, often assembled and taken apart repeatedly. |
| When it goes wrong | A dark part with a bright screw reads as unfinished, and a flange that is not flat rocks on the frame and loosens. |
| Why it happens | The structure is reused, the faces are black, and the fixing is in reach. |
| What we control | Flange flatness and serration continuity checked, black finish matched to the assembly. |
Four reasons that matter on a serrated washer head, each tied to what the drawing has to prove:
|
Flange and serration reviewed together
The flange diameter, flange thickness and serration depth are reviewed as one set, so a flange that would dish under torque is raised before the die is cut. Basis: Flange and serration reviewed as one set. |
Head, flange and teeth in one stroke
The truss head, the washer flange and the angular teeth are formed in one cold-heading stroke, so the flange stays flat and the teeth stay continuous. Basis: One stroke from wire to serrated head. |
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Flange and recess checked on the part
The flange is checked for flatness and the teeth for continuity, and the recess is driven with the production bit on the first article. Basis: First article driven with the production bit. |
First article to repeat production
A repeat order is measured against the first article, where drawing revision, wire heat, die set and thread roll were fixed. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these black phillips truss washer head screws on a single-die header that upsets the truss head, the washer flange and the angular serrations in one stroke and forms the #2 recess at the same time, then rolls the self-tapping thread to a flat tail. The parts are black oxide finished and oiled. The first part of every run is measured on the flange and the teeth, and driven into a sample panel, before the batch continues.
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The serrations are the part of the die that wears first. Worn teeth still look like teeth under a light but leave a shallower impression in the sample panel, and the joint they make loosens earlier. The die is therefore checked on the sample panel rather than only on the projector, and the check is repeated at the start of each run.
What decides whether black phillips truss washer head screws pass is the head, the flange, the serrations, the recess, the thread and the finish. The inspection agreement covers those, and the criteria come from the drawing.
Head and flange on the projector |
Thread gauged per batch |
Hardness testing against the property class |
Salt-spray testing where a coating is specified |
The flange is checked by driving the first article into a sample panel and then removing it. An even ring of tooth marks is a pass; a partial ring means the flange is not flat, and no measurement on the projector will show that as clearly. The same test shows whether the flange is dishing under the joint torque.
The recess is checked after the black oxide, because the oxide film on a dark part is thin and a shallow recess shows immediately as bright metal on the wings. On a black phillips truss washer head screws part the recess is the first place a customer notices wear, so it is checked with the blade and at the joint torque rather than by eye.
Every shipment of black phillips truss washer head screws is traceable to the wire it was made from. 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 finish. 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 serrated flange the first article is driven into a sample panel and removed again, because the bite and the flatness only show in the impression it leaves. 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
|
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 header and the finishing 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 |
A wide low truss head with the washer flange formed into it, so the bearing area of a washer comes with the screw and there is no separate part to fit or lose.
They bite the mating surface as the screw seats and resist loosening under vibration. They also leave a ring of marks, which matters on a painted or soft face.
No. It has a flat blunt tail, so it stops flush instead of driving past the surface. The pilot hole has to be drilled to size because the screw will not start its own hole.
It can. Black oxide is a thin conversion film, not a barrier coating, so it suits dry indoor assemblies. For damp or outdoor use a black zinc or Dacromet finish is the right choice.
A Phillips #2. The recess is formed with the head, so it is concentric with the flange; a worn bit will round the wings and show bright metal against the black.
Head and flange diameter, flange thickness, serration depth, recess size, thread type, length and datum, material and finish.
How a black phillips truss washer head screw project runs from drawing to repeat delivery:
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1
Send the drawing or sample
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→ |
2
Flange and serration review
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→ |
3
First article driven in a sample panel
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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 and flange diameter, flange thickness, serration depth, recess size, thread type, length and datum, material and finish.
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Head diameter
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Flange diameter
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Serration depth
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Recess size
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Thread type
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Length and finish
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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
