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+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:Phillips Truss Head Screw, Stainless Steel
Materials:Stainless Steel
Surface treatment:Plain
Head Type:Truss Head
Drive:Phillips Cross
Thread:Machine Thread
Point:Blunt
Forming:Single Die Heading
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:503
We make Phillips truss head screws in passivated stainless, a wide shallow head with a cross recess and a machine thread, quoting them from M1 to M14. Head diameter, thread, grade and the insert behind the panel are agreed up front, and the first article is fitted 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.
A Phillips truss head screw is a machine screw with a very wide, shallow head and a cross recess. On this item the material is passivated stainless and the thread is a machine thread, so the fixing needs a tapped hole, a nut or an insert behind the panel. The wide head carries the clamp load and covers the hole; the thread holds. The family is quoted from M1 to M14 with Number 503.
Truss head. A wide, shallow dome with a flat bearing face, giving the largest bearing ring of the common low heads.
Cross recess. A Phillips recess with tapered walls, sized to cam out before the head is destroyed.
Machine thread. A rolled thread for a tapped hole or a nut, ending in a blunt chamfer — it does not cut its own thread.
Passivated stainless. No coating, so the head and the thread are as made and the alloy carries the protection.
A Phillips truss head screw does its work on two faces that are not equally visible. On the outside there is a wide, smooth dome that spreads the load and looks like a deliberate fitting. On the inside there is a nut, a weld nut or a rivet nut that nobody ever sees — and the reason the wide head matters is that it makes the outside of the joint independent of how well that insert was installed.
That is the practical case for the form. A truss head covers a hole that is slightly oversize, a weld-nut spatter ring, or a rivet-nut flange that did not sit perfectly flat; a smaller head would leave those details on show. Where the panel is thin and the thread is in an insert behind it, the head is doing the cosmetic work and the insert is doing the structural work, and neither has to be perfect for the joint to look right.
On a Phillips truss head screw the machine thread is the other half of that arrangement. Because it does not cut its own thread, the panel can be as thin as the design wants without the fixing dictating a minimum thickness; the load goes into the insert, not into the sheet. This is the opposite trade from a self-tapping truss head, where the sheet itself has to carry the thread.
On a Phillips truss head screw the wide bearing ring still has to be considered. On a thin panel a truss head spreads the load over several times the area of a pan head, so the sheet does not dimple under tightening; but the ring is a narrow annulus and it does not tolerate a panel that is domed around the hole. Where the panel is distorted, the head rocks and the joint looks tight while it is not.
Stainless is the finish and the protection at once. There is no coating to chip at the rim or to wear in the recess, and a passivated stainless truss head in a wet or outdoor joint keeps both its appearance and its thread for as long as the equipment it is fitted to.
The recorded range is M1 to M14, covering M1, M2, M3, M4, M5, M6, M7, M8, M9, M10 and M14. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission. For a Phillips truss head screw the quotation carries head diameter and height, recess size, thread size and length, the grade and the finish, because the head covers the hole and the thread has to suit the insert behind it.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Truss head, wide and shallow | Head diameter and height |
| Recess | Phillips cross | Recess size and depth |
| Thread | Machine thread | Pitch and length, gauged per batch |
| End | Blunt, chamfered | Chamfer cut, not deburred |
| Finish | Passivated stainless | Surface condition and film |
| Length | Under the head | Measured on the shop plate |
Head diameter should be quoted against the hole it has to cover. A truss head is wide, but not infinitely so, and a hole enlarged by a repair or a badly punched insert can exceed it; where that is likely, the next size up or a flanged head is the better answer.
The thread should be quoted against the insert rather than the panel. A machine thread in a rivet nut has a defined engagement, and a screw that is too long will bottom in the insert before the head seats — a failure that reads as a stripped thread and is really a length problem.
Three features define this part: the wide head, the cross recess and the machine thread. The first spreads load and covers the hole, the second is a drive any workshop can use, and the third moves the structural work to an insert behind the panel.
| Feature | What it gives | What it costs |
|---|---|---|
| Wide truss face | Load spread, covers the hole | Thin rim, easily bent |
| Cross recess | Common driver, defined cam-out | Cam-out marks a visible head |
| Machine thread | Thin panel needs no thread of its own | Needs a nut or a tapped insert |
| Passivated stainless | No coating to wear or chip | Galls against stainless |
| Low dome | Nothing to catch | Little height for the recess |
On a Phillips truss head screw the wide face is what a customer sees and what a designer specifies, and it is worth checking it against the panel rather than accepting it. A truss rim that overhangs the edge of a narrow panel looks wrong and protects nothing; a rim that is well inside the panel gives the joint the even bearing it was chosen for.
On a Phillips truss head screw the cross recess is the part that gets used. On a wide shallow head there is not much height for a recess, so a Phillips bit has to be in good condition; a worn bit cams out early and marks the face. Where the joint is on show and will be serviced, a star drive is the better choice in the same head.
The recorded finish is passivation with no coating. On a truss head that is right: the wide face is what everyone sees, and a coating would wear at the thin rim and at the recess, leaving bright patches on the two most visible features. Passivation leaves the surface as made and lets the alloy resist corrosion on its own.
| Option | How it protects | Effect on head and thread | Typical use |
|---|---|---|---|
| A2 stainless, passivated | Passive chromium oxide film | As made | Outdoor and general panels |
| A4 stainless, passivated | Passive film with molybdenum | As made | Coastal and chemical |
| Steel, white zinc | Sacrificial zinc | A few microns; fit re-checked | Indoor painted panels |
| Steel, black zinc | Sacrificial zinc, dark | A few microns; fit re-checked | Dark equipment |
| Aluminium, anodised | Hard oxide layer | Coating changes the recess fit | Lightweight panels |
On Phillips truss head screws the choice between A2 and A4 follows the environment. A2 handles ordinary outdoor exposure; A4 is the answer where chlorides are present, which on a thin panel means coastal installations or washdown lines where the joint stays wet.
Where Phillips truss head screws go into a dry indoor panel, a zinc-plated version is cheaper and behaves the same in the joint. The stainless version is chosen for its life outdoors, not for its strength, and the two should not be confused on the drawing.
Three assemblies where Phillips truss head screws are the fixing:
| Where it sits | The screw clamps a thin sheet where the thread is in a weld nut or a rivet nut and the wide head has to cover the insert’s flange. |
| When it goes wrong | A hole enlarged by the insert or a repair exceeds the head, and the joint exposes its hardware. |
| Why it happens | The panel is thin, the thread is in an insert, and the face is visible. |
| What we control | Head diameter against the hole checked, first article fitted to the panel. |
| Where it sits | The screw closes a cover where the panel is exposed and the fixing has to survive weather without a coating. |
| When it goes wrong | A plated head rusts at the rim, and a bent truss rim reads as damage. |
| Why it happens | The joint is wet, the face is on show, and the part is stainless. |
| What we control | Grade confirmed, head and recess checked, passivation inspected. |
| Where it sits | The screw holds a plate where a wide head reads as a deliberate fixing rather than a small fastener. |
| When it goes wrong | Over-driving bends the thin rim, and a cam-out marks a visible face. |
| Why it happens | The fixing is visible, it is low, and the panel is thin. |
| What we control | Face flatness and recess checked, first article reviewed on the plate. |
Four reasons that matter on a wide-headed machine screw, each tied to what the drawing has to prove:
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Head against the hole and the insert
The head diameter, the hole and the insert behind it are confirmed together, because the truss face has to cover the hardware that the thread depends on. Basis: Head, hole and insert agreed. |
Head, recess and thread in one route
The wide head and the cross recess are formed in the heading stroke, the thread is rolled and the parts are passivated in the same route. Basis: One route from wire to passivated screw. |
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Face flat, recess driven
The first article is checked for face flatness and the recess is driven with the production bit, because a thin rim and a shallow recess are the two features that fail first. Basis: First article driven and checked. |
First article fixes the setting
The first article fixes the wire, the head die and the passivation; repeat orders are compared against that record. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these Phillips truss head screws from stainless wire on single-die headers that form the wide shallow head and cut the cross recess in one stroke, rolls the machine thread to a blunt chamfered end and passivates the finished parts. The first part of every run is measured on the head and rim, driven with the production bit and entered into a thread gauge before the batch continues.
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On a Phillips truss head screw the wide head leaves a thin rim, and the rim is where the die shows wear. A worn die gives a rim that is thinner still, or a face that is very slightly conical, and either way the head seats on its edge instead of on the face. The part still looks like a truss head in a tray, which is why the face flatness is measured at the start of every run.
What decides whether Phillips truss head screws pass is the head, the rim, the recess and the thread. The inspection agreement covers those, and the criteria come from the drawing.
Head and rim on the projector |
Thread gauged per batch |
Hardness checked on the wire |
Salt-spray testing of the grade |
On Phillips truss head screws the head is checked for diameter, height and face flatness, and the rim for bends and thickness. The recess is checked for depth and driven with the production bit, and the thread is gauged per batch. The alloy is confirmed on the certificate rather than judged by appearance.
A salt-spray sample is run where the environment asks for it. On a truss head the rim is the thinnest section, so it is the first place a result shows — and the first place a bend would be noticed in service.
Every shipment of Phillips truss head 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 a repeat order is made from the same grade and the same head geometry that were approved.
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 wide-headed part the first article is fitted into the customer’s panel and insert, because the seat is the function. Buyers visit during the process to review samples and to see how the parts 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 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 |
No. It has a machine thread, so it needs a nut, a tapped hole or an insert behind the panel. The truss head version with a tapping thread is a different part.
It spreads the clamp load on a thin panel and covers the insert flange or a slightly oversize hole on the visible side.
A2 for general outdoor exposure and A4 for coastal or chemical conditions. Both are passivated; the difference is the alloy.
Under the head. A screw that bottoms in a rivet nut before the head seats reads as a stripped thread and is usually a length error.
It can, on over-driving or on a seat that is not flat. The rim of a wide shallow head is the thinnest section of the part.
Thread size and length, head diameter and height, recess type, the grade, and the hole and insert dimeters it has to cover.
How a Phillips truss head screw project runs from drawing to repeat delivery:
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1
Send the drawing and the panel with its insert
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→ |
2
Head, thread and insert agreed
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→ |
3
First article fitted into your 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 thread size and length, the head diameter and height, the recess type, the grade and the insert or nut the thread will engage.
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Thread size
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Length
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Head diameter
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Head height
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Recess type
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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
