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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:Stainless truss head machine screw (combination drive)
Materials:Stainless Steel
Surface treatment:Plain, passivated
Head Type:Truss head
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Drive:Combination Phillips and slot
Thread:Machine thread, right hand
Forming:Cold heading; thread rolled, then passivated
Number:513
We manufacture stainless steel truss head machine screws with a wide head, a combination cross-and-slot drive and a machine thread, quoted from M1 to M14 in a plain passivated finish. Head diameter, drive, thread and grade 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.
A stainless steel truss head machine screw is a machine screw with a broad, shallow head and a stainless body, used where the head has to cover a large hole and the joint has to survive washing or weather. The recorded item on this page is a stainless screw with a truss head, a combination cross-and-slot drive and a machine thread, quoted from M1 to M14.
Truss head. A wide, shallow dome with a large flat bearing face. It covers more of the panel than a pan head at the same thread size, which is what makes it useful over oversized, slotted or punched holes and on soft or thin material.
Stainless body. The alloy carries the corrosion resistance, so there is no coating to chip at the head edge or to wear off the bearing face — which matters on a head that is deliberately wide and exposed.
Combination drive. A cross recess with a slot cut through it, so the screw can be driven with a Phillips bit on a line or a flat blade during service.
Machine thread. The thread engages a tapped hole, a nut or an insert, so the joint is designed around the mating thread rather than the screw forming its own.
Together these decide the joint: the wide head covers the hole, the stainless body survives the wash, the combination drive matches the tool at hand, and the machine thread holds the clamp. That is why a stainless steel truss head machine screw is specified by head diameter, drive, thread and grade together.
The body of this stainless steel truss head machine screw is stainless wire, with the grade and heat number kept with the batch record. 304 is the default for indoor and food-side work; 316 is specified where chlorides are present, and the grade is what decides how the joint looks after a year of washing.
The truss head is formed in one heading operation. The wide diameter is the reason for the part, and a head that size has to be formed without thinning at the rim, or it dishes when the joint is tightened. The bearing face is held flat for the same reason.
The combination recess is formed in the same operation. The cross and the slot share the head material, so the walls between them are the thinnest part of the drive; forming rather than cutting keeps those walls supported.
The machine thread is rolled over the full length. Rolling keeps the grain continuous and leaves no burr at the end, which matters here because the truss head is often used over a slotted hole where a burr would catch on the panel edge.
The parts are passivated after forming. Passivation removes free iron from the surface and restores the chromium oxide film, and it adds nothing to the head face or the recess, so the screw seats and drives as it was measured.
Stainless steel truss head machine screws of this type are quoted from M1 to M14; the recorded configuration covers that range in stainless with a plain finish and a combination drive. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission, because the head and the thread are set before the tooling is made.
| Item | How it is defined | What we control |
|---|---|---|
| Head diameter | The wide truss face that covers the hole | Checked on the projector on the first article |
| Head height | The shallow dome profile | Measured from the bearing face |
| Drive | Combination cross and slot | Checked with a PH bit and a flat blade |
| Thread size and pitch | The fit in the tapped hole | Gauged per batch |
| Length | From under the head to the tip | Datum stated on the drawing; measured on the shop plate |
| Grade | The stainless the part is made from | Confirmed against the material certificate |
Each size is quoted against the hole it covers. The head diameter, the hole diameter and the panel thickness are reviewed together, because the truss head is chosen precisely for a hole that is larger than the thread.
Length is measured from under the head and the head height is stated separately, because on a truss head the dome is part of what the customer sees and measures.
The wide head is a coverage feature, and on a stainless part it is also an appearance feature. A truss head covers a punched hole that a smaller head would leave exposed, and because the finish is metal rather than a coating, the head edge never shows a chip or a rust ring after the joint is washed.
| Feature | What it does on this part | What goes wrong without it | What we control |
|---|---|---|---|
| Head diameter | Covers oversized and slotted holes | A smaller head pulls through or leaves a ring | Set from the hole on the drawing |
| Bearing face flatness | Even contact under the head | The head rocks and the joint loosens | Checked on the first article |
| Combination drive | Either PH or flat blade drives it | One weak drive is worse than either alone | Checked with both tools |
| Material grade | Corrosion resistance in washing | Staining and pitting around the head | Confirmed on the certificate |
Stainless changes the assembly advice in two ways. It galls when it meets stainless, so the thread fit and the drive speed matter; and it work-hardens, so a thread that is forced into a damaged tapped hole takes material with it. The combination drive helps on both counts, because a flat blade can usually break a seized screw free where a Phillips bit would cam out.
The truss head and the machine thread are complementary on a serviced panel. The thread lets the screw come out and go back without damaging the hole, and the wide head covers any deformation the panel picked up around the hole while it was open — which is often why the head is specified wider than the catalogue size.
The finish is not a coating, and that is the point. A plated truss head shows a bright ring as soon as the plating wears at the edge; a passivated stainless head wears the same way as the panel around it, so the joint ages consistently.
This stainless steel truss head machine screw is supplied plain and passivated. The passive film is the protection, it reforms after a scratch, and it adds nothing to the head face or the recess, so the screw seats at the angle it was formed to and the driver engages to full depth.
| Finish | How it protects | Effect on head and recess | Typical use |
|---|---|---|---|
| Plain, passivated stainless | Passive film forms in air | No build-up; head and recess as formed | Wash-down, food and outdoor joints |
| Electropolished | Surface levelled, chromium enriched | A few microns removed; head re-checked | Visible stainless panels |
| Bead blasted | Uniform matte surface | No dimensional change | Panels where glare must be removed |
| Black oxide (stainless) | Chemical conversion, thin film | Minimal thickness; recess re-checked | Dark visible panels |
| Zinc plated (steel equivalent) | Sacrificial layer | Build-up on the head; seat re-checked | Steel truss screws indoors |
Salt-spray exposure is agreed per project and written on the drawing; plain stainless is tested in the condition it ships in. On a wide head the finish question is about the exposed bearing face as much as the thread, because that face is what the customer sees after assembly.
Packing protects the head faces and the recesses. The parts are bagged in counted quantities, labelled with the batch, the material heat and the grade, and packed so the wide heads cannot rub against each other.
Three assemblies where a wide head and a stainless body are specified together:
| Where it sits | The screw closes a guard, a chute or a panel where the hole is punched oversize and the joint is washed with chemicals every shift. |
| When it goes wrong | A plated head loses its coating in the wash and rusts into the panel, and a small head leaves the punched edge exposed where residue collects. |
| Why it happens | The equipment is washed on a schedule, the panels are stainless, and the fasteners are part of the hygiene inspection. |
| What we control | Grade confirmed on the certificate, the head face checked, and the thread gauged per batch. |
| Where it sits | The screw fixes a shelf bracket, a door fitting or a trim panel where the head sits on a visible stainless face. |
| When it goes wrong | A head that is too small leaves the hole showing on a brushed panel, and a coated head chips and stains around the edge. |
| Why it happens | The surfaces are visible, the joints are cleaned daily, and the fittings are replaced when they loosen. |
| What we control | Head diameter matched to the hole, bearing face flatness checked, and the first article assembled in a panel sample. |
| Where it sits | The screw holds a cover, a bracket or a sign where the joint sees rain and salt air and the head is exposed. |
| When it goes wrong | A steel screw rusts at the head and bleeds down the panel, and a wide head with a coating wears through at the edge first. |
| Why it happens | The joint is exposed, the panel is coated steel or stainless, and the assembly is expected to stay intact between services. |
| What we control | Grade matched to the panel, plain passivated finish checked, and the thread gauged per batch. |
Four reasons that matter on a wide-headed stainless part, each tied to what the drawing has to prove:
|
Head diameter reviewed against the hole
The truss diameter, the punched hole and the panel thickness are reviewed before tooling, so a head that would leave a ring is raised first. Basis: Head, hole and panel reviewed before tooling. |
Head and combination recess in one route
The wide head and the cross-and-slot recess are formed in one heading operation, so the recess stays centred in the bearing face. Basis: One heading operation for head and drive. |
|
Both drives and the thread checked on the part
The recess is checked with a PH bit and a flat blade, the head face on the projector and the thread with gauges, on the first article. Basis: First article checked with both tools. |
First article to repeat production
The first article fixes the drawing revision, heat number, die set and thread roll; repeat orders are compared against that record. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these stainless steel truss head machine screws on a heading machine that upsets the wide head and the combination recess in one operation, then rolls the machine thread and passivates the parts. The first part of every run is measured on the head face, driven with both tools and gauged on the thread, before the batch continues.
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Between runs the insert is changed to the drawing head and recess, and the thread rolls to the size; the first part goes to the projector, to both bits and to the gauges. Stainless work-hardens as it is rolled, so the rolls are set for the grade and the first part is checked before the run continues.
What decides whether a stainless steel truss head machine screw passes is the head diameter and height, the flatness of the bearing face, the recess in both drive configurations, the thread class and the grade. The inspection agreement covers those, and the criteria come from the drawing.
Head profile and recess on the projector |
Thread gauged per batch |
Hardness testing where the drawing requires it |
Salt-spray testing of the passivated part |
Each batch is recorded against the drawing revision: head and recess from the first article, the thread gauged per batch, and the grade confirmed on the certificate. If either drive or the head check fails, the parts back to the last good setting are held and re-checked.
Where a third-party report is required for the material, it is written into the drawing, the report ships with the parts and the label carries the same batch number as the inspection record.
Every shipment of stainless steel truss head machine screws is traceable to the wire it was made from. The grade, heat number and standard 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. 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 truss head the first article is offered up to the customer’s panel, so the head diameter and the punched hole are signed off together. 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 inspection room 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 |
It is a machine screw with a broad, shallow head and a stainless body. This one has a combination cross-and-slot drive and a machine thread, quoted from M1 to M14 in a plain passivated finish.
Because it covers more of the panel. A truss head bridges oversized, slotted or punched holes and spreads the load on thin or soft material without a washer.
Yes. The thread is a machine thread and engages a tapped hole, nut or insert. A truss head with a self-tapping thread is a different part.
304 covers indoor and food-side work; 316 is the choice where chlorides are present, such as coastal or chlorinated wash-down service. The grade is what decides how the head looks after a year.
Plain and passivated, with no coating. The passive film is the protection, and on a wide head it means the edge never shows a chipped coating or a rust ring.
Head diameter and height, drive type and size, thread size and pitch, length and datum, material and grade, finish, and the hole the head has to cover.
How a stainless steel truss head machine screw project runs from drawing to repeat delivery:
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1
Send the drawing or sample
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→ |
2
Head, hole and grade review
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→ |
3
First article on the 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 diameter and height, drive type and size, thread size and pitch, length and its datum, material and grade, finish, and the hole the head has to cover.
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Head diameter and height
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Drive type and size
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Thread size and pitch
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Length and datum
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Material and grade
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Hole to be covered
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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.
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