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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:Thread Forming Screws, Pan Head Phillips
Materials:Steel
Surface treatment:Black Zinc Plated
Head Type:Pan Head
Drive:Phillips Cross
Thread:Thread Forming Thread
Point:As Drawn
Forming:Single Die Heading
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:392
We make thread forming screws in black zinc plated steel, a pan head with a cross recess and a thread that displaces material instead of cutting it, quoting them from M1 to M14. Thread, point, head and pilot hole come from your drawing, and the first article is driven into your own material.
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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.
Thread forming screws are screws whose thread makes its own way into a hole by displacing material rather than cutting it away. The crest is rounded rather than sharp, the root is wider, and the hole is sized so the metal or plastic is pushed aside and flows into the thread form. This family is made in black zinc plated steel with a pan head and a cross recess, quoted from M1 to M14 with Number 392.
Forming thread. A thread with a rounded crest and a wide root, designed to displace material into the flanks instead of removing it.
Pan head. A low dome with a wide flat bearing face, the general-purpose machine head.
Cross recess. A Phillips recess with tapered walls, sized to cam out before the head is destroyed.
Black zinc. A dark sacrificial zinc deposit, thin enough not to change the thread form.
The thread is formed by displacement, so the material around the hole is worked rather than cut away.
Two families of screw are often lumped together as self-tapping, and they behave differently. A thread-cutting screw has a sharp crest and often a point that cuts a path: it removes material, and the removed material has to go somewhere. A forming screw has a rounded crest and no cutting edge: it pushes the material aside, and the displaced material becomes the thread that holds it.
The difference matters where the material cannot give up material. In a thin sheet a cutting screw thins the section it passes through and produces chips that stay inside the assembly; a forming screw keeps the wall thickness and produces no swarf. In plastic a cutting screw leaves a slot that can propagate into a crack, while a forming screw compresses the material around the thread and is stronger for it.
On thread forming screws the cost is the hole. A forming screw needs a pilot hole sized accurately: too small and the material cannot yield enough, so the boss splits or the sheet domes; too large and there is not enough material displaced to fill the thread, so the screw turns without holding. That window is narrower than for a cutting screw, and it is the number that decides whether the joint works.
On thread forming screws the thread form also sets the length. Because the thread is formed rather than cut, the first turn or two does most of the work of displacing material, and the torque peaks early. That is why a forming screw wants a steady driver rather than a fast one: speed does not help displace material, it only heats it or tears it.
Black zinc is the finish that suits the part. It is thin, so it does not close up the rounded crest that has to enter the hole, and it is sacrificial, so a scrape at the head does not start rust. Where the joint is exposed the stainless version of the same form is the right part, and the thread form does not change.
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 thread forming screws the quotation carries head diameter and height, thread size and pitch, the point form, the length and the material of the part they go into, because the hole is sized from the material as much as from the screw.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Pan head, flat face | Head diameter and height |
| Recess | Phillips cross | Recess size and depth |
| Thread | Forming thread, rounded crest | Pitch and major diameter, gauged |
| Point | As drawn for the application | Point form and thread start |
| Finish | Black zinc | Deposit thickness and adhesion |
| Length | Under the head | Measured on the shop plate |
Pilot hole size should be agreed with the screw, not taken from a table for a cutting screw. A forming screw in a hole sized for a cutting thread will split the material or dome the sheet, and the failure looks like a bad screw rather than the wrong hole.
Head diameter matters because a forming thread pulls harder on the material than a cutting one. A pan head spreads the load, but a pan head on a thin panel may still dimple if the hole is tight; a wider head or a flanged head is the answer where the material is soft.
Three features define this part: the forming thread, the pan head and the black zinc. The first is the reason for the family, the second is the seat, and the third is the finish that has to stay thin enough to let the crest enter the hole.
| Feature | What it gives | What it costs |
|---|---|---|
| Forming thread | No swarf, no thinned wall | Needs an accurately sized hole |
| Rounded crest | Compresses material rather than cutting | Higher driving torque than a cutting screw |
| Pan head | Load spread on thin panels | Stands above the surface |
| Cross recess | Common driver | Cam-out marks the head |
| Black zinc | Thin, dark, sacrificial | Wears at the head and the crest |
On thread forming screws the absence of swarf is worth more than it sounds in an assembly that is closed. A cutting screw leaves chips inside a housing where they can short a contact or block a mechanism; a forming screw leaves nothing behind. That alone decides the choice on equipment that cannot be cleaned after assembly.
On thread forming screws the narrow hole window is the price. Where the customer is drilling their own holes, the drawing should state the hole size and the material, and the first article should be driven into that material rather than into a test plate; the difference between a joint that holds and one that splits is often a few hundredths of a millimetre of hole.
The recorded finish is black zinc over carbon steel. On a forming thread the deposit matters because the crest has to enter the hole and push the material aside; a thick coating would change the effective diameter and raise the driving torque, and the crest is where the plate is scraped off as the thread forms.
| Option | How it protects | Effect on thread and recess | Typical use |
|---|---|---|---|
| Black zinc | Sacrificial zinc, dark | Thin; thread as plated | Dark equipment and housings |
| White zinc | Sacrificial zinc, trivalent | Thin; neutral tone | Indoor general work |
| Nickel plated | Barrier deposit, bright | Decorative; wears at the crest | Visible hardware |
| Dacromet | Zinc-aluminium flake layer | Thicker; hole and torque adjusted | Outdoor steel structures |
| Stainless, plain | Passive chromium oxide film | Thread as formed | Damp and outdoor |
On thread forming screws the choice of finish is usually driven by the housing rather than the joint. A black zinc screw disappears into a dark enclosure, which is why the finish appears on this part so often; a white zinc version is the same joint with a different appearance and slightly more forgiving corrosion behaviour.
Where the joint is exposed, neither zinc option is enough and stainless is the answer. A forming thread in stainless sheet is a harder drive than in steel, so the pilot hole should be revisited when the material changes rather than carried over.
Three assemblies where thread forming screws are the fixing:
| Where it sits | The screw closes a housing that must not contain loose material, where a cutting screw would leave chips inside the assembly. |
| When it goes wrong | Swarf from a cutting thread shorts a contact or jams a mechanism, and it cannot be cleaned out afterwards. |
| Why it happens | The housing is closed, the material is thin, and the screw is assembled once. |
| What we control | Thread and point checked, first article driven into the housing. |
| Where it sits | The screw forms a thread in a moulded boss, where material displaced into the flanks is stronger than a cut thread. |
| When it goes wrong | A hole that is too small splits the boss, and one that is too large leaves the screw turning. |
| Why it happens | The boss is moulded, the material yields, and the joint is assembled by hand. |
| What we control | Hole size agreed, first article driven into the boss and pulled. |
| Where it sits | The screw joins a thin panel where cutting a thread would thin the section and leave the joint weak. |
| When it goes wrong | A cutting screw removes the wall the thread needs, and the panel domes under a tight hole. |
| Why it happens | The sheet is thin, the joint needs the full wall, and the fixing is repeated. |
| What we control | Thread, hole and sheet thickness checked on the first article. |
Four reasons that matter on a screw that displaces rather than cuts, each tied to what the drawing has to prove:
|
Hole size and material agreed
The pilot hole is agreed with the screw and the material, because a forming thread sized for a cutting screw will split or dome the part it goes into. Basis: Hole, thread and material agreed. |
Head, thread and point in one route
The pan head and the cross recess are formed in one stroke, the forming thread is rolled and the point is formed to the drawing. Basis: One route from wire to finished screw. |
|
Driven into the real material
The first article is driven into the customer material and pulled, because the hole window only shows itself in the part it is meant for. Basis: First article driven into the material. |
First article fixes the setting
The first article fixes the wire, 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 thread forming screws from carbon steel wire on single-die headers that form the pan head and cut the cross recess in one stroke, roll the forming thread with a rounded crest, form the point to the drawing and plate the parts in black zinc. The first part of every run is measured on the head and thread, driven into a sample of the customer material and entered into a thread gauge before the batch continues.
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The crest profile is what separates a forming thread from a cutting one, and it is set by the thread rolls. A crest that is too sharp will cut instead of displacing, which defeats the purpose of the part; one that is too round will not enter the hole. The profile is checked on the first article and the rolls are changed on count, because wear shows up as a crest that has gone flat.
What decides whether thread forming screws pass is the thread profile, the head, the point and the plate. The inspection agreement covers those, and the criteria come from the drawing.
Thread profile on the projector |
Thread gauged per batch |
Hardness checked on the wire |
Salt-spray testing of the plate |
On thread forming screws the thread is checked for pitch, major diameter and crest profile on the projector, and the head for diameter, height and face flatness. The point is checked against the drawing, and the recess is driven with the production bit before the batch continues.
The acceptance that matters most on this part is a drive into the customer material. The first article is driven and pulled to the strip point, because a forming screw can pass every dimensional check and still split the boss it was made for.
Every shipment of thread forming 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 plating record is kept with the inspection file.
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 plating. The documents carry the drawing revision and the batch number, so a repeat order is made to the same thread form that was 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 forming screw the first article is driven into the customer’s own material, because the hole and the displaced thread are the joint. Buyers visit during the process to review samples and to see how the parts are formed.
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8,678+
customers served
|
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 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 |
A forming screw displaces material instead of cutting it. No swarf is produced and the wall is not thinned, but the hole has to be sized more accurately.
One that lets the material yield into the thread flanks. Sizing it for a cutting screw will split the boss or dome the sheet.
It is the usual choice in plastic: the compressed material around the thread is stronger than a cut thread and there is no slot to crack from.
Displacement takes more effort than cutting. A steady driver and a correctly sized hole keep the torque inside what the recess and the thread can take.
No. It is a thin indoor finish. For exposed joints use the stainless version of the same thread form.
Thread size and pitch, point form, head diameter and height, recess type, the material and thickness of the part, and the pilot hole.
How a thread forming screw project runs from drawing to repeat delivery:
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1
Send the drawing and the material it goes into
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→ |
2
Thread, point and pilot hole agreed
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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 thread size and pitch, the point form, the head diameter and height, the recess type, and the material and thickness of the part.
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Thread size
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Pitch
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Point form
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Head diameter
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Material
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Pilot hole
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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
