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:phillips countersunk screw
Materials:Steel
Surface treatment:White Zinc Plated
Head Type:Flat Head
Drive:Phillips
Thread:Self Tapping
Point:Flat Point
Forming:Single Die Heading
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:207
We make phillips countersunk screws in white zinc plated carbon steel with a self tapping thread and a flat point, quoting them from M1 to M14. Cone angle, thread, point and plating come from your drawing, and the first article is seated in your own panel before the batch runs.
Watch the factory video·Email sst@szsst88.com
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 countersunk screw seats flush on a cone and is driven through a cross recess, and in the form on this page it carries a self tapping thread that forms its own thread in the panel. The recorded item is white zinc plated carbon steel with a countersunk head and a flat point, quoted from M1 to M14 with Number 207.
Countersunk head. A cone that seats in a matching countersink and leaves the surface unbroken. The cone centres the screw as it is turned and carries the clamp load over its whole area.
Cross recess. Four tapered wings around a pointed centre. The bit centres itself and cams out before the head is destroyed, which on a flush head is the only warning there is.
Self tapping thread. A coarse thread with a sharp crest that forms its own thread in the hole, ending in a flat point for a drilled or punched hole.
White zinc. Electroplated zinc with a blue-white passivation, thin enough that the thread still forms its way in and bright enough for a visible panel.
On phillips countersunk screws the panel is asked to do two things at once. The countersink removes material in a cone at the surface, and the thread forms in the material that is left. Both come out of the same sheet thickness, so the two features compete for it, and that competition is what decides whether the joint works.
On phillips countersunk screws the countersink depth is the first constraint. A cone cut too deep into thin sheet leaves a knife edge at the rim of the hole, and that edge cracks when the thread expands the sheet; a cone cut shallow leaves the head standing proud, which defeats the purpose. The depth is a fraction of the thickness, and the fraction is agreed with the panel rather than with the screw.
The thread engagement is the second. A self tapping screw needs a certain number of turns in the material to reach its strip torque, and the countersink has already taken some of the thickness away. On a thin gauge the engagement left after the countersink is small, and the joint strips before the head seats.
That is why a phillips countersunk screw is normally quoted for panels above a threshold thickness, and why a pan head or a raised head is the answer below it. The head form is a decision about the material, not a preference about appearance.
White zinc goes on after the thread is rolled. It is a few microns and it follows the thread, so the crest is coated; the countersunk cone is the largest visible surface, and on a flush fixing that cone is what the customer judges.
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 phillips countersunk screws the cone angle, the point and the thread length are quoted with the length, because all of them are read against the panel.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Countersunk cone, flush top | Cone angle, diameter and concentricity |
| Recess | Phillips cross | Depth and width, bit tried after plating |
| Thread | Coarse self-tapping, full length | Gauged per batch after plating |
| Point | Short taper, flat tip | Checked on the first article |
| Plating | White zinc, blue-white passivation | Thickness range and salt-spray sample |
| Length | From the top of the head to the point | Measured on the shop plate |
Length is quoted from the top of the head, because a countersunk head finishes flush and the top face is the datum that shows. Measuring from the start of the cone gives a screw that is short by the head depth, and in a thin panel that is the whole engagement on the far side.
The cone angle is a joint dimension as much as a screw dimension. The countersink in the panel has to be cut at the same angle, and on thin sheet the countersink is often formed rather than cut, which leaves it a degree or two off. The first article is seated in a sample panel rather than judged against the drawing.
Three features define phillips countersunk screws: the countersunk head, the self tapping thread and the white zinc finish. The first two have to be matched to the panel; the third is what keeps the cone presentable.
| Combination | What it gives | Where it fits | Where it fails |
|---|---|---|---|
| Countersunk, self tapping | Flush joint with no nut | Sheet above a thickness threshold | Thin sheet: the cone cracks or strips |
| Pan, self tapping | Load spread, no countersink | Thin sheet and thin sections | Anywhere the head may not stand proud |
| Countersunk, machine | Flush and removable | Tapped or nutted joints | No thread to form in the panel |
| Raised countersunk, tapping | Flush seat plus a visible dome | Soft panels where a flush rim shows |
The advantage over a machine screw is that the panel needs no tapping. On a small sheet-metal assembly that is one operation removed, one tool removed and one failure mode removed — a broken tap in a thin panel ends the part, while a stripped tapping screw can at least be replaced with a larger one.
The cost is the margin in the sheet. A flush tapping screw has less material to work with than any other combination on the same panel: the countersink takes some, the thread needs the rest. That is why the form is chosen for panels where the gauge is known and stable, and avoided where the gauge varies from batch to batch.
Phillips countersunk screws carry a white zinc finish with a blue-white passivation, applied after the thread is rolled. It is a sacrificial coating: a scratch at the cone still has zinc at its edges, and the cone is the surface that gets scratched, because it is the surface that rubs as the head seats.
| Finish | How it protects | Effect on cone and recess | Typical use |
|---|---|---|---|
| White zinc | Sacrificial zinc, blue-white passivation | A few microns; both re-checked | General indoor panels |
| Black zinc | Zinc with dark passivation | A few microns; both re-checked | Dark visible panels |
| Nickel plate | Hard barrier deposit | Thicker; cone and recess re-checked | Bright visible fixings |
| Dacromet | Zinc-aluminium flake layer | Film builds; thread re-checked | Outdoor and damp panels |
| Stainless, plain | Passive chromium oxide film | None; gauged as formed | Washed and coastal joints |
On a countersunk head the cone is the largest coated surface, and it is also where the coating wears first: seating the head rubs it against the countersink, and a plated cone shows a bright ring after the joint has been tightened and opened once. On white zinc that ring is visible in a way it would not be on a painted head.
The plating also changes the thread that forms the panel thread. A few microns on the crest changes the driving torque against a hole of fixed size, so the pilot hole is agreed on plated parts. On a flush fixing there is leftover thickness after the countersink, and an increase in driving torque is the thing that starts the cone cracking.
Three assemblies where a phillips countersunk screw is the fixing:
| Where it sits | The screw closes a panel or fixes a plate where the surface has to be flat and the hole is punched, with enough gauge for a countersink. |
| When it goes wrong | A countersink in thin sheet leaves a knife edge that cracks when the thread expands, and the head then sits in a split hole. |
| Why it happens | The gauge is adequate, the surface is flush, and the fixing repeats. |
| What we control | Cone angle and thread checked, pilot hole agreed on the customer’s sheet. |
| Where it sits | The screw fixes a visible face plate where a proud head would catch and collect dirt, and the panel is painted or coated. |
| When it goes wrong | A head that stands proud shows on a flat face, and a cone that is out of angle rocks on the paint. |
| Why it happens | The face is visible, flush matters, and the joint is serviced. |
| What we control | Cone seated in a sample panel, recess driven with the production bit. |
| Where it sits | The screw joins a hinge, a plate or a fitting into a self-tapping hole where the fixing is seen and the gauge is known. |
| When it goes wrong | A stripped thread in thin sheet cannot be repaired, and a proud head marks whatever is stacked against it. |
| Why it happens | The fixing is visible, the gauge is stable, and the assembly is made once. |
| What we control | Point and thread tested on the customer material, plating thickness held. |
Four reasons that matter on phillips countersunk screws, each tied to what the drawing has to prove:
|
Cone, thread and gauge reviewed together
The cone angle, the thread and the panel gauge are reviewed as one set, so a countersink that would knife-edge or a thread that would strip is raised before the die is cut. Basis: Cone, thread and gauge reviewed as one set. |
Heading, rolling and plating in one route
The countersunk head and the cross are formed in one stroke, the thread is rolled to a flat point and the parts are white zinc plated in the same route. Basis: One route from wire to plated screw. |
|
Cone seated, thread driven
The cone is checked for angle and the first article is seated in the customer panel; the thread is gauged after plating and driven into the sheet. Basis: First article seated in the customer panel. |
First article fixes the setting
The first article fixes the wire heat, die set, roll and plating barrel; repeat orders are compared against that record. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these phillips countersunk screws from carbon steel wire on single-die headers that cut the countersunk cone and the cross recess in one stroke, rolls the coarse thread to a flat point and white zinc plates the parts. The first part of every run is measured on the cone, driven with the production bit and driven into a sample of the customer’s sheet before the batch continues.
|
|
The cone is cut by the die, and a die that is worn at the cone leaves a head that is slightly barrel-shaped: the top looks right, the angle is half a degree out, and the head seats on a line. On a flush joint that shows as a crescent of light and a joint that rocks, which is why the cone is gauged rather than eyeballed.
What decides whether phillips countersunk screws pass is the cone, the recess, the thread and the plating. The inspection agreement covers those, and the criteria come from the drawing.
Cone angle and diameter on the projector |
Thread gauged after plating |
Hardness testing against the property class |
Salt-spray testing of the white zinc plate |
The cone is checked for angle, diameter and concentricity and then seated in a sample of the panel. Seating is the customer’s acceptance test on a flush joint, and it catches the ring of contact that no dimension describes.
The thread on phillips countersunk screws is gauged after plating and driven into the customer’s sheet, with driving and strip torque recorded together. On a flush tapping screw the countersink has already removed some of the material the thread needs, so the strip torque is lower than the gauge alone would suggest.
The recess is driven with the production bit, and the plating is measured on the batch sample rather than judged by its brightness.
Every shipment of phillips countersunk 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 phillips countersunk screws the first article is also seated in the customer’s own panel, so the cone and the countersink are proved together. Buyers visit during the process to review samples and to see how the heads are formed and the parts plated.
|
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 |
Only if the gauge is enough for the countersink and the thread. In very thin sheet the cone leaves a knife edge that cracks, and a pan or raised head is the right answer.
The same angle as the cone, normally ninety degrees. On thin sheet the countersink is often formed rather than cut, so the angle is checked on a sample panel rather than assumed.
Yes. The thread has to form against a hole of a defined size, and the hole is agreed on a sample of the actual sheet.
Because the countersink has already removed some of the material the thread engages. On a thin gauge the engagement left is small.
From the top of the head, since the head finishes flush. From the start of the cone would give a screw short by the head depth.
Cone angle and diameter, recess size, thread size and point type, length from the top of the head, the panel gauge, and the plating.
How a phillips countersunk screw project runs from drawing to repeat delivery:
|
1
Send the drawing or the sheet sample
|
→ |
2
Cone, thread and gauge review
|
→ |
3
First article seated in your panel
|
→ |
4
Batch production and repeat orders
|
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 cone angle and diameter, the recess size, the thread size and point type, the length from the top of the head, the panel gauge and the plating.
|
Cone angle
|
Head diameter
|
Recess size
|
|
Thread and point
|
Length
|
Panel gauge and plating
|
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
