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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:Countersunk (flat head) Phillips self-tapping screw, single-lead coarse thread, sharp gimlet point (Non-Standard)
Materials:Carbon Steel
Surface treatment:Nickel Plated (bright) or Black Zinc Plated, per drawing
Head Type:Countersunk flat head: 90-degree cone, wide flat top with a slight dome and a small crown at the rim, no flange
Drive:Phillips cross recess, four tapered wings with a pointed centre; no slot, no hexagon socket
Thread:Coarse single-lead self-tapping thread, full length from the head cone to the point, no plain shank
Point:Sharp tapered gimlet point; no drill point, no cutting slot, no notch
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Forming:Single-die cold heading, thread rolling, plating, sorting
Number:80
We manufacture self tapping flat head metal screws with a 90-degree countersunk head, a Phillips recess, a coarse self-tapping thread and a sharp gimlet point, in carbon steel with nickel or black zinc. Cone angle, head diameter, point, length and finish 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.
Self tapping flat head metal screws are self-tapping screws with a countersunk head that finishes flush with the surface they go into. The recorded item on this page is a carbon steel screw with a 90-degree flat head, a Phillips recess, a coarse single-lead self-tapping thread running the full length, and a sharp tapered gimlet point, quoted from M1 to M14 with Number 80.
Flat head, 90 degrees. The head is a cone with a wide flat top and a small crown at the rim. It seats in a countersink and leaves the surface flush, which is the whole point: nothing stands above the panel to catch, snag or show.
Phillips recess. A cross with four tapered wings and a pointed centre. It centres itself in the countersink, which on a flush fixing matters because a bit that wanders crushes the edge of the countersink before the head has even started into it.
Coarse self-tapping thread. A single-lead thread rolled over the full length from the head cone to the point, with no plain shank. The thread does the holding, and the coarse pitch gives it grip in the materials these screws are used for.
Sharp gimlet point. A tapered point that starts in a prepared hole and leads the thread in. It is not a drill point: self tapping flat head metal screws of this type expect a pilot hole, and the point’s job is to enter it squarely rather than to make it.
Nickel or black zinc. Two finishes are recorded. Bright nickel for a visible flush fixing that should read as a clean silver dot; black zinc where a dark head has to disappear into a dark panel.
The head is upset in a single heading stroke with the cone, the flat top and the small crown formed together, and the Phillips recess is formed in the same stroke. Forming the recess with the head keeps it concentric with the shank, which is what makes the bit sit square in a counterbored hole.
The 90-degree cone is the dimension that decides whether the head seats. It has to match the countersink in the panel, and the seat has to be continuous: a cone with a step or a burr touches on a line, and on a flush fixing that line is a ring of crushed material around a head that stands slightly proud.
The thread is rolled from the cone to the point. Running it all the way to the cone means the whole length below the surface is working length, which is why the length of these screws is quoted differently from a pan head part — the head is buried, so the screw that fills the hole is the whole screw minus the cone depth.
The gimlet point is formed after rolling. It is a sharp taper with a slight lead-in rather than a drill point with cutting lips, and that difference decides the material: a gimlet point suits timber, board and plastics, and in sheet metal it needs a drilled hole to start in.
Nickel or black zinc is applied after the thread is rolled. Either finish adds a few microns to the cone and to the recess, so the head is checked against a countersink sample in its plated condition and the recess is driven with the production bit after plating.
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; self tapping flat head metal screws are normally short, because the thread is holding through a panel or a board rather than clamping a deep stack.
| Item | How it is defined | What we control |
|---|---|---|
| Head angle | 90 degrees, to match the countersink | Checked on the projector |
| Head diameter | Set by the JIS form recorded for this part | Measured on the first article |
| Head depth | Cone depth below the surface | Checked on the section |
| Recess | Phillips cross | Driven with the production bit |
| Thread | Coarse single-lead self-tapping, full length | Gauged per batch |
| Point | Sharp tapered gimlet | Checked on the first article |
| Length | Overall, top of head to point | Measured on the shop plate |
Length on a countersunk screw is measured overall, from the top of the head to the point, because the head sits below the surface. The working length is that figure minus the countersink depth, and the two are quoted together on any joint where the thickness is tight. A drawing that gives only the overall length leaves the countersink depth to be guessed, and on a thin panel the guess is the difference between closing and not.
The head diameter and the cone angle are set by the standard the drawing cites, which for the recorded part is the JIS form. A JIS countersunk head and an ISO countersunk head are close but not identical at every size, and a head from the wrong series sits on the countersink in the wrong place — so the standard belongs on the drawing next to the head dimensions.
A flush head changes what the fixing can do, and the trade is worth stating before a specification is fixed.
| Feature | What it gives | What it costs |
|---|---|---|
| Countersunk head | Flush finish, nothing to catch | Head sits below the surface; the cone must match |
| Self-tapping thread | Holds without a nut | Needs the right pilot hole |
| Gimlet point | Clean start in wood, board and plastics | Not for sheet metal without a drilled hole |
| Compact head height | Fits thin panels and tight recesses | Less bearing area than a pan head |
| Plated finish | Bright or black as specified | Plating adds to the cone and the recess |
The flush head is the reason these screws are used on visible faces and on surfaces that slide or are handled. A pan head on a shelf, a bunk, a cover or a panel edge catches on whatever passes over it; a countersunk head does not. The price is that the joint now depends on the countersink as much as on the screw, and a countersink that is drilled too deep lets the head sink below the surface and split the panel.
The gimlet point is the feature that decides the material. In timber and board it starts and leads the thread with no drama; in sheet metal it will skate unless a hole has been drilled first. Where the joint is metal, the same head is available with a drill point, and that is a different part rather than a variation of this one.
The bearing area is smaller than a pan head of the same thread, and that is the honest limit. On a soft board or a thin skin, a countersunk head concentrates load on the cone; where the panel is soft, a washer head or a plain pan head spreads it better. Self tapping flat head metal screws are the right answer where the face has to be flat, not where the material is weak.
Two finishes are recorded for this part: bright nickel and black zinc. Both are thin decorative finishes over carbon steel, and the choice is about what the head has to look like rather than about how the screw holds.
| Finish | How it protects | Effect on cone and recess | Typical use |
|---|---|---|---|
| Bright nickel | Hard metallic deposit, decorative | A few microns; checked in the countersink sample | Visible flush fixings |
| Black zinc | Zinc layer with black passivation | A few microns; gauged after | Dark panels and black hardware |
| White zinc | Sacrificial zinc, blue-white passivation | Thin; cone unchanged in practice | General indoor work |
| Yellow zinc | Sacrificial zinc, yellow passivation | A few microns; gauged after | Warm-tone indoor hardware |
| Dacromet | Zinc-aluminium flake layer, cured | Thin film; cone re-checked | Outdoor and wet assemblies |
The cone is where plating matters most on this part. A deposit on the cone changes the angle very slightly, and on a flush head that is enough to make the seating ring move from the middle of the cone to its edge. That is why the head is checked in a countersink sample after plating rather than measured on a bare part.
Of the two recorded finishes, black zinc gives more protection because the zinc is sacrificial; nickel is harder and brighter but relies on the deposit staying intact. Where the joint is outdoors, neither is the right answer, and a Dacromet or stainless version of the same head is what the application actually needs.
Three assemblies where the head has to finish flush:
| Where it sits | The screw fixes a bracket, a rail or a panel where the head sits in a countersink and the surface is handled or slid over. |
| When it goes wrong | A raised head catches and marks, and a countersink that is too deep or too shallow leaves the head proud or sunk. |
| Why it happens | The face is visible and flat, the material is board or timber, and the joint is made on a line. |
| What we control | Cone angle against the countersink, point checked on a sample of the board, plated condition confirmed. |
| Where it sits | The screw closes a cover or fixes a trim on a painted or coated steel skin, where the head has to disappear into the face. |
| When it goes wrong | A proud head reads as unfinished, and a cone that crushes the paint leaves a ring around the fixing. |
| Why it happens | The panel is thin and coated, the face is seen, and the joint is opened occasionally. |
| What we control | Cone and plated condition checked, and the first article seated in a painted sample panel. |
| Where it sits | The screw assembles a frame, a shelf or a graphic panel where the fixing is on a visible face and has to be flush. |
| When it goes wrong | A pan head stands above the surface and catches on cloth or fingers, and a bright head on a dark display breaks the line. |
| Why it happens | The structure is reused, the faces are visible, and the fixings are in rows. |
| What we control | Head diameter and finish matched, cone checked in a countersink sample. |
Four reasons that matter on a flush fixing, each tied to what the drawing has to prove:
|
Cone and standard reviewed together
The cone angle, the head diameter and the standard cited are reviewed as one set against the countersink, so a head that will not seat is raised before tooling. Basis: Cone and standard reviewed as one set. |
Head, recess and thread in one route
The cone and the recess are formed in one stroke, the thread is rolled to the point, and the finish is applied after rolling. Basis: One route from wire to plated screw. |
|
Seat and recess checked on the part
The cone is checked in a countersink sample and the recess is driven with the production bit, both after plating. Basis: First article seated in a countersink sample. |
First article to repeat production
The first article fixes the drawing revision, wire heat, die set, thread roll and finish; repeat orders are compared against that record. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these self tapping flat head metal screws on a single-die header that upsets the 90-degree cone and the Phillips recess in one stroke, rolls the coarse thread from the cone to a sharp gimlet point, and plates the parts in nickel or black zinc as the drawing specifies. The first part of every run is seated in a countersink sample and driven into a sample of the material, before the batch continues.
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The cone is the operation that decides the part. It has to run from the crown to the recess as one continuous surface, and the point where the cone meets the shank has to be a clean circle rather than a step. On a flush fixing every one of those details is visible at the surface, which is why the seat is checked in a countersink sample and not only on the projector.
What decides whether self tapping flat head metal screws pass is the cone, the head, the recess, the thread, the point and the finish. The inspection agreement covers those, and the criteria come from the drawing.
Cone angle on the projector |
Thread gauged per batch |
Hardness testing against the property class |
Salt-spray testing of the plated part |
The seat is checked by driving the first article into a countersink sample and looking at the contact ring. A cone that measures correctly can still seat on a line if its surface is not continuous, and on a flush head that shows as a head standing half a tenth proud with a bright ring around it.
The recess is checked after plating, with the production bit at the joint torque. Plating narrows the recess and rounds the cone at the same time, so the two checks are done together on the same part rather than separately on different samples.
Every shipment of self tapping flat head metal 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, together with the plating record, 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 a flush fixing the first article is seated in the customer’s countersink, because the seat is decided by the panel and not by the screw alone. 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
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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 header 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 self-tapping screw with a countersunk head that seats in a countersink and finishes flush. This page’s part is a 90-degree head with a Phillips recess and a gimlet point.
Overall, from the top of the head to the point. The working length is that minus the countersink depth, so both figures belong on the drawing.
A sharp gimlet point starts in timber, board and plastics. In sheet metal it needs a drilled hole, or the same head with a drill point, which is a different part.
It can. The countersink has to be cut cleanly and to the right depth, and the head checked in a countersink sample after plating, or the cone will bear on a ring and mark the paint.
Bright nickel for a visible clean head, black zinc for a dark panel. For outdoor joints neither is enough, and a Dacromet or stainless version is the right choice.
Thread size and pitch, head diameter, countersink angle, the standard cited, recess, point form, overall length and finish.
How a self tapping flat head metal screw project runs from drawing to repeat delivery:
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1
Send the drawing or a countersink sample
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→ |
2
Cone and standard review
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→ |
3
First article seated and driven
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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, head diameter, countersink angle, the standard cited, recess, point form, overall length, material and finish.
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Thread and pitch
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Head diameter
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Countersink angle
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Standard cited
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Point form
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Overall length
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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
