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:Countersunk Raised Head Screw, Dog Point, Self-Tapping (Non-Standard)
Materials:Carbon Steel
Surface treatment:Black Oxide
Head Type:Raised Countersunk Head (countersink cone with a short crowned boss above the panel face)
Drive:Pozidriv cross recess (four tapered wings plus four ribs at 45 degrees; no slot)
Thread:Coarse single-lead self-tapping thread, rolled, full to the head
Point:Blunt dog point below the minor diameter, flat end with a small chamfer; no taper, no drill point, no cutting slot
Forming:Single-die heading, thread rolling, black oxide, sorting
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:401
We manufacture countersunk raised head screws: a countersink cone with a short crown above it, Pozidriv drive, dog point and a coarse self-tapping thread, in carbon steel with a black oxide finish. Cone angle, crown height, dog point and length are taken from your drawing.
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.
Countersunk raised head screws are screws with a countersink cone under the head and a short crowned boss above it, so the cone seats in a machined recess while a small dome stands proud of the panel face. The recorded item on this page is a carbon steel self-tapping version with a Pozidriv drive, a blunt dog point and a black oxide finish, quoted from M1 to M14 with Number 401.
The two-part head. Below the panel line is a cone that matches the countersink; above it is a shallow crown. The cone centres the screw and takes the load, and the crown is what is seen and what gives the drive its depth.
Pozidriv drive. A cross with four additional ribs set at 45 degrees between the wings. The ribs let the bit seat deeper and turn harder before it cams out, which is the reason Pozidriv exists alongside Phillips.
Dog point. The end is blunt and turned below the minor diameter, with a flat face and a small chamfer. There is no taper, no drill point and no cutting slot: the dog point finds a pilot hole and guides the screw straight rather than cutting its own way in.
Self-tapping thread. A coarse single-lead thread rolled full to the head. It forms its own thread in a prepared hole, in plastics, soft metals or thin sheet with a pilot, and it is not a machine screw.
Black oxide. A thin conversion coating that darkens the surface rather than building on it. On countersunk raised head screws it keeps the head looking black in a dark assembly without adding enough thickness to change the seat.
Together these decide the joint: the cone seats in the countersink, the crown covers the recess, the Pozidriv bit turns it without slipping, the dog point lines it up, and the self-tapping thread holds it.
The body is carbon steel wire, with grade and heat number on the batch record. The head is upset in one stroke that forms the cone and the crown together, because the two are one continuous surface from the rim of the countersink up over the dome. If they are formed separately, the transition shows as a ring.
The cone angle is the dimension that decides whether the head seats. It has to match the countersink in the panel; a head cut at one angle in a recess cut at another touches on a line rather than on a face, and the joint loosens as the line wears. The angle and the seat diameter are checked on the first article against the recess, not only against the drawing.
The crown is short by design. It carries the recess and adds enough material for the Pozidriv depth, but it is not meant to be a dome to be gripped or a boss to be pressed. Its height above the panel is a visible dimension, because a crown that is too tall stands out on a flat face and one that is too low leaves the recess shallow. On countersunk raised head screws the crown height is therefore quoted as a tolerance, not as a nominal.
The dog point is turned below the minor diameter. That step is what lets the point enter a pilot hole without starting a thread in it, and it gives the screw a lead-in that keeps it square while the first thread engages. A dog point that is too long wastes usable thread; too short and the screw starts at an angle.
The thread is rolled after the head is formed and runs to the underside of the cone. Black oxide follows, and because the coating is a conversion layer rather than a deposit, the thread and the point keep their dimensions and are gauged before and after the treatment.
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 countersunk raised head screws the countersink is part of the length decision, because the cone sits below the panel face and the crown above it. Lengths for countersunk raised head screws are quoted from the top of the crown for that reason.
| Item | How it is defined | What we control |
|---|---|---|
| Thread | Coarse single-lead self-tapping thread | Gauged per batch |
| Cone angle | Matches the countersink in the panel | Checked against the recess on the first article |
| Head diameter | Across the crown, set on the drawing | Measured on the projector |
| Crown height | Above the panel face | Measured from the cone rim |
| Recess | Pozidriv cross with four ribs | Driven with a PZ bit on the first article |
| Dog point | Below the minor diameter, flat end | Diameter and length checked on the first article |
| Length | From the top of the crown to the tip | Measured on the shop plate |
Length on a raised head is measured from the top of the crown rather than from the cone rim, and the two differ by the crown height. A drawing that quotes length from the seat will produce a screw that sits one crown-height deeper than expected. The same applies to the usable thread: the thread starts at the cone, so the engaged length is the quoted length minus the crown and the cone.
The countersink in the panel and the head have to be a matched pair. When a drawing is transferred from one assembly to another, the recess angle is the first thing to check, because a 90-degree recess with an 82-degree head looks correct from above and is wrong at the contact face.
Three features do the work on this part, and each of them is a trade against something. Knowing which trade applies is what keeps a specification honest.
| Feature | What it gives | What it costs |
|---|---|---|
| Raised countersunk head | Domed face with a flush cone, recess for the drive | Stands above a flat panel; needs a matching crown height |
| Pozidriv recess | More torque before cam-out than Phillips | Needs a PZ bit; a PH bit will not seat properly |
| Dog point | Straight start in a pilot hole | No thread on the point; not for blind holes |
| Self-tapping thread | Forms its own thread in a prepared hole | Not for a tapped machine thread |
| Black oxide | Dark finish, almost no dimensional change | Thin protection; not for wet or coastal service |
The raised head exists because a flat countersunk head leaves nothing above the surface to hold a recess deep enough for a Pozidriv, and because a domed head is what some fittings are designed around. A hinge leaf, a latch or a marine fitting often has a countersunk recess with a raised head in mind, and a flat head in that recess reads as a mistake even when it fits.
The Pozidriv bit is not interchangeable with Phillips. A PZ bit in a Phillips recess will not bottom, and a PH bit in a Pozidriv recess will sit high and cam out early. On countersunk raised head screws the recess also has to be deep enough after the crown height is set, so the recess depth and the crown height are reviewed as a pair.
The dog point is the feature that decides where the part can be used. It starts in a pilot hole and keeps the screw square while the thread bites, which matters in plastic bosses and in thin sheet where an angled start tears the hole. It is not a cutting point, so it will not make its own hole in solid material, and it should not be used where the hole is blind and short.
Black oxide is a conversion coating: the surface is chemically darkened rather than covered with a layer. That is why it suits countersunk raised head screws, because a cone that has to seat in a recess cannot tolerate a thick deposit on its face. That is the practical reason countersunk raised head screws are so often supplied in black oxide.
| Finish | How it protects | Effect on the cone and thread | Typical use |
|---|---|---|---|
| Black oxide | Thin conversion layer, lightly oiled | Almost no dimensional change | Dark assemblies, indoor hardware |
| White zinc | Sacrificial zinc, blue-white passivation | A few microns; gauged after | Indoor general assembly |
| Yellow zinc | Sacrificial zinc, yellow passivation | A few microns; gauged after | Warm-tone indoor parts |
| Dacromet | Zinc-aluminium flake layer, cured | Thin film; thread re-checked | Outdoor and wet assemblies |
| Stainless (equivalent part) | Alloy provides protection | No coating | Wash-down and coastal work |
Black oxide on its own is not a corrosion barrier. It is usually supplied lightly oiled, and in a dry indoor assembly that is enough; in a wet or coastal one it is not, and the same screw in a Dacromet or stainless version is the right answer. The drawing should say which environment the part is going into rather than only the finish name.
Because the coating is thin, the thread is gauged after treatment with little correction. That is the practical advantage on a self-tapping screw: the forming thread is the part that does the work, and a finish that adds thickness to it changes how much torque the joint takes to close.
Three assemblies where a domed head over a countersunk seat is the point of the design:
| Where it sits | The screw seats in the countersunk recess of a hinge leaf or a latch plate and the crown finishes the visible face. |
| When it goes wrong | A flat head leaves a hole that reads as unfinished, and a cone that does not match the recess rocks the leaf and the door drops. |
| Why it happens | The fitting has a machined countersink, the face is visible, and the screw is adjusted in service. |
| What we control | Cone angle matched to the recess, crown height checked, and the first article fitted in the actual hardware. |
| Where it sits | The screw closes a cover or fixes a panel on equipment with a black finish, where the head has to disappear into the case. |
| When it goes wrong | A bright plated screw stands out against black, and a thick coating on the cone stops it seating flush. |
| Why it happens | The assembly is dark, the recess is milled into the case, and the screws are in a row. |
| What we control | Black oxide confirmed for tone and thickness, recess driven with a PZ bit. |
| Where it sits | The screw forms its own thread in a prepared hole in a soft material, with the dog point keeping it square as the thread starts. |
| When it goes wrong | A pointed screw starts its own path and can wander, and a thread that starts at an angle tears the boss. |
| Why it happens | The material is soft, the hole is drilled to size, and the joint is made once on a line. |
| What we control | Dog point diameter and length checked, and the first article driven into a sample of the same material. |
Four reasons that matter on a raised head self-tapping screw, each tied to what the drawing has to prove:
|
Cone and crown reviewed as one head
The cone angle, the crown height and the recess depth are reviewed together against the countersink, so a head that will not seat is raised before the die is cut. Basis: Cone, crown and recess reviewed against the countersink. |
Head, point and thread in one route
The raised head is upset in one stroke, the dog point is turned on centre and the thread is rolled to the cone, so the point and the head stay concentric. Basis: One route from wire to finished screw. |
|
Cone seat and dog point checked on the part
The cone is checked against a recess sample, the dog point is measured below the minor diameter, and the recess is driven with a PZ bit. Basis: First article fitted in the real recess. |
First article to repeat production
Everything that decides the batch – drawing revision, wire heat, die set, thread roll – is fixed at the first article and reused for repeats. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these countersunk raised head screws on a single-die header that upsets the countersink cone and the crown in one stroke, turns the dog point on centre and rolls the coarse thread up to the cone. The parts are black oxide finished. The first part of every run is measured on the cone angle, the crown height and the dog point, and driven into a recess sample, before the batch continues.
|
|
The cone is the feature that needs the most care in the die. It has to be cut as a true surface from the rim to the crown, with no step where the two meet, because a step is a line that will not seat. On a self-tapping screw the thread roll is set to end at the underside of the cone, and the dog point is turned in a separate station so that its diameter is independent of the thread.
What decides whether countersunk raised head screws pass is the cone, the crown, the recess, the dog point, the thread and the finish. The inspection agreement covers those, and the criteria come from the drawing.
Head profile on the projector |
Thread gauged per batch |
Hardness testing against the property class |
Salt-spray testing where a coating is specified |
The cone is checked with a recess sample as well as on the projector. A cone can measure correctly in profile and still not seat if its surface is not continuous, and the sample test is what shows the difference: a correctly seated head leaves an even contact ring, and one that touches on a line shows only at the edges.
The dog point is checked below the minor diameter with a micrometer, and its length is measured from the end of the thread. A dog point that has picked up thread in the roll will start a thread in the pilot hole and the joint will bind before the cone seats, which is the failure this dimension is there to prevent. Every batch of countersunk raised head screws is checked on the point for that reason, not only on the thread.
Every shipment of countersunk raised head 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, 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 finish. 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 raised head the first article is fitted into the customer’s own countersink, because that is the only place the cone angle and the crown height can be judged together. Buyers visit during the process to review samples and to see how the heads are formed.
|
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 header and the finishing 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 countersink cone under the head and a short crown above it. The cone seats in a machined recess and the crown stands slightly proud, so the visible face is domed rather than flush.
A flat countersunk head finishes flush with the panel and has no room above the surface for a deep recess. The raised head keeps a domed face and gives the drive more depth.
No. Pozidriv has four additional ribs between the wings, which lets the bit seat deeper and turn harder before it cams out. The bits are not interchangeable.
It is a blunt end turned below the minor diameter. It enters the pilot hole and keeps the screw square while the thread starts, without cutting or forming thread in the hole itself.
Black oxide, which is a thin conversion coating. It gives a dark finish with almost no dimensional change and is intended for dry indoor assemblies.
Thread size and pitch, cone angle, head diameter, crown height, recess size, dog point diameter and length, length and its datum, material and the finish.
How a countersunk raised head screw project runs from drawing to repeat delivery:
|
1
Send the drawing or sample
|
→ |
2
Cone and crown review
|
→ |
3
First article fitted in the recess
|
→ |
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 thread size and pitch, cone angle, head diameter, crown height, recess size, dog point diameter and length, length and datum, material and finish.
|
Thread and pitch
|
Cone angle
|
Head diameter
|
|
Crown height
|
Dog point
|
Length and datum
|
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
