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+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:Tapered Socket Head Cap Screw
Materials:Carbon Steel
Surface treatment:Zinc Plated
Head Type:Taper Washer Head
Drive:Hexagon socket, Allen key driven; no cross recess
Thread:Metric machine thread, rolled 60 degrees, full to the collar
Point:Blunt end with a small chamfer; no taper, no drill point
Forming:Single-die heading with taper and socket punch, thread rolling, colour zinc plating, sorting
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:256-1
We manufacture tapered socket head cap screws with a conical bearing face under an integral collar and a hexagon socket drive, in carbon steel with a colour zinc finish. Taper angle, collar diameter, socket depth and length 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 tapered socket head cap screw is a machine screw driven with an internal hexagon, whose head carries a conical bearing face under an integral collar. The recorded item on this page is carbon steel with a colour zinc finish, a metric machine thread and a hexagon socket, quoted from M1 to M14 with Number 256-1.
Tapered head. The underside of the head is a shallow cone rather than a flat ring. The cone centres the screw in a matching countersink, so the head locates itself as it seats instead of relying on the clearance hole.
Integral collar. Above the taper there is a collar, formed with the head, which gives the bearing face its width. The collar is what the head actually sits on once the taper has centred it, and it is why this head spreads load better than a plain taper.
Hexagon socket. Six flats sunk in the top face, driven with an Allen key. The socket takes more torque than a cross of the same head size and it needs no clearance around the head, which is what makes it usable in a recess.
Machine thread. A rolled thread for a tapped hole or a nut, with a blunt end. The screw does not cut its own thread: the hole is already there.
Colour zinc. A zinc plate with an iridescent passivation, which reads as a yellow-green sheen rather than a plain silver. It is the standard bright protection for indoor steel fasteners and it is thin enough to leave the taper and the socket as formed.
The head, the collar and the taper are formed in one heading stroke, and the socket is punched into the top face in the same operation. Doing all of it at once is what keeps the taper concentric with the socket: if the socket is punched after the head is finished and runs slightly off, the key tips the screw and the taper bears on one side.
The taper angle has to match whatever it seats into. In a matching countersink the head centres and seals; in a plain hole it does nothing, and the collar is left carrying the load on its own. That is why the angle is a quoted dimension rather than a die detail.
The collar is the bearing face and it is deliberately wider than the taper. Once the taper has centred the screw, the collar sits flat and spreads the clamp load, which on a thin panel is what keeps the head from dishing the sheet around the hole.
The thread is rolled from under the collar to the blunt end. There is no plain shank, so the whole length below the head engages; the chamfer at the end lets the first thread enter without catching.
Colour zinc is applied after rolling. It is thin, so the thread and the socket are gauged in the plated condition without correction, and the taper keeps its angle because there is no heavy deposit on it.
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 a tapered socket head cap screw the length is measured under the collar, and the taper depth is part of the stack rather than part of the screw length.
| Item | How it is defined | What we control |
|---|---|---|
| Thread | Metric machine thread, rolled, full length | Gauged per batch after plating |
| Socket | Hexagon, sized to the thread | Checked with the key on the first article |
| Taper angle | Under the collar, matching the seat | Checked on the projector and in a sample seat |
| Collar diameter | The flat bearing face | Measured on the first article |
| Head height | Socket depth plus collar thickness | Checked on the section |
| Length | From under the collar to the end | Measured on the shop plate |
The taper angle is the dimension that decides whether the head works. A taper that matches the seat centres the head and makes the joint self-locating; one that is a couple of degrees off bears on a line, and the collar never touches the surface it is meant to clamp.
The socket size is the second. A key one size small will enter and round the hexagon under load, and on a cap head the corners are where that starts — the first sign is a polished line inside one flat rather than a stripped socket.
The combination of a tapered seat and a hexagon socket answers two problems at once: where the screw sits, and how hard it can be turned.
| Feature | What it gives | What it costs |
|---|---|---|
| Tapered seat | Self-centring in a matching countersink | Taper angle must match the seat |
| Integral collar | Wide flat bearing face once centred | Head is taller than a plain taper |
| Hexagon socket | Torque without clearance around the head | Needs an Allen key |
| Full machine thread | Engagement over the whole length | No plain shank to locate the screw |
| Colour zinc | Thin bright protection with an iridescent tone | Indoor finish; gives way outdoors |
The self-centring is the reason to choose a taper over a flat head. On a joint where the clearance hole is a little generous, a flat head can sit off centre and the collar bears unevenly; a taper finds the seat and pulls the screw straight as it tightens. That matters on a row of fixings where an off-centre head is obvious.
The socket is the reason to choose this head over a slotted or cross head. A hexagon socket is sunk into the head, so it can be driven in a recess where there is no room for a driver to stand off, and it takes the torque a hard joint needs without deforming.
The trade is the seat. A tapered head is only as good as the countersink it goes into: on a plain hole the taper does nothing and the collar does all the work, and on a countersink cut at a different angle the head bears on a line. Both are worth stating on the drawing.
The recorded finish is colour zinc: a zinc plate with an iridescent passivation, which shows as a yellow-green sheen across the head. It is the standard bright finish for indoor steel fasteners and it is thin enough to leave the taper and the socket as formed.
| Finish | How it protects | Effect on taper and socket | Typical use |
|---|---|---|---|
| Colour zinc | Zinc with iridescent passivation | Thin; gauged after | Indoor equipment and panels |
| White zinc | Zinc with blue-white passivation | Thin; gauged after | Neutral indoor work |
| Black zinc | Zinc with black passivation | A few microns; socket re-checked | Dark panels |
| Zinc nickel | Alloy layer, higher corrosion resistance | Thicker; socket re-checked | Damp or industrial service |
| Stainless (equivalent part) | Alloy provides protection | No coating | Wash-down and coastal work |
The socket is where plating matters. Every micron narrows the hexagon, and a socket that has become tight after plating will not take the key to full depth — which on a steel head means the corners round instead of the screw turning. That is why the first article is driven with the production key after plating.
The taper is where the finish shows. Because the underside is a cone, the deposit lands at a different thickness on it than on a flat face, and a heavy coating can change the seat by enough to matter. Colour zinc at its normal thickness does not, which is part of why it is the recorded finish.
Three assemblies where a self-centring head and a recessed drive are both useful:
| Where it sits | The screw holds a cover in a countersunk hole where the head has to centre itself and finish near flush with the panel. |
| When it goes wrong | A flat head on a generous clearance hole sits off centre, and a head that is too tall fouls the next component. |
| Why it happens | The panel is thin, the fixings are in a row, and the head is visible. |
| What we control | Taper angle and collar diameter checked, socket driven with the production key. |
| Where it sits | The screw fixes a bracket into a machined seat where the head sits in a recess and the joint is tightened hard. |
| When it goes wrong | A cross recess rounds inside a small head, and a socket that is too shallow will not take the key to full depth. |
| Why it happens | The joint is tightened hard, the head is recessed, and the parts are machined. |
| What we control | Socket depth and collar height checked on the section, thread gauged per batch. |
| Where it sits | The screw fixes a plate or a mount where the head is seen and the fixing has to sit square in its seat. |
| When it goes wrong | An off-centre head shows in a row, and a bright silver head reads wrong against darker hardware. |
| Why it happens | The face is visible, the seat is machined, and the fixing repeats. |
| What we control | Collar and taper checked, tone matched to the sample, socket driven with the key. |
Four reasons that matter on a self-centring socket head, each tied to what the drawing has to prove:
|
Taper and seat reviewed together
The taper angle, the collar diameter and the socket depth are reviewed as one set against the seat, so a head that will not centre is raised before tooling. Basis: Taper and seat reviewed as one set. |
Head, taper and socket in one stroke
The collar, the taper and the hexagon socket are formed in one heading operation, so the taper stays concentric with the socket. Basis: Taper and socket formed together. |
|
Seat and socket checked on the part
The taper is checked in a sample seat, the collar on the projector, and the socket with the production key. Basis: First article seated and driven. |
First article to repeat production
Drawing revision, wire heat, die set and thread roll are fixed at the first article and used as the comparison for repeat orders. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these tapered socket head cap screws on a single-die header that upsets the collar and the taper and punches the hexagon socket in one stroke, then rolls the machine thread to a blunt chamfered end. The parts are colour zinc plated. The first part of every run is measured on the taper and the collar, seated in a sample countersink and driven with the production key, before the batch continues.
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The taper is the feature that has to be right first time. It is formed by the die and there is no machining step afterwards, so an angle that is slightly off cannot be corrected: the head will bear on a line and the collar will never sit flat. The taper is checked in a sample seat on the first article, not only on a projector.
What decides whether tapered socket head cap screws pass is the taper, the collar, the socket, the thread and the finish. The inspection agreement covers those, and the criteria come from the drawing.
Taper and collar on the projector |
Thread gauged after plating |
Hardness testing against the property class |
Salt-spray testing of the colour zinc plate |
The taper is checked by seating the first article and looking at the contact: a head that centres itself and leaves an even ring on the collar is a pass, and one that touches on the taper only has the wrong angle for that seat. The test is done in a sample countersink, because a taper measured on a projector can still be wrong for the seat it meets.
The socket is checked with the key at the joint torque. On a steel head the damage starts as a polish mark inside one flat, and that mark is what the inspection looks for before the corner actually rounds.
Every shipment of tapered socket head cap 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 a tapered head the first article is seated in the customer’s own countersink, because the taper only proves itself against the seat it meets. Buyers visit during the process to review samples and to see how the heads 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 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 head with a conical bearing face under an integral collar. The taper centres the screw in a matching countersink and the collar then sits flat to carry the load.
Yes. On a plain hole the taper does nothing and the collar carries everything; on a countersink cut at a different angle the head bears on a line.
The socket is recessed, so it drives where there is no room for a driver to stand off, and it takes more torque without rounding a small head.
From under the collar to the end. The taper depth belongs to the seat, not to the screw length.
Colour zinc with an iridescent passivation, which is thin enough to leave the taper and the socket as formed.
Thread size and pitch, taper angle, collar diameter and head height, socket size and depth, length and datum, material and finish.
How a tapered socket head cap screw project runs from drawing to repeat delivery:
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1
Send the drawing or a seat sample
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→ |
2
Taper and socket 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, taper angle, collar diameter and head height, socket size and depth, length and datum, material and finish.
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Thread and pitch
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Taper angle
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Collar diameter
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Socket size and depth
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Length and datum
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Finish
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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
