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:Stainless countersunk socket-slotted screw with nylon patch
Materials:Stainless steel
Surface treatment:Plain + Nylok patch (half circumference)
Head Type:Countersunk (flat) head
Drive type:Socket Slotted
Thread:Machine thread
Forming:Cold heading (one-piece)
Number:1801
We manufacture stainless countersunk socket-slotted screws with a nylon patch on half the thread, from M1.4 to M12 and up to 2,000 mm, cold-headed with the countersink and combined socket-slot recess formed in the die, then thread-rolled and patched. Head angle, recess size, patch position and material grade are made to 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.
A countersunk socket slotted screw is a machine screw with three features working together: a flat head that sinks into a countersunk hole until its face is level with the panel, a drive cut as a hex socket with a slot across it so either an Allen key or a flat screwdriver can turn it, and a nylon patch on part of the thread that stops the screw backing out under vibration.
Flush by geometry, not by force. The head angle has to match the countersink in the panel. A head cut at a different angle from the hole contacts on a ring instead of a face, so it sits high on one side, deforms the panel around the hole, and loses the flush finish the joint was designed for.
Two drives, one recess. Cutting a slot through the socket gives maintenance crews a second way in, but it also removes material from the socket walls. On a countersunk socket slotted screw the slot width and depth are dimensioned against the socket so the hex key still seats fully and neither drive strips under normal torque.
The patch is part of the thread. The nylon patch is applied to half the circumference and presses against the mating thread when the screw is driven, adding friction that resists loosening. It sits over the thread rather than in a drilled pellet hole, so the screw keeps its full thread section and can be adjusted after assembly.
Together these set what the screw does on site: it closes a panel flush, it can be driven with the tool that is on the bench, and it stays in place where vibration would walk a plain screw out.
These screws are formed by cold heading, not cut from bar. The head, the countersink and the socket-slot recess are formed in the die while the shank is upset in the same cycle, and the thread is rolled afterwards. Forming the recess instead of milling it keeps the grain running around the head, which is where a countersunk screw takes its load.
The nylon patch is applied after thread rolling and before packing: the thread is cleaned, masked to half the circumference, and the patch is fused onto the flank. Masking is what makes the half-circumference patch possible; a full ring would raise the driving torque on every screw and make the joint hard to assemble by hand.
Because the patch is a separate process step, it is also a separate control point. On a countersunk socket slotted screw, patch width, position along the thread and cure are set on the first article, and the prevailing torque it produces is measured before the batch is released. A patch that is too thin does not hold; one that is too thick will not let the screw reach the seated position.
Countersunk socket slotted screws are quoted from M1.4 to M12 and up to 2,000 mm, with length usually held to +0/-2 mm on the drawing. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission.
| Item | How it is defined | What we control |
|---|---|---|
| Total length | From the top face of the countersunk head to the tip | Datum stated on the drawing; length measured on the shop plate |
| Head diameter and angle | The cone that has to sit inside the panel countersink | Head angle and diameter checked against the countersink |
| Socket and slot | The combined recess that takes an Allen key or a flat driver | Slot width and depth held so neither drive strips |
| Thread length and position | Where the thread starts and how far it runs | Thread start checked against the drawing, not a sample |
| Patch width and position | How much of the thread carries the nylon patch | Patch masked to half the circumference, position set on the first article |
Each diameter and length combination is checked against the drawing before a quotation is issued. A short countersunk screw and a long one in the same thread class take different routes through heading and rolling, so the check confirms the route can hold the head angle and the thread start at the same time.
On a countersunk socket slotted screw, length is measured from the top face of the head, because that face is what ends up level with the panel. Head angle, head diameter and the depth of the countersink are gauged together on the first article, since a head that sits proud by a few hundredths is exactly the defect the flush design is meant to prevent.
For a countersunk socket slotted screw the drawing fixes five things: thread size and pitch, thread length and position, total length and its datum, right- or left-hand direction, and where the patch sits along the thread. A sixth line matters for stainless parts: the grade and the surface condition the parts are supplied in.
| Parameter | Why it matters on a socket slotted screw | What we control |
|---|---|---|
| Thread start position | It sets how much plain shank sits under the head before the thread engages | Start dimension checked on the first article and per batch |
| Engaging length | Too short leaves the joint weak; too long runs the thread through a thin panel | Thread length and position taken from the drawing |
| Patch position | The patch has to land in the engaged thread, not in the clearance hole | Patch masked to the engaged length on each drawing |
| Handedness | A left-hand thread on a right-hand assembly will not pull the joint closed | Direction marked on the part and on the packing |
A stainless countersunk socket slotted screw is supplied with the metal as the finish. There is no plated layer filling the recess or building up the thread, so the drives keep the dimensions they were formed to and the patch bonds to clean stainless rather than to a coating. What the part does need is a burr-free surface and passivation where the drawing calls for it, because free iron left in the recess is what starts corrosion.
| Finish | How it protects | Effect on recess and patch | Typical use |
|---|---|---|---|
| Plain / passivated stainless | Clean alloy surface, oxide film restored by passivation | No dimensional change; patch bonds to bare metal | Stainless assemblies, indoor and damp service |
| Electropolished stainless | Surface levelled and enriched in chromium | Recess edges smoothed; patch applied after polishing | Laboratory, hygienic and instrument equipment |
| Passivated plus light oil | Passive film plus a temporary barrier for transit | No dimensional change; oil cleaned before assembly | Parts stored before use |
| Zinc electroplated (carbon steel) | Sacrificial zinc layer | Patch applied over the plated thread; film thickness controlled | Carbon steel parts in dry indoor service |
| Dacromet flake (carbon steel) | Zinc-aluminium flake layer | Thin, even film; patch still bonds on the flank | Wet or outdoor carbon steel assemblies |
Plain stainless parts are checked for finish and cleanliness rather than salt spray; salt-spray exposure is agreed only where the drawing specifies a coating. The recess is cleaned after deburring so no cutting compound is left where the driver seats, and the patch is applied after that cleaning step, not before it.
Packing protects the head and the patch. Screws are packed in layers with the heads up, so the countersink does not rub against the carton and the patch is not flattened in transit. Batch and material information go on the label, so the part that arrives matches the record used for gauging.
Three assembly conditions where a countersunk socket slotted screw has to sit flush and stay put, and what it has to do instead:
Power tools and impact equipment
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Power tools – flush covers on a die-cast housing |
Hydraulic power units and pump skids
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Hydraulic power unit – flush cover plates |
Electric motors and gearmotor frames
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Electric motors – flush end shields and covers |
Four reasons that matter specifically on a countersunk socket slotted screw, each tied to what the drawing has to prove:
|
Engineering review before tooling
Head angle, recess size and patch position are settled before a die is cut, so the first sample is measured against the drawing instead of against a guess. Basis: Drawing or sample reviewed before tooling is released. |
Formed recess, rolled thread
The countersink and the socket-slot recess are formed in the die and the thread is rolled afterwards, so the head keeps its grain and the recess keeps its dimensions. Basis: Cold-heading and thread-rolling route on one-piece parts. |
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Both drives checked on the part
The socket is checked with the matching hex key and the slot with a flat driver, so the two ways into the recess are both usable, not just the one on the drawing. Basis: Socket and slot checked with their matching drivers. |
Patch applied and measured per batch
The nylon patch is masked, fused and checked for prevailing torque on the first article, so a repeat order behaves like the sample that was approved. Basis: Patch position and torque recorded per batch. |
These screws are formed, not assembled. Stainless wire goes through the heading aisle; the head, countersink and socket-slot recess are formed in one die, the thread is rolled, the part is deburred and passivated, and the nylon patch is applied before packing. The operator sets the die and checks the first parts against the drawing before the run is released.
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Between runs the die is changed to the drawing head form and length; the first parts go to the gauges before the run continues, and the setting is recorded. Patch batches are logged with the mask position and the torque check, so a repeat order can be compared with the first article rather than with a stored sample.
What decides whether a countersunk socket slotted screw passes is not its appearance: it is the head sitting in the countersink, the two drives taking the torque they were designed for, and the patch holding the screw where it was set. The inspection agreement covers those, and the criteria are the ones written on the drawing rather than a generic standard.
Thread gauging against GO/NO-GO gauges |
Head angle and profile on the optical projector |
Hardness testing of the base material |
Salt-spray testing where a coating is specified |
Each batch is recorded against the drawing revision: head angle and diameter from the first article, the socket checked with the hex key and the slot with a flat driver, thread gauging per batch, and the patch checked for position and prevailing torque. If a gauge or the patch check fails, the parts back to the last good setting are held and re-checked before anything ships.
Where the material needs a third-party report, it is specified on the drawing and filed with the batch, so the label and the inspection record carry the same number.
Every countersunk socket slotted screw shipment is traceable to the material it was made from. The grade, heat number and standard 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. 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. Buyers visit during the process to review samples and to see the forming, threading and finishing steps their parts will go through.
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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, the thread rolling and the patch 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 countersunk socket slotted screw is a machine screw with a flat countersunk head that sits flush in the panel, and a drive cut as a hex socket with a slot across it, so the screw can be turned with either an Allen key or a flat screwdriver.
The patch is fused onto half the thread circumference and presses against the mating thread when the screw is driven. That friction resists loosening under vibration, and because it sits on the thread rather than in a pellet hole, the screw can still be adjusted after assembly.
Countersunk socket slotted screws are quoted from M1.4 to M12 and up to 2,000 mm, with length usually held to +0/-2 mm. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission.
The head angle and diameter are gauged against the countersink in the drawing. A head cut at a different angle contacts on a ring instead of a face and sits proud, so the two are matched as a pair on the first article.
Either an Allen key in the socket or a flat screwdriver in the slot, with the matching size for the screw. Both are checked on the part with their matching drivers before the batch is released.
Thread size and pitch, thread length and position, total length and datum, head diameter and angle, socket size, slot width, patch width and position, material grade, surface condition, and quantity.
How a countersunk socket slotted screw project runs from drawing to repeat delivery:
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1
Send the drawing or sample
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→ |
2
DFM review and quotation
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→ |
3
First article approval
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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 countersunk socket slotted screw quotation, send the drawing with thread size and position, total length and datum, head diameter and angle, socket size, slot width, patch width and position, material grade and surface condition. Head, drives and patch are confirmed with you before production.
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Thread size, pitch and length
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Total length and datum
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Head diameter and angle
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Socket size and slot width
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Patch width and position
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Material grade and quantity
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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
