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:Washer head machine screw, integral collar, hexagon socket drive, full thread (Non-Standard)
Materials:Carbon Steel
Surface treatment:Nickel Plated (bright, environmentally controlled process)
Head Type:Pan washer head: low pan dome with a wide thin integral collar formed from the same wire; the flat underside of the collar is the bearing face; no separate washer
Drive:Internal hexagon (Allen) socket, six flats, flat bottom
Thread:Machine thread, rolled 60 degrees, full length from the collar underside to the end; no plain shank
Point:Blunt end with a small chamfer; no taper, no drill point
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Forming:Single-die cold heading, thread rolling, nickel plating, sorting
Number:786
We manufacture washer head machine screws with an integral collar and a hexagon socket drive, a full machine thread from the collar underside and a blunt chamfered end, in carbon steel with bright nickel. Collar diameter and thickness, socket, thread 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.
Washer head machine screws are machine screws whose head carries an integral collar, so the bearing area of a washer comes with the screw and there is no separate part to fit. The recorded item on this page combines that head with an internal hexagon socket, a full machine thread from the collar underside and a blunt chamfered end, in carbon steel with bright nickel, quoted from M1 to M14 with Number 786.
Integral collar. A wide thin collar is formed from the same wire as the head, and its flat underside is the bearing face. Because it is formed rather than pressed on, it cannot rotate, fall off or be left out, and it spreads the clamp load out to its edge.
Internal hexagon socket. Six flats with a flat bottom, driven with an Allen key. The socket takes more torque than a cross recess of the same head size, and it does not cam out, so the drive goes into the thread rather than into the bit tip.
Full machine thread. The thread runs from the collar underside to the end, with no plain shank, so the whole length below the head engages a tapped hole or a nut. Machine screws of this form are for engineered joints, not for cutting their own thread.
Blunt end. There is no point: the screw goes into a tapped hole and stops where the thread ends. The chamfer lets the first thread enter cleanly.
Bright nickel. A hard decorative deposit on carbon steel. It suits a visible washer head, because the collar is a large flat face that shows the finish evenly.
The pan dome and the integral collar are upset in one heading stroke, and the hexagon socket is formed in the same stroke or immediately after it, so the socket stays concentric with the shank and with the collar. On a washer head that concentricity is what keeps the collar sitting flat instead of tilting on one side.
The collar is thin by design. A thin collar follows the surface it bears on and spreads the load, which is the point of the feature; a thick one would be stiffer but would also raise the head and add weight. The trade is that a thin collar can dish under heavy torque, so washer head machine screws of this type are tightened to a stated torque rather than to a feel.
The socket depth is set against the head height. A socket that is too shallow bottoms out on the key and rounds the corners; one that is too deep cuts into the material that carries the head load, and on a washer head the material above the collar is already thin.
The thread is rolled from the collar underside to the end, so there is no plain shank. Rolling work-hardens the flank, which matters on a screw that may be removed and refitted, and it leaves a thread that gauges consistently along the whole length.
Nickel plating follows rolling. The deposit covers the socket as well as the thread, so the socket is checked with the key after plating and the thread is gauged in the plated condition — the two results that matter to the customer.
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; washer head machine screws run from the small instrument sizes up to the heavier equipment sizes, and the collar diameter grows with the thread.
| Item | How it is defined | What we control |
|---|---|---|
| Thread | Metric machine thread, rolled, full length | Gauged per batch after plating |
| Head dome | Low pan dome above the collar | Checked on the projector |
| Collar diameter | Wide and thin, integral with the head | Measured on the first article |
| Collar thickness | Thin enough to follow the surface | Checked on the section |
| Socket | Internal hexagon, six flats | Checked with the key after plating |
| End | Blunt with a small chamfer | Checked on the first article |
| Length | From the collar underside to the end | Measured on the shop plate |
Length is measured from the collar underside, because that is the face that bears on the part. It is not the same as measuring from the dome: the collar adds its own thickness, and on a shallow counterbore that difference decides whether the screw bottoms before the collar seats.
The collar diameter is the dimension that decides both the bearing area and whether the fixing fits. A wider collar spreads the load further and covers an oversized hole; it also needs clearance around the head and leaves a wider footprint on a visible face. It is quoted with the head diameter rather than left to the standard.
A washer head with a socket drive is a deliberate combination: the head is chosen for bearing area, the drive is chosen for torque. Together they suit a joint that has to be tightened hard on a soft or thin part.
| Feature | What it gives | What it costs |
|---|---|---|
| Integral collar | Bearing area without a loose washer | Cannot be changed; a damaged collar scraps the screw |
| Hexagon socket | High torque, no cam-out | Needs an Allen key; socket rounds if the key is worn |
| Full thread | Engagement over the whole length | No plain shank to centre the screw in a bore |
| Blunt end | Stops at the thread end in a tapped hole | Cannot start in an unthreaded hole |
| Bright nickel | Hard, even finish on the collar face | Deposit narrows the socket; re-checked after plating |
The socket is what makes the collar usable. A washer head fixed with a cross recess can only be driven so hard before the cross gives up, and on a thin panel the collar needs more torque than that to seat firmly. A six-flat socket transmits the torque without wedging the bit out, so the joint can be tightened until the collar bears all round.
The collar is what makes the socket safe to use. The socket concentrates load in the head, and a head that bears on a narrow ring transfers that load into a small patch of panel; the collar spreads it. Neither feature works as well alone, which is why washer head machine screws with a socket drive are specified for thin or soft parts that have to be tightened properly.
The recorded finish is bright nickel, applied after the thread is rolled. Nickel is hard and takes a polish, and on a washer head it gives an even face across the collar, which is the part of the screw a customer sees.
| Finish | How it protects | Effect on socket and thread | Typical use |
|---|---|---|---|
| Bright nickel | Hard metallic deposit, decorative | A few microns; socket and thread re-checked | Visible equipment and instruments |
| White zinc | Sacrificial zinc, blue-white passivation | Thin; thread gauged after | General indoor assembly |
| Zinc nickel | Alloy layer, higher corrosion resistance | Thicker; socket re-checked | Wet or industrial service |
| Black oxide | Thin conversion film, oiled | Almost no change | Dark indoor assemblies |
| Stainless (equivalent part) | Alloy provides protection | No coating | Wash-down and coastal work |
The socket is the feature most sensitive to coating. A deposit on six flats changes the across-flats dimension and the depth, so a socket that measured correct before plating can refuse the key afterwards. That is why the socket is checked with the production key after plating and not with a gauge on a bare part.
On a visible washer head the collar face is judged like a decorative surface: scratches, uneven colour and a burr at the edge all show. Nickel is harder than zinc and holds up better to handling, which is why it is used on equipment where the fixings are seen rather than buried.
Three assemblies where a wide bearing face and a high-torque drive are both needed:
| Where it sits | The screw fixes a panel, a bracket or a component to a thin face where the head is seen and a narrow head would dish the surface. |
| When it goes wrong | A cross recess cannot be tightened enough to seat the collar, and a narrow head leaves a ring mark on the panel. |
| Why it happens | The panel is thin, the face is visible, and the joint is tightened on a line. |
| What we control | Collar diameter and thickness checked, socket driven with the production key after plating. |
| Where it sits | The screw holds a component to a formed sheet bracket where the load has to be spread and the joint is opened for service. |
| When it goes wrong | A plain head concentrates load and deforms the sheet, and a washer that is added by hand can be left out. |
| Why it happens | The sheet is thin, the joint is serviced, and the fixing sits in a counterbore. |
| What we control | Collar flatness checked before and after driving, thread gauged per batch. |
| Where it sits | The screw closes a cover that is removed regularly, where the head has to take repeated tightening without rounding and the collar protects the paint. |
| When it goes wrong | A worn cross recess rounds on the first dozen openings, and a head without a collar scars the paint at every service. |
| Why it happens | The cover is opened often, the paint is visible, and the fixing is on the outside. |
| What we control | Socket checked with the key at the joint torque, collar checked for burr, first article assembled. |
Four reasons that matter on a socket-driven washer head, each tied to what the drawing has to prove:
|
Collar and socket reviewed together
The collar diameter and thickness, the socket depth and the head height are reviewed as one set, so a head that will not take the key after plating is raised first. Basis: Collar and socket reviewed as one set. |
Head, collar and socket in one route
The pan dome, the integral collar and the hexagon socket are formed in one heading route, so the socket stays concentric with the collar. Basis: Collar and socket formed in one route. |
|
Socket and collar checked on the part
The socket is checked with the production key after plating, and the collar for flatness and burr on the first article. Basis: First article driven with the production key. |
First article to repeat production
The first article fixes the drawing revision, wire heat, die set, thread roll and plating thickness; repeat orders are compared against that record. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these washer head machine screws on a single-die header that upsets the pan dome, the integral collar and the hexagon socket, then rolls the machine thread from the collar underside to a blunt chamfered end. The parts are bright nickel plated. The first part of every run is measured on the collar, checked with the production key and driven into a sample joint, before the batch continues.
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The collar is the feature that has to be perfect before plating, because after plating there is nothing left to correct. A collar that is slightly thicker on one side will dish unevenly under torque, and the head will lean — a defect that reads as a loose joint and cannot be seen on a bench. It is checked on the section of the first article and sampled through the run.
What decides whether washer head machine screws pass is the collar, the head, the socket, the thread and the plating. The inspection agreement covers those, and the criteria come from the drawing.
Collar and dome on the projector |
Thread gauged after plating |
Hardness testing against the property class |
Salt-spray testing of the nickel plate |
The socket is checked by driving at the joint torque with the production key and then inspecting the flats for deformation. A socket that measures correct and still rounds under load was either too shallow or too rough at the bottom, and neither shows on a gauge.
The collar is checked for flatness before and after that drive. A collar that is flat on the bench and dished after tightening has told you the joint torque is above what that collar thickness will take, and the answer is a thicker collar or a lower torque — not a longer key.
Every shipment of washer head machine 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 washer head the first article is driven at the joint torque and the collar checked afterwards, because the bearing face is what the part is for. 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 machine screw with a wide thin collar formed into the head. The collar underside is the bearing face, so the bearing area of a washer comes without a separate washer.
A hexagon socket takes more torque and does not cam out. On a thin panel the collar needs more torque to seat than a cross recess can transmit.
It replaces a flat washer for spreading load, but it is softer and thinner than a hardened washer. For high preload or a damaged surface, a separate hardened washer is still the right answer.
From the collar underside to the end. The collar adds its own thickness, so a counterbore has to allow for it.
The deposit changes the across-flats dimension and the depth. A socket that passes before plating can refuse the key afterwards.
Thread size and pitch, head and collar diameter, collar thickness, socket size, length and datum, material, plating and joint torque.
How a washer head machine screw project runs from drawing to repeat delivery:
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1
Send the drawing or sample
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→ |
2
Collar and socket review
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→ |
3
First article driven at joint torque
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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 and collar diameter, collar thickness, socket size, length and datum, material, plating and the joint torque.
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Thread and pitch
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Head and collar
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Collar thickness
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Socket size
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Length and datum
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Joint torque
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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
