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 Screws
Materials:Carbon Steel
Surface treatment:Nickel Plated
Head Type:Pan head with integral flange
Drive:Phillips cross recess
Thread:Machine thread
Point:Plain, chamfered
Forming:Cold heading; thread rolled
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10
We make washer head screws in carbon steel with a nickel plate, an integral flange under a pan head and a Phillips recess, quoted to the drawing. The flange carries the bearing area instead of a loose washer, so the same clamp goes onto the panel every time, and the first article is checked on your panel.
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.
Washer head screws, also called pan collar head screws, have a pan-shaped head with an integral flange underneath that acts as the washer. The part recorded here is carbon steel with a nickel plate, with a Phillips recess, quoted from M1 upward and made to the drawing.
Pan head. A shallow dome with a cross recess, sized for a standard bit.
Integral flange. A wide collar under the head that spreads the clamp the way a washer would.
Machine thread. A thread that goes into a tapped hole or a nut, so the joint is repeatable.
They are used where a loose washer would be an extra part to fit, or an extra thing to lose, and where the bearing area has to be consistent from one assembly to the next. That second point is the one that matters in production: a washer that is picked up by hand is a washer that is sometimes not picked up.
A washer head screw does with one part what a pan head screw and a washer do with two. The flange under the head is machined or formed with the screw, so it cannot be left out, cannot be dropped, and cannot be fitted with the wrong inner diameter. On an assembly line where a washer is a separate bin, that is the difference between a joint that is always the same and one that depends on the operator.
What the flange gives is bearing area. A pan head bears on an annulus the width of its own rim; a washer head bears on an annulus that extends well beyond the head, which lowers the pressure on the panel and is what keeps a thin or soft part from being marked. The larger the flange, the lower the pressure for the same clamp.
The cost is diameter. A head with a flange is wider than the same thread with a plain pan head, so the clearance around the screw has to be larger, and the countersink or the spot-face in the customer part has to match the flange rather than the head. On a dense assembly that extra diameter is what decides whether parts touch.
The flange also has its own geometry to control. Its face has to be flat and square to the thread, because it is the surface that bears; if it is dished or tapered, the load goes to one side and the panel marks unevenly. The transition from the flange into the head has to be a radius rather than a sharp step, because that is where the head bends under load.
And the flange diameter is fixed. A loose washer can be chosen for each joint — a larger one for a soft panel, a smaller one where space is tight — while an integral flange is whatever the screw was made with. That is the trade: fewer parts and more consistency, against less freedom to tune the joint.
The part is quoted to the drawing with the head, the flange and the thread stated separately. Custom lengths up to 2,000 mm, subject to DFM review after drawing submission. The quotation for washer head screws carries the head diameter and height, the flange diameter and thickness, the recess, the thread, and the hole or nut it goes into.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Pan head | Diameter, height and recess |
| Flange | Integral washer face | Diameter, thickness and flatness |
| Thread | Machine thread | Size, pitch and length |
| Bearing area | Flange annulus | Diameter and face condition |
| Recess | Phillips | Depth and width |
| Hole | In the customer part | Clearance for the flange |
The flange diameter is the dimension that changes the joint. It has to clear whatever is around the screw, and it has to be large enough for the panel it bears on; those two constraints are set by the customer’s part rather than by the screw alone.
The flange face is either flat or slightly undercut, depending on the drawing. A face that is meant to be flat is checked for flatness, and one that is undercut is checked for the diameter of the contact ring, because those two designs bear differently.
The recess and the head height are agreed together, since a pan head has to leave enough material for the cross after the flange has taken its share of the head diameter.
Four properties decide washer head screws, and each one carries a cost:
| Property | What it gives | What it costs |
|---|---|---|
| Integral flange | One part instead of two | Larger head diameter |
| Bearing area | Lower pressure on thin panels | Flange diameter cannot be tuned |
| Pan head with cross | A standard bit and a flat seat | Height above the surface |
| Nickel plate | Bright, hard, thin film | No sacrificial protection at a scratch |
The value is consistency. The bearing area is the same on every screw in the batch, so a panel that is marked by one is marked by all, and a joint that is right once stays right through a production run.
The cost is space. The flange needs a clear area around the hole, and on a small or crowded part that area is what limits the head size, which is why the flange diameter is agreed with the customer rather than chosen from a table.
The recorded finish is nickel plated over carbon steel. It gives a bright, hard surface with a thin film, so the flange keeps its diameter and its face while the part resists wear at the bearing ring, and it suits visible hardware.
| Option | How it protects | Effect on flange and recess | Typical use |
|---|---|---|---|
| Nickel plated | Hard bright barrier | Thin build; flange diameter kept | Visible hardware |
| Clear zinc | Sacrificial zinc | Build on flange; re-checked | General indoor work |
| Colour zinc | Sacrificial zinc, tinted | Build; flange and recess checked | Matched appliances |
| Black oxide | Conversion film, oiled | No measurable build | Dark mechanisms |
| Stainless, passivated | Passive film, no coating | No build; different material | Wet and food areas |
On a washer head the flange is the surface that bears, so a coating on it is a film under the load. A hard plate like nickel holds up under that load; a soft zinc layer can be marked where the flange meets the panel, and the mark is visible on a light part.
The recess is the other place the plate matters. A heavy layer inside the cross changes which bit seats, and on a washer head the recess is set into a head that has already given its diameter to the flange, so there is little margin.
Three assemblies where the washer has to be part of the screw:
| Where it sits | The screw holds a cover or a panel where the material marks easily under a small head. |
| When it goes wrong | The panel dishes around the screw, or the paint is cut by the head edge. |
| Why it happens | The bearing area is too small for the clamp, and no washer is fitted. |
| What we control | Flange diameter and face checked; first article assembled on the panel. |
| Where it sits | The screw holds a trim, a bracket or a liner where a loose washer would be a separate operation. |
| When it goes wrong | A washer is missing, and the joint marks the surface. |
| Why it happens | The assembly relies on a loose part being picked up every time. |
| What we control | Flange diameter and thread checked; first article assembled without a washer. |
| Where it sits | The screw fixes a plate or a cover where the joint sits on a painted or plated surface. |
| When it goes wrong | The finish is damaged around the screw, or the joint loosens. |
| Why it happens | The head pressure is high, and the surface is soft. |
| What we control | Flange face and recess checked; first article assembled on the finished panel. |
Four reasons that matter on a part where the washer and the screw have to behave as one, each tied to something the drawing or the first article proves. All four show in the sample.
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Flange and head stated separately
The drawing states the flange diameter and thickness as well as the head, because on a washer head the flange is the bearing surface. Basis: Flange dimensioned. |
Flange formed with the head
The flange is formed in the same setup as the head, so its face runs square to the thread rather than being added in a second operation. Basis: Flange square to thread. |
|
Joint proved on the panel
The first article is assembled on the customer panel, because the bearing area and the marking only show in the joint. Basis: Joint proved on panel. |
Same bearing area each time
Flange diameter, face flatness and plate are recorded with the drawing revision, so a repeat batch bears the same way. Basis: Same flange across orders. |
These screws are cold headed from carbon steel wire, with the pan head and the flange formed together, the recess cut and the thread rolled; the parts are then nickel plated. The first piece of every run is measured on head diameter and height, flange diameter and thickness, flange face flatness, recess depth and thread.
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The flange and the head are formed in one die, so the flange face comes out square to the axis of the shank. If the flange were formed in a second operation, it would be possible for the face to sit at a slight angle, and a screw whose flange is out of square marks a panel on one side only.
The recess is cut after heading, with its depth taken from the finished head face. On a washer head the material above the flange is limited, so a recess that is too deep leaves a thin section exactly where the head bends.
The thread is rolled after heading, and the plating comes last. Because the flange is the bearing surface, its diameter and its face are checked again after plating on a sample from each lot, since a heavy layer on a wide flange changes the contact ring.
What decides whether washer head screws pass is the flange, its face and the thread. The inspection agreement covers those, and the criteria come from the drawing.
Flange and head on the projector |
Thread gauged |
Core hardness checked |
Salt-spray testing where plated |
The flange is measured for diameter and thickness, and its face for flatness and squareness to the thread. A flange that is out of square does not show until the screw is tightened on a panel, and then it shows as a crescent-shaped mark.
The head is checked for diameter, height and the recess, and the transition from the flange into the head for a radius rather than a step. That radius is what keeps the head from cracking when the screw is pulled hard.
The thread is gauged, and a sample is assembled on a panel of the customer’s material to confirm that the flange bears over its full face and does not cut the surface. The mark on the panel is the outcome that matters on a washer head.
Every batch of washer head screws is traceable to the wire it was made from and to the plating lot that finished it. The grade and heat number appear on the material certificate supplied with the parts, and the plating report carries the layer thickness and the lot number.
ISO 9001:2015 |
RoHS test report |
Registered trademark |
Patent: security screw and driver |
With each shipment we supply the material certificate, the inspection record for the dimensions on the drawing, including the flange and the recess, and the plating report. The records carry the drawing revision and the batch number, so a repeat order of washer head screws bears on the panel the same way.
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 assembled on the customer panel, because the flange leaves a mark and the mark is what the customer sees. Buyers visit during the process to review samples.
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8,678+
customers served
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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 heading cell 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 loose washer. It gives the same bearing area without a separate part to fit, and it cannot be left out.
A pan head bears on its own rim only. On a thin or soft panel that marks the surface, and the flange spreads the clamp.
Diameter. The head is wider than a pan head of the same thread, so it needs more clearance around it.
No. It is fixed by the screw, unlike a loose washer, which is why the flange diameter is agreed against the panel.
It does. The flange is the bearing surface, so a hard plate holds up under load and a soft one can mark the panel.
Head diameter and height, flange diameter and thickness, recess, thread size and length, and the clearance and panel.
How a washer head screw project runs from drawing to repeat delivery:
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1
Send the drawing and the panel
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→ |
2
Flange diameter and thread agreed
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→ |
3
First article assembled on the panel
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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 head diameter and height, flange diameter and thickness, recess, thread size and length, and the clearance and panel the screw bears on.
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Head size
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Flange diameter
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Flange thickness
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Recess
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Thread
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Panel
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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
