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+86 13143444311
Email：sst@szsst88.com
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Address：Building 9, First Industrial Zone, Tantou Industrial City, Songgang Street, Baoan District, Shenzhen 518105, Guangdong, China
Type:Low Profile Socket Head Screws
Materials:304 Stainless Steel
Surface treatment:Plain
Head Type:Low profile socket cap head
Drive:Hexagon socket (Allen)
Thread:Machine thread
Point:Plain, chamfered
Forming:Single Die Heading
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10
We make low profile socket head screws in 304 stainless steel, quoting them from M1 to M10 with lengths made to the drawing. The reduced head height and the socket depth are agreed as one pair, the socket is proved with your key, and the first article is fitted into your assembly.
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.
Low profile socket head screws are socket head cap screws with the head height reduced, driven with a hex key from a recess in the head. The part recorded here is 304 stainless steel, plain finish, quoted from M1 to M10 with lengths made to the drawing.
Low head. A cylindrical head roughly half the height of a standard cap head, so the fixing stands less proud of the part.
Hexagon socket. A hexagonal recess driven by an Allen key, sized against the thread diameter.
304 stainless. An austenitic grade that resists indoor corrosion, is non-magnetic in the annealed state and cannot be hardened by heat treatment.
Machine thread. A uniform thread for a tapped hole or a nut, with the length measured over the head.
They are used where a standard socket head would foul a cover, a sliding part or a recessed pocket: small mechanisms, instrument frames, covers with tight clearance and assemblies where the head must sit below a moving surface.
On a standard socket head cap screw the head height and the socket depth are generous, because the head is designed to carry the preload of a high-strength joint. A low profile head keeps the same thread and the same drive style, and takes away the material that did both of those jobs at once.
The first consequence is drive depth. Reducing head height reduces how deep the hexagon can go, so a standard key enters only part of the way. That is why a low profile socket head screw is driven with a short-arm or a long-reach key that reaches the floor of the recess: a key that only engages the top of the socket bears on a fraction of the walls, and in stainless steel the corners round before the joint tightens.
The second consequence is load. The head carries the clamp load through its bearing face and distributes it into the socket walls. A shallower head has less material in that path, so the same torque puts more stress into the same volume, and the socket is the first place that shows it. On a low head the sensible torque is lower than on the standard head of the same diameter, which is a design decision rather than a workshop preference.
The third is clearance. A low head exists to fit. The gain in height has to be paid for in socket depth and in bearing area, and the part that benefits is whatever moves past the fixing: a cover, a lever, a sliding plate. Where the assembly has room for a standard head, there is no reason to use a low one.
Stainless adds the last variable. 304 work-hardens, so the socket walls get harder as they deform; a key that slips once leaves a polished, slightly work-hardened surface that slips more easily the next time. The socket does not fail suddenly, it degrades, and that is why the key fit matters more here than on a plated steel part.
The recorded range is M1 to M10, with lengths made to the drawing. Custom lengths up to 2,000 mm are subject to the drawing submission and DFM review. The quotation for a low profile socket head screw carries the head diameter and height, the socket size and depth, the thread pitch and the overall length.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Cylindrical, low height | Diameter and reduced height |
| Socket | Hexagon, key size per diameter | Depth and wall thickness |
| Bearing face | Flat under the head | Flatness and edge radius |
| Thread | Machine thread in 304 | Pitch, length and start position |
| Length | Overall, head included | Length tolerance and thread start |
| Finish | Plain, passivated | No build; socket as cut |
Head height is the defining dimension and the one that has to be measured with the socket, not separately: a head pressed slightly low leaves less depth for the hexagon, and the part can pass a height check while the socket is too shallow for the key.
Socket size follows the thread diameter, but the depth does not have to. Where the drawing allows, the socket is kept as deep as the head permits, and the key is chosen to reach the floor. That combination is what a low head needs to be driveable at all.
Because these parts are common in the small sizes, the M1 to M3 range is where the tolerance matters most: a socket in a 1.5 mm head has very little material around it, and a burr or a slightly off-centre cut shows as a socket that will not take the key.
Four properties decide a low profile socket head screw, and each one carries a cost:
| Property | What it gives | What it costs |
|---|---|---|
| Low head | Clears covers and moving parts | Less material for the socket |
| Hexagon socket | High torque in a small head | Shallow engagement in a low head |
| 304 stainless | Corrosion resistance indoors | Work-hardens; socket degrades on slip |
| Flat bearing face | Clamp load spread on the part | Needs a flat seat, not a cast surface |
The value is that it solves a clearance problem without changing the thread, the material or the tooling. A standard cap screw in the same thread would be stronger, but it would not fit, and a low head is the part that lets a robust thread stay in the design.
The cost is drive reliability. A reduced head gives a reduced socket, and the torque that the thread could take is no longer the limit: the socket is. That has to be recognised at the design stage rather than found on the assembly line.
The recorded finish is plain over 304 stainless. There is no plating to fill the socket or change the key fit, and the surface protection is the alloy itself plus the passivation that follows heading and thread rolling.
| Option | What it does | Effect on head and socket | Typical use |
|---|---|---|---|
| Passivated, plain | Removes free iron; rebuilds oxide | No build; socket as cut | Default for stainless |
| Electropolished | Levels the surface | Socket edges rounded slightly | Medical and food equipment |
| Black oxide on stainless | Colours the surface | Thin film; key fit unchanged | Dark instrument panels |
| Nickel or chrome plated | Hard barrier deposit | Build measurable; socket re-gauged | Where a bright finish is wanted |
Passivation matters more on a socket head than on a pan head, because the socket is a cut feature with several internal corners where free iron is left behind. A batch that was not properly passivated shows rust first inside the socket, which is the place that then damages the key.
Where a plated finish is used on these parts, the socket is gauged after plating. A low head has little depth to give, and a coating that adds a measurable thickness inside the hexagon changes which key seats properly.
Three settings where the head has to clear something:
| Where it sits | The screw holds a frame where a standard head would foul a cover that slides over it. |
| When it goes wrong | The cover binds on the heads and the panel does not sit flat. |
| Why it happens | The head is inside a recess, the cover moves, and the joint is serviced. |
| What we control | Head height and socket depth checked; first article fitted with the cover. |
| Where it sits | The screw fixes a bracket where the fixing must sit below a moving part. |
| When it goes wrong | A proud head wears on the moving surface and the mechanism stiffens. |
| Why it happens | The clearance is tight, the part moves, and the fixing is repeated. |
| What we control | Height measured to the drawing; first article cycled with the mechanism. |
| Where it sits | The screw closes a plate where the pocket is machined to a depth that leaves no room for a standard head. |
| When it goes wrong | The head touches the pocket floor before the joint is tight. |
| Why it happens | The pocket depth is fixed, the plate is machined, and the joint is assembled dry. |
| What we control | Height and bearing face checked; first article fitted in the pocket. |
Four reasons that matter on a part where the socket is the weak point, each tied to something the drawing has to prove:
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Height and socket agreed together
The reduced head height and the socket depth are agreed as one pair, because a head that is a little low leaves a socket that will not take a standard key. Basis: Height and socket as one pair. |
Headed, broached, threaded and passivated
The head is formed in one stroke, the hexagon broached to depth, the thread rolled, and the batch passivated after forming. Basis: One route from wire to socket screw. |
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Socket proved with the production key
The socket is measured and driven with the key the customer will use, because on a low head the difference between engaging and rounding is a fraction of a millimetre. Basis: Socket driven with your key. |
Same key, same result
The broaching tool and the socket depth are recorded with the drawing revision, so a repeat order takes the same key with the same engagement. Basis: Key fit held across orders. |
These screws are headed on single-die machines that form the low head in one stroke, broached with a hexagonal punch, thread rolled on the 304 shank, and passivated as a batch. The first part of every run is measured on head diameter and height, socket size and depth, thread and length, and driven with the key the customer uses.
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Broaching the socket is the step that decides the part. The punch is driven into the head and displaces material outwards, so a low head has to be formed slightly fuller than its finished height to leave enough metal around the socket walls. If the head is pressed too thin, the socket walls come out with less material on one side and the key bears on two faces instead of six.
Stainless steel makes that less forgiving. It work-hardens under the punch, so the socket walls are harder than the rest of the head and the punch has to be replaced before it dulls enough to tear the corners. The interval is kept in the tooling record, and the depth is checked on the first part after every change rather than at the end of the run.
Passivation comes last, and on these parts it is checked inside the socket as well as on the outside. Free iron collects in the hexagon corners during broaching, and a batch that is passivated on the outside only will show rust first at the point the key touches.
What decides whether low profile socket head screws pass is the head, the socket, the thread and the surface. The inspection agreement covers those, and the criteria come from the drawing.
Head height and socket on the projector |
Thread and start checked |
Hardness against the 304 spec |
Salt-spray testing of the passivated socket |
Head height is measured together with socket depth, because the two come out of the same forming and broaching sequence. The bearing face flatness is checked on the same setup, since a face that is not flat loads the socket unevenly when the head is pulled down.
The socket is proved by driving it with the key at the torque the joint calls for, then inspecting the corners under magnification. On 304 that check is what separates a socket that has been cut to size from one that has been cut slightly small, because both accept the key and only one survives a service cycle.
A sample from every batch is assembled into the customer part and taken apart, which shows a head that fouls, a key that does not reach the floor, or a socket that has started to mark.
Every batch is traceable to the heat of 304 stainless it was made from. The grade and heat number appear 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 shipment we supply the material certificate, the inspection record for the dimensions on the drawing including the head height and socket depth, and the passivation records for the batch. The documents carry the drawing revision and the batch number, so a repeat order keeps the same socket engagement.
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 low profile socket head screws the first article is fitted into the customer assembly with the cover or mechanism in place. 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 headers and the broaching station 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 |
The head is shorter, so there is less material for the hexagon. The key has to reach the floor of the recess, and a shorter socket leaves less room for error.
The key size that matches the socket, used short-arm or long-reach so it seats to the bottom. A key that only enters part way will round the corners.
For instrument and small mechanism joints yes. 304 work-hardens but cannot be heat treated, so a joint designed for a high-strength steel screw needs a different grade or a bigger diameter.
Less than a thin washer edge but more than a standard cap head, because the bearing area is smaller. A flat seat and the right torque keep the mark inside the head diameter.
Indoors they are fine. In coastal air the molybdenum-bearing grade is the better choice, and the socket is the first place corrosion shows.
Head diameter and reduced height, socket size and depth, thread pitch and overall length.
How a low profile socket screw project runs from drawing to repeat delivery:
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1
Send the drawing and the clearance limit
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→ |
2
Head height and socket agreed
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→ |
3
First article fitted with your key
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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, socket size and depth, thread pitch and overall length.
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Head diameter
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Reduced height
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Socket size
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Socket depth
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Thread pitch
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Length
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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
