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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:Stainless Steel Fasteners
Materials:Stainless Steel
Surface treatment:Plain
Head Type:Hexagon head
Drive:External hex (wrench or socket)
Thread:Machine thread
Point:Plain, chamfered
Forming:Formed and threaded; face machined
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10
We make stainless steel fasteners in the hexagon head form, quoted with head across flats, thread, length and the clearance the wrench needs. An external hex takes high torque and a wide bearing face, but it has to be reached and swung, so the space around the head is part of the 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.
Stainless steel fasteners are screws and bolts made in a stainless grade, used where rust on the fixing would be a problem. The part recorded here is a hexagon head screw in stainless steel, left plain, quoted in metric sizes from M1 upward.
Hexagon head. An external hexagon that a wrench or a socket drives from outside the head.
Machine thread. A thread of constant form that goes into a tapped hole or a nut.
Stainless body. No coating to chip, and no rust where the joint is handled or washed.
They are used in frames, brackets and outdoor equipment, where the fastener is structural and the environment is not kind to plated steel. Stainless steel fasteners of this form are also chosen where the joint will be opened during service and the head has to stay workable after a season outside, because a fastener that cannot be undone is not a serviceable one.
A hex head fastener takes its drive on the outside of the head. That is the whole difference from a socket screw, and it decides how the joint is designed rather than how the screw is made. The wrench has to reach the flats, and it has to swing, so the space around the head is part of the specification: a hex head needs a clear circle wide enough for the socket and a radius wide enough to turn it.
In exchange it can take more torque. An external hexagon surrounds the head rather than sitting inside it, so the head does not have to give up material to a recess, and the wrench engages the full height of the flats. On a structural joint that is what allows a higher preload without the drive becoming the limit.
The head diameter follows. A hex head is larger than a socket head of the same thread, which matters in two directions: it bears on a wider annulus, which is good on a soft part, and it needs more clearance around itself, which is bad in a compact assembly. That trade is why the same thread appears in both forms, and why choosing between them is a decision about the space rather than about the load.
The head is also what a bolt is judged by. In the standards, a fastener turned by a nut and driven from a hexagon head is a bolt, while one driven into a threaded hole is a screw. The distinction matters for the load path: a bolt with a nut develops its clamp across the joined parts, where a screw develops it in the last part only.
Stainless is the natural material for these parts. It removes the coating question from the joint, and on outdoor equipment it is the difference between a fastener that stays as made and one that shows rust at the first scratch.
The part is quoted to the drawing with the head, the drive and the thread stated separately. Custom lengths up to 2,000 mm, subject to DFM review after drawing submission. The quotation for stainless steel fasteners carries the head across flats and height, the thread, the length, the grade, and the clearance around the head in the customer part.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Hexagon head | Across flats, height and bearing face |
| Drive | External hex | Across flats and corner clearance |
| Thread | Machine thread | Size, pitch and length |
| Clearance | Space around the head | Wrench swing agreed |
| Grade | Stainless steel | Alloy and finish |
| Mating part | Customer part | Nut or tapped hole and depth |
On stainless steel fasteners of this form the across-flats dimension sets the wrench, and the corner radius is what the socket has to clear. On a dense assembly the clearance around the head, not the thread, is the dimension that decides whether the fastener can be installed at all.
On these stainless steel fasteners the head height is the bearing surface. On a hex head the underside is a flat annulus, and a bent or dished face loads one side of the joint.
The thread and the mating part are agreed as a pair. On a bolted joint the clamp is developed across the parts, so the nut and the thread engagement are part of the specification rather than an accessory.
Four properties decide stainless steel fasteners of this form, and each one carries a cost:
| Property | What it gives | What it costs |
|---|---|---|
| Hexagon head | High torque from a wrench | Needs swing clearance around it |
| Larger head | A wide bearing face | Takes space in a compact assembly |
| Machine thread | A defined, repeatable clamp | Needs a nut or tapped hole |
| Stainless body | No rust without a coating | Galling on stainless threads |
The value of stainless steel fasteners is a fixing that can be tightened hard and left outside. On a frame or a bracket, that combination is what makes a stainless hex head the default choice.
The cost is the space it needs and the material it is made from. A hex head will not fit where a socket head does, and a stainless joint may need a lubricant to reach its clamp.
The recorded finish is plain stainless steel. On a hex head that keeps the flats at their size and the bearing face flat, and it avoids a plate that would sit between the head and the part.
| Option | How it protects | Effect on head and thread | Typical use |
|---|---|---|---|
| Plain, passivated | Passive film, no coating | Flats and thread as made | Frames and outdoor hardware |
| Passivated 316 | Higher alloy passive layer | No build; better in chlorides | Marine and chemical plant |
| Dry film lubricant | Low-friction film | Thin; reduces galling | Serviced stainless joints |
| Nickel plated steel | Hard bright barrier | Build; thread re-gauged | Cost-driven indoor work |
| Bead blasted | Matte, uniform surface | Can round the head corners | Decorative architectural |
On stainless steel fasteners with a hex head the flats are the drive, so any finish that changes them changes which wrench fits. Plain stainless keeps the across-flats as machined, which is why it is usual on structural parts.
A lubricant is the treatment that addresses the joint rather than the appearance. Stainless against stainless can gall, and on a hex head that shows as a fastener that will not reach its torque or will not come out again.
Three assemblies where a structure has to be held and left outside:
| Where it sits | The fastener joins brackets and beams that carry load and are exposed to weather. |
| When it goes wrong | The joint loosens, or the fastener seizes before it is tight. |
| Why it happens | The clamp is developed across the parts, and the engagement or lubrication is short. |
| What we control | Thread, engagement and lubricant agreed; first article assembled and loaded. |
| Where it sits | The fastener holds covers and fittings where a plated screw would fail within a season. |
| When it goes wrong | Rust appears at a scratch, or the head seizes to the part. |
| Why it happens | The grade is not suitable for chlorides, and the joint is left wet. |
| What we control | Grade confirmed on the certificate; first article exposed and inspected. |
| Where it sits | The fastener holds guards that are removed and refitted during maintenance. |
| When it goes wrong | The heads round, or the joint loosens between services. |
| Why it happens | A wrench cannot swing in the space, and the service uses the wrong tool. |
| What we control | Clearance around the head checked; first article fitted with the guard. |
Four reasons that matter on a fastener whose drive sits outside the head, each tied to something the drawing or the first article proves. All four show in the sample.
|
Head and clearance stated
The drawing states the head across flats and the clearance around it, because a hex head needs room for the socket to turn. Basis: Head and clearance agreed. |
Head and thread as one part
The head is formed and the thread produced to the drawing, so the bearing face runs square to the thread rather than being corrected later. Basis: Head square to thread. |
|
Joint assembled and loaded
The first article is assembled with the mating nut and checked after loading, because the clamp is developed across the joint. Basis: Joint proved under load. |
Same grade and limits
Grade, head and thread are recorded with the drawing revision, so a repeat batch tightens the same way. Basis: Same limits across orders. |
These fasteners are formed and turned from stainless bar and wire, with the hexagon head formed, the bearing face machined and the thread cut; the parts are cleaned, passivated and inspected. The first piece of every run is measured on head across flats and height, bearing face flatness, thread and length.
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The head is formed to its across-flats and then the bearing face is machined square to the thread. On a hex head that face carries the clamp, so a face that is out of square loads one side of the joint and can bend a thin bracket.
The thread is produced after the head, so the part can be held by the head and the thread stays concentric with the flats. Cutting rather than rolling keeps the crest clean on stainless, which matters where a nut has to run a distance to seat.
Passivation comes last. Every batch is checked for across-flats and thread, and a sample is assembled with a nut and loaded to confirm the joint holds its clamp.
What decides whether stainless steel fasteners pass is the head, the bearing face and the thread. The inspection agreement covers those, and the criteria come from the drawing.
Head and thread on the projector |
Thread and start checked |
Material checked |
Salt-spray testing where a coating is used |
On these stainless steel fasteners the head is measured across flats and for height, and the corners are checked for a burr. A burr at a corner stops the socket seating fully, and the wrench then rounds the head instead of turning the fastener.
The bearing face is checked for flatness and squareness to the thread. That face is what carries the clamp, so a face that is dished or bent is a joint that loosens under load rather than a cosmetic defect.
The thread is gauged, and a sample is assembled with a nut of the specified grade and loaded. That test shows whether the stainless joint reaches and holds its clamp without galling.
Every batch of stainless steel fasteners is traceable to the bar or wire it was made from and to the passivation lot that finished it. The grade and heat number appear on the material certificate supplied with the parts, and the dimensional results are recorded against the drawing revision.
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 and thread, and the passivation record. The records carry the drawing revision and the batch number, so a repeat order of stainless steel fasteners tightens 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 structural fastener the first article is assembled with the mating nut and checked under load. Buyers visit during the process to review samples.
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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
|
Repeat orders of stainless steel fasteners are made from the same grade, because a substitute changes both the corrosion behaviour and the seizing, and the head has to keep working through the assembly. Buyers and quality engineers visit for sample review, process discussion and supplier audits; the visit is arranged around production so the machining cell and the inspection bench 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 wrench on the outside can apply more torque and does not need a recess in the head. The trade is the clearance the wrench needs.
Enough for the socket plus a swing radius. On a dense assembly this is often the dimension that decides the fastener.
Driven from a hexagon head into a nut, it is usually called a bolt; driven into a tapped hole, a screw. The clamp path differs.
It carries the clamp. A dished or bent face loads one side and loosens the joint under load.
A coating would change the across-flats and the bearing face. Plain stainless keeps both as machined.
They can. A lubricant may be needed so the joint reaches its clamp instead of galling.
How a stainless steel fastener project runs from drawing to repeat delivery:
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1
Send the drawing and the joint
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→ |
2
Head, thread and clearance agreed
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→ |
3
First article assembled and loaded
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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 across flats and height, thread size and length, grade and finish, the mating nut or tapped hole, and the clearance around the head.
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Head AF
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Head height
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Thread
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Length
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Grade
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Clearance
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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
