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:Non Standard Socket Screw
Materials:Steel
Surface treatment:Black Zinc Plated
Head Type:Cap Head
Drive:Allen Socket
Thread:Partial Machine Thread
Point:Blunt
Forming:Single Die Heading + Turned Shank
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:262
We make non standard socket screws to drawing in black zinc plated carbon steel, with a cup head, a hexagon socket, a partly threaded shank and a defined undercut, quoted from M1 to M14. Shank tolerance, thread length and undercut come from your drawing, and the first article is fitted to your own component.
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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.
A non standard socket screw is a hexagon socket screw made to a drawing rather than to a catalogue part number. The thread, the drive and the material may all be ordinary; what is not ordinary is some dimension of the head, the shank or the thread length that no standard covers. On the recorded item the part is carbon steel with a black zinc plate, a cup head, a hexagon socket and a partly threaded shank, quoted from M1 to M14 with Number 262.
Cup head. A cylindrical head with a flat top face and a hexagon socket cut into it, seating on a flat face or in a counterbore.
Partly threaded shank. A defined plain length below the head and a threaded length below that, so the plain shank can act as a locating diameter.
Machine thread. A rolled thread for a tapped hole or a nut.
Black zinc. A dark sacrificial zinc deposit, applied over the finished part.
Every non standard socket screw is a small set of decisions that a catalogue part made for you. Which diameter is the plain shank; where the thread stops; whether there is an undercut at the transition; how deep the socket goes; how much of the head is chamfered. Each is easy to draw and each has a manufacturing consequence, whether or not the drawing says so.
The partial thread is usually the decision that matters most. A plain shank below the head can act as a locating diameter, a bearing surface for a sliding component or a stop against a shoulder, and its tolerance is different from the thread’s: the thread only has to fit, the shank often has to fit and be concentric. That is where a non standard socket screw earns its place — the shank does a job a thread cannot.
The transition between the shank and the thread is the second decision. A thread that simply fades into the shank leaves a ragged end and a stress step; a defined undercut gives the die somewhere to finish. Where the shank is a locating diameter that has to reach a shoulder, the undercut is not optional, because without it the thread runs into the feature it was supposed to stop short of.
The head is the third. A cup head can be given a smaller diameter, a lower height, a deeper socket or a chamfer on the top edge, and each costs a different amount. A head that is standard except for one bump usually needs no new tooling; a head that is a different form entirely may need a new die, and that changes the economics from a batch to a programme.
That is how a custom job stays economical: keep the thread and the drive standard, and put the non-standard feature where it can be produced by a second operation — turning, grinding, milling or drilling after the part is formed. A part that is standard in its wire, its die and its thread and non-standard only in a turned step is a very different proposition from one that needs a new heading die.
The recorded range is M1 to M14, covering M1, M2, M3, M4, M5, M6, M7, M8, M9, M10 and M14. Custom lengths up to 2,000 mm are subject to DFM review after drawing submission. For a non standard socket screw the drawing has to state the overall length, the threaded length, the shank diameter and its tolerance, and the socket size and depth.
| Item | How it is defined | What we control |
|---|---|---|
| Head | Cup head, flat face | Diameter, height, chamfer |
| Socket | Internal hexagon | Socket across flats and depth |
| Shank | Plain, locating diameter | Diameter and tolerance, concentricity |
| Thread | Partial machine thread | Threaded length and position |
| Transition | Undercut at the thread end | Groove diameter and position |
| Finish | Black zinc | Deposit thickness and adhesion |
The threaded length is worth calling out separately from the overall length. A drawing that gives only an overall length leaves the split between shank and thread to the maker, and two batches can then be legitimate and different. On a non standard socket screw the threaded length is a functional dimension whenever the shank locates something.
The same applies to the shank tolerance. A shank quoted as a nominal diameter with no tolerance will be made to a general one, and a component that slides on it will fit some parts and not others. Where the shank is a fit, the tolerance belongs on the drawing in the same way a bore tolerance would.
Three features define this part: the cup head with its socket, the partly threaded shank and the coating. The first is the drive, the second is the custom geometry that made the part necessary, and the third is the protection.
| Feature | What it gives | What it costs |
|---|---|---|
| Cup head with socket | High torque in a compact head | Needs a counterbore or a flat seat |
| Plain shank | Locating fit, bearing surface | Shank tolerance must be specified |
| Partial thread | Thread where it is needed | Thread length is a functional dimension |
| Undercut | Clean thread end, defined shoulder | An extra turning operation |
| Black zinc | Dark, sacrificial protection | Thin; scrapes at the socket |
The plain shank is the feature most often asked for and most often under-specified. It is a locating diameter, and a locating diameter that is 0.05 mm oversize does not locate; it jams. Before the drawing is released it is worth writing down what the shank has to do — slide, centre, bear or stop — because each of those asks for a different tolerance band.
Customising also has a cost curve. Changing a turned dimension after heading is inexpensive; changing a heading die is not; changing the socket size changes the punch and the head height. A non standard socket screw that stays inside those limits is a normal production part; one that does not becomes tooling work.
The recorded finish is black zinc, applied to the finished part. On a custom geometry the coating is the last operation, so the threads, the shank and any undercut are plated after they are made; a shank tolerance that was specified without allowing for the deposit can end up undersize or tight depending on the fit.
| Option | How it protects | Effect on geometry | Typical use |
|---|---|---|---|
| Black zinc | Sacrificial zinc, dark | A few microns; shank fit re-checked | Dark machine assemblies |
| White zinc | Sacrificial zinc, trivalent | A few microns; shank fit re-checked | Indoor, RoHS-driven work |
| Nickel plated | Barrier deposit, bright | Decorative; thin | Visible custom fixings |
| Black oxide | Conversion film, oiled | No measurable build | Internal machine parts |
| Stainless, plain | Passive chromium oxide film | None; gauged as cut | Wet or outdoor machines |
For a part with a locating shank the coating is not a detail. A plated shank is a few microns large, and if the fit was specified on the bare dimension the assembly will be tight. The practical answer is to state the tolerance on the plated part and let the process work back from there.
Three assemblies where a non standard socket screw is the fixing:
| Where it sits | The screw locates a jaw, a stop or a plate on a plain shank and clamps it with a thread below, where a standard screw cannot give both functions. |
| When it goes wrong | A shank made to a general tolerance will not locate, and the fixture loses its setting. |
| Why it happens | The shank is a fit, the head is buried, and the joint is adjusted. |
| What we control | Shank diameter and tolerance checked, socket driven with the production key. |
| Where it sits | The screw acts as a shoulder pin for a link or a roller, with the thread taking the preload and the plain length taking the load. |
| When it goes wrong | A thread that runs into the shank wears the component it was meant to locate, and an undercut in the wrong place leaves no shoulder. |
| Why it happens | The plain length carries a load, the thread only clamps, and the joint moves. |
| What we control | Thread length and undercut position checked, shank measured on the projector. |
| Where it sits | The screw replaces an obsolete fixing on a machine that is being rebuilt, where the drawing comes from the part rather than from a standard. |
| When it goes wrong | A dimension taken from a worn sample propagates the wear, and a missing tolerance is filled in by habit. |
| Why it happens | The part is obsolete, the sample is worn, and the drawing is new. |
| What we control | Dimensions reviewed against function, tolerances agreed before production. |
Four reasons that matter on a made-to-drawing socket screw, each tied to what the drawing has to prove:
|
Function reviewed before tolerances
The shank, the thread length and the undercut are reviewed against what each has to do, because a non standard part fails on the dimension nobody specified rather than on the one that was. Basis: Each custom feature reviewed against its function. |
Heading plus second operations
The head and socket are formed in the heading stroke and the custom features are turned, milled or ground afterwards, so the thread and drive stay standard. Basis: Standard process, custom second operations. |
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First article measured on the shank
The first article is measured on the shank and the thread, driven with the production key and fitted to the customer component, because the fit is the function. Basis: First article fitted to the component. |
First article fixes the setting
The first article fixes the wire, the die and the second operations; repeat orders are compared against that record. Basis: First article signed off before the batch is released. |
Shi Shi Tong forms these non standard socket screws from carbon steel wire on single-die headers that form the cup head and the hexagon in one stroke, rolls the machine thread, turns the plain shank and any undercut, and plates the finished part in black zinc. The first part of every run is measured on the head, the shank and the thread and driven with the production key before the batch continues.
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The second operation is where a custom part lives or dies. Turning a shank after heading means holding the part on the thread or the head and cutting a diameter that has to be concentric with both; the set-up is checked on the first part of the run and then held, because a small drift in the chuck shows up as a shank that is round but not concentric.
What decides whether non standard socket screws pass is the shank, the thread, the head and the coating. The inspection agreement covers those, and the criteria come from the drawing.
Shank and undercut on the projector |
Thread gauged per batch |
Hardness checked on the wire |
Salt-spray testing of the plate |
The shank is measured for diameter and, where it locates, for concentricity with the thread. Both matter and only the first is usually on the drawing: a shank that is round and to size but eccentric turns a component that should slide into one that binds at one point of rotation.
The thread is gauged per batch, the threaded length is checked against the drawing rather than against the overall length, and the undercut is checked for position and depth. The coating is checked after plating, because the shank that passes on a bare part can fail its fit once it is a few microns larger.
Every shipment of non standard socket 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, 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 plating. The documents carry the drawing revision and the batch number, so a repeat order is made to the same revision that was approved.
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 non standard part the first article is fitted to the customer’s component, because the custom feature is the function. Buyers visit during the process to review samples and to see how the parts are formed and finished.
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8,678+
customers served
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87%
of orders from repeat customers
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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 second-operation cells 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 |
Any feature with no catalogue equivalent: a shank diameter, a thread length, an undercut, a head dimension or a drive size that the standards do not fix.
Give it as its own dimension, not as a difference from the overall length. The split between shank and thread is functional whenever the shank locates something.
It depends on what the shank does. Sliding, centring, bearing and stopping all want different bands, and a general tolerance will not do for a fit.
Where the thread has to finish cleanly short of a shoulder, yes. Without it the thread reaches into the feature it was supposed to stop short of.
Yes, but the coating changes the shank and the socket. Specify tolerances on the plated part and let the process work back from there.
Overall length, threaded length, shank diameter and tolerance, undercut position, head diameter and height, socket size and depth, material and finish.
How a non standard socket screw project runs from drawing to repeat delivery:
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1
Send the drawing and the component it fits
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→ |
2
Each custom feature reviewed against its function
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→ |
3
First article fitted to your component
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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 overall and threaded lengths, the shank diameter and tolerance, the undercut, the head and socket dimensions, and the material and finish.
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Overall length
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Thread length
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Shank diameter
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Undercut
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Socket size
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Finish
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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
