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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:Double End Stud Bolt Machine Screw
Materials:Steel
Surface treatment:White Zinc Plated
Head Type:Stud Head
Drive:None (double end stud)
Thread:Machine thread, both ends
Point:Chamfered both ends
Forming:Thread rolled on bar
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M14
Number:841
We make double end stud bolts in white zinc plated carbon steel, threaded at both ends with a plain middle, quoting them from M1 to M14. Setting length, nut length, middle diameter, thread class and coating come from your drawing, and the first article is set into your tapped part.
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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 double end stud bolt is a headless fastener threaded at both ends with a plain section between them, made here in carbon steel with a white zinc finish and quoted from M1 to M14 with Number 841. One end is set into a tapped hole and stays there; the other end takes a nut; the plain middle takes the load and keeps the two parts in line.
No head. There is nothing to turn, so a double end stud bolt is installed with a stud driver or by locking two nuts on the free end.
Two threaded ends. The setting end goes into the parent part, the nut end takes the fastener; their lengths are usually different and both belong on the drawing.
Plain middle. An unthreaded section whose diameter and length set the fit between the parts and the distance they stand apart.
White zinc plated steel. A bright sacrificial coating over carbon steel, applied after the threads are rolled and gauged again afterwards.
On a double end stud bolt the two ends do different jobs, and the drawing should treat them separately. The setting end is screwed into the parent part and usually stays there for the life of the assembly; it needs enough engaged thread to reach the full strength of the joint, and in a blind hole it needs to stop before it bottoms. The nut end is the working end: it is tightened, released and re-tightened, so its thread length is set by the nut plus a few spare threads – and by how much stud should stand proud of the nut.
Setting depth is the number that goes wrong. A setting end that is too long bottoms in a blind hole and leaves the stud standing off, so the nut never clamps the part; one that is too short leaves only a few threads engaged and pulls out under load. Both failures look identical from outside the assembly, which is why the setting length is specified to the depth of the tapped hole rather than to a fraction of the diameter.
The plain middle is a locating feature, not just a gap. In an assembly where two parts have to line up – a flange on a housing, a cover over a bore – the plain section runs in the clearance hole of the second part and holds it concentric while the nut is tightened. If the thread is carried through that section, the thread edges cut the bore and the two parts settle off-centre.
Installation is where the absence of a head matters. The usual method is to lock two nuts on the nut end and turn the lower one, which drives the stud by its thread rather than by a drive feature; the alternative is a stud driver that grips the plain section. Neither method allows much torque, so the setting torque is limited by the thread in the parent part, and that part is usually the softer of the two.
White zinc plating adds a few microns to both threads, and the setting end is the one that notices. It runs into a tapped hole with a fixed clearance, so a plated stud that was gauged before plating can bind on the way in and read as a bad thread when the thread is fine. Plating and gauging order belongs in the process note.
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 double end stud bolt the quotation carries the setting length, the nut length, the overall length and the plain middle diameter, because those four numbers decide whether the stud sets, clamps and aligns.
| Item | How it is defined | What we control |
|---|---|---|
| Head | None, double end | End chamfers and squareness of the ends |
| Setting end | Thread into the parent part | Thread length and end chamfer |
| Nut end | Thread for the nut | Thread length and thread stop |
| Middle | Plain section between the threads | Diameter, length and concentricity |
| Thread | Machine thread, both ends | Pitch, class and gauging after plating |
| Material | Carbon steel | Grade and heat number on the certificate |
| Finish | White zinc plated | Coating thickness and appearance |
End lengths should be dimensioned from the ends, not from each other. A drawing that gives overall length and one thread length leaves the other end to arithmetic, and the arithmetic is done differently by every shop that quotes it.
The plain middle diameter is worth a tolerance of its own. Where it runs in a clearance hole it is a fit, and where it simply spaces two parts it is a distance; the two uses ask for different precision on the same section.
Three features define the part: the absence of a head, the two threaded ends and the plain middle. The first makes it a permanent connection on one side and a serviceable one on the other, the second gives each end its own length and engagement, and the third is the alignment.
| Feature | What it gives | What it costs |
|---|---|---|
| No head | Nothing protruding on the setting side | No drive; installed with nuts or a stud driver |
| Two thread lengths | Each end matched to its job | Both must be dimensioned |
| Plain middle | Locates the second part | Must be true and sized to the hole |
| White zinc | Bright, sacrificial protection | Build on both threads |
| Carbon steel body | Strength at low cost | Needs the coating for corrosion |
The headless form is the reason the part exists in pump bodies, housings and castings. The parent part is tapped once, the stud stays in it, and the cover or flange is removed and refitted against the same studs, which keeps the alignment and spares the casting’s thread from repeated use.
That also means the stud is only as good as the tapped hole. A casting thread that is worn or galled will not hold the setting torque, and no amount of stud quality recovers it; the fit is a property of the pair.
The recorded finish is white zinc plating over carbon steel, the bright blue-white deposit that is standard on general-purpose steel fasteners. It is sacrificial, so a scratch in the coating still leaves the steel protected nearby, and it is thin enough to keep a fine thread usable – provided the parts are gauged after plating rather than before.
| Option | How it protects | Effect on the two threads | Typical use |
|---|---|---|---|
| White zinc plated | Sacrificial zinc, bright | Build re-gauged on both ends | General machinery and castings |
| Black oxide | Conversion film, oiled | No measurable build | Internal machine assemblies |
| Zinc nickel | Alloy coating, higher salt resistance | Noticeable build; both ends gauged | Automotive and outdoor |
| Dacromet | Inorganic zinc-aluminium layer | Build allowed for at the thread | Wet and marine assemblies |
| Stainless, passivated | Passive film | None; threads as cut | Food, marine and chemical |
Where the joint works in wet or coastal air, a coated steel stud is a shorter-lived choice than a stainless one, and the difference shows at the setting end first because it is the thread that never gets inspected. For washdown and marine service the stainless grade is the specification that removes the question.
Where the stud is set into a casting and left for years, the coating also decides whether it can be removed. Zinc on zinc can seize in a tapped hole; a thread lubricant at setting, specified in the assembly note, is what keeps the option of removal open.
Three assemblies where a double end stud bolt is the fixing:
| Where it sits | The stud stays in the cast body and the flange or cover is drawn down on it with nuts, so the casting thread is used once and the joint can be reopened. |
| When it goes wrong | A setting end that bottoms in a blind hole leaves the cover standing off, and the joint leaks. |
| Why it happens | The parent part is cast, the joint is reopened, and alignment is carried by the studs. |
| What we control | Setting length checked against the tapped depth, coated threads gauged. |
| Where it sits | The stud locates a bearing cover or an end plate while the nut clamps it, keeping the plate concentric with the bore. |
| When it goes wrong | A threaded middle cuts the clearance hole and the plate settles off-centre. |
| Why it happens | The joint is a fit, it is machined, and the plate must sit true. |
| What we control | Plain middle diameter toleranced, concentricity checked on the projector. |
| Where it sits | The stud joins two flanges with nuts on the free end, allowing the joint to be broken and remade without disturbing the stud in the lower flange. |
| When it goes wrong | A nut end that is too short leaves too few threads for the nut, and the joint cannot be fully tightened. |
| Why it happens | The joint is pressure-tight, it is serviced, and the studs stay in place. |
| What we control | Nut length set to the nut plus thread allowance; both ends gauged. |
Four reasons that matter on a headless stud, each tied to what the drawing has to prove:
|
Both end lengths agreed
The setting length and the nut length are dimensioned from their own ends, because a double end stud bolt is installed by one end and tightened by the other. Basis: Both end lengths dimensioned. |
Rolled, cut, plated in one route
Both threads are rolled on the same bar, the ends are chamfered and the parts are plated and re-gauged in one route. Basis: One route from bar to plated stud. |
|
Threads gauged after plating
Both threads are gauged after plating, because the deposit is what a setting end feels in a tapped hole. Basis: Both threads gauged after plating. |
Middle diameter held to the fit
The plain middle is measured to its own tolerance, because on a double end stud bolt that section is the alignment. Basis: Middle section measured to fit. |
Shi Shi Tong makes double end stud bolts from carbon steel bar, cutting the blanks to length, rolling the thread at both ends, chamfering the ends and white zinc plating the finished parts. The plain middle is left unthreaded at the diameter the drawing calls for, and both threads are gauged after plating before the batch continues.
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Rolling two threads on one bar is where the part is decided. The thread rolls have to stop at the same place every time, because the length of plain section between them is the alignment feature; a roll that creeps leaves one end long and the other short, and the stud still measures to overall length while fitting nothing.
What decides whether double end stud bolts pass is the two thread lengths, the middle diameter, the thread class and the coating. The inspection agreement covers those, and the criteria come from the drawing.
Ends and middle on the projector |
Both threads gauged per batch |
Hardness checked on the bar |
Coating proved by salt spray |
Every stud is checked for overall length and for both thread lengths from their own ends, and the middle diameter is measured over the plain section. Both threads are gauged after plating, and the coating is checked for thickness and appearance against the approved sample.
Where the stud is set into a blind hole, the first article is set into the customer’s tapped part and the stand-off is measured. That is the check that catches a bottoming setting end, and a bench measurement cannot make it.
Every shipment of double end stud bolts is traceable to the bar 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 coating. The documents carry the drawing revision and the batch number, so a repeat order is made to the same two thread lengths that were 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 double end stud bolt the first article is set into the customer’s tapped part, because the setting depth is a property of the pair. Buyers visit during the process to review samples and to see how the threads are rolled.
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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 thread rolls 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 |
One end sets into the parent part and stays; the other takes the nut and is worked. Each length is set by its own job, so both are dimensioned.
With a stud driver on the plain middle, or by locking two nuts on the free end and turning the lower one.
The stud stands off and the nut never clamps the part. The setting length is checked against the tapped depth on the first article.
It locates the second part in its clearance hole. A thread carried through that section cuts the bore and the part settles off-centre.
Yes. The deposit adds to both threads, so the setting end is gauged after plating rather than before.
Overall length, setting length, nut length, middle diameter and tolerance, thread class, the material and the coating.
How a double end stud bolt project runs from drawing to repeat delivery:
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1
Send the drawing and the tapped hole depth
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→ |
2
Setting length, nut length and middle agreed
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→ |
3
First article set into your tapped part
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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 length, setting length, nut length, middle diameter and tolerance, thread class, the material and the coating.
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Overall length
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Setting length
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Nut length
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Middle diameter
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Thread class
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Coating
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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
