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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 Threaded Stud Screw Bolt
Materials:Stainless Steel
Surface treatment:Plain
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:842
We make double end threaded studs in passivated A2 stainless, threaded at both ends with a plain middle, quoting them from M1 to M14. Grade, setting length, nut length, middle diameter and thread class come from your drawing, and the first article is set into your 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 threaded stud is a headless bar threaded at both ends with a plain section in between, made here in stainless steel with a plain passivated finish and quoted from M1 to M14 with Number 842. One end is set into a tapped hole, the other takes a nut, and the unthreaded middle spaces and locates the two parts.
Stainless body. A2 grade as standard, passivated and uncoated, so both threads and the plain middle are exactly as made.
Two threaded ends. The setting end goes into the parent part and the nut end takes the fastener; their lengths are dimensioned separately.
Plain middle. An unthreaded section that runs in the clearance hole of the second part and holds it concentric while the nut is tightened.
No head. Nothing to drive, so the stud is installed with a stud driver on the plain section or by locking two nuts on the free end.
A stainless double end threaded stud looks like the zinc plated version and behaves differently in two places: the thread that has to be screwed in, and the plain section that sits in the mating part. Both differences come from the alloy rather than from the geometry, and both are decided during assembly rather than at the drawing stage.
The first is galling. Stainless on stainless has no coating to act as a soft layer between the threads, and under pressure the two surfaces weld at spots and tear. A setting end driven into a stainless parent part can seize part way in, and it gives no warning: the torque does not rise, it simply stops turning. The usual controls are a molybdenum-based anti-seize on the setting thread and a pair of grades that do not match, such as an A2 stud in an A4 part.
The second is galvanic coupling. A stainless stud in an aluminium or magnesium housing makes a couple in the presence of moisture, and the aluminium around the thread corrodes preferentially. The stud itself stays bright while the hole it sits in opens up, so the fault is invisible until the joint loosens. Isolation washers or a sealant at the setting end are the practical answers, and they belong in the assembly note rather than in the stud drawing.
Passivation is the third difference, and it is in the stud’s favour. There is no plating build on either thread, so a stainless stud sets to the same fit every batch, and the thread a customer gauges at the hole is the thread they receive. On a zinc plated stud the plating thickness is a variable; here it is zero.
The plain middle does the same job in both materials, but it matters more in stainless because the part is usually chosen for a wet or hygienic environment where bores are machined to fine fits. A threaded middle would cut that bore; a plain section, sized to it, is what keeps two machined parts concentric while the nut draws them together.
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 threaded stud the quotation carries the setting length, the nut length, the overall length, the plain middle diameter and the grade, because those decide the fit at both ends and the alignment in between.
| Item | How it is defined | What we control |
|---|---|---|
| Head | None, double end | End chamfers and squareness |
| 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 | Diameter, length and concentricity |
| Thread | Machine thread, both ends | Pitch, class and gauging |
| Material | A2 stainless steel | Grade and heat number on the certificate |
| Finish | Passivated | Surface condition and film |
Grade belongs on the drawing with the finish, not separately. An A2 stud passivated is the general answer; an A4 stud is the one for chlorides, and on a stud that lives inside a marine or washdown assembly the grade is what decides the service life.
The middle diameter should carry its own tolerance where it is a fit. Two parts machined to a bore and then located on a stud need the plain section within a few hundredths, and that is a different number from the overall length tolerance beside it.
Three features define the part: the stainless body, the two threaded ends and the plain middle. The first removes the plating from the thread fit and brings galling into the assembly plan, the second gives each end its own length, and the third is what keeps the two parts coaxial.
| Feature | What it gives | What it costs |
|---|---|---|
| Stainless body | Corrosion resistance, no coating wear | Galls dry against stainless |
| No head | Nothing protruding on the setting side | Installed with nuts or a stud driver |
| Two thread lengths | Each end matched to its job | Both dimensioned separately |
| Plain middle | Locates the second part | Sized and toleranced as a fit |
| Passivated finish | Threads exactly as cut | Not a lubricant |
The absence of a coating is a real advantage on the thread. On a plated stud the setting end gains a few microns and can bind in a tapped hole that was cut to the bare thread; a stainless stud has no such step, so the thread the customer’s gauge accepts is the thread that goes in.
The cost is galling, and it is paid at installation. A stainless stud set into a stainless casting with no lubricant can seize at the first attempt, and a stud that has seized is not coming out without damage to both threads.
The recorded finish is passivation with no coating on A2 stainless. On a stud this is the right finish for two reasons: the threads are the functional surface and a coating would change both of them, and the part is usually chosen for a wet or hygienic location where the protection has to survive being scratched rather than being intact.
| Option | How it protects | Effect on the threads and middle | Typical use |
|---|---|---|---|
| A2 stainless, passivated | Passive chromium oxide film | Both threads exactly as cut | General machinery and food equipment |
| A4 stainless, passivated | Passive film with molybdenum | Both threads exactly as cut | Marine and chemical service |
| Carbon steel, white zinc | Sacrificial zinc | Build on both threads; re-gauged | Dry indoor assemblies |
| Carbon steel, Dacromet | Inorganic zinc-aluminium layer | Build allowed at the thread | Wet outdoor hardware |
| Brass, plain | No protection needed indoors | Soft thread; sets easily | Electrical and decorative |
A2 against A4 is the choice that decides corrosion life. A2 covers ordinary indoor and outdoor exposure; A4 is the grade where chlorides are present, which for a stud means a marine fitting, a washdown line or a chemical plant.
Where the stud goes into an aluminium or magnesium part, the material choice is a galvanic question rather than a corrosion one, and an isolating washer or a sealant at the setting end is part of the specification. That note belongs on the assembly drawing, because the stud itself cannot solve it.
Three assemblies where a double end threaded stud is the fixing:
| Where it sits | The stud stays in a stainless housing and a cover or a clamp plate is drawn down on it with a nut, so the thread in the housing is used once. |
| When it goes wrong | Seizing at the setting end means the stud cannot be replaced without damaging the housing thread. |
| Why it happens | The joint is washed daily, the parts are stainless, and it is serviced. |
| What we control | Grade confirmed, setting thread anti-seize specified, both threads gauged. |
| Where it sits | The stud joins a fitting to a structure with nuts at the free end where the joint has to be opened for maintenance. |
| When it goes wrong | A2 in salt air pits at the setting end, and the stud breaks inside the parent part. |
| Why it happens | The joint is exposed, it is wet, and it is maintained. |
| What we control | A4 confirmed on the certificate, coating-free threads checked. |
| Where it sits | The stud locates a plate inside a stainless instrument where the parts are cleaned and must be non-magnetic. |
| When it goes wrong | Galling at assembly contaminates the thread, and a seized stud blocks a service procedure. |
| Why it happens | The joint is cleaned, inspected and disassembled for service. |
| What we control | Passivation record with the batch, setting thread lubricant specified. |
Four reasons that matter on a stainless stud, each tied to what the drawing has to prove:
|
Grade and both ends agreed
The grade, both thread lengths and the middle diameter are settled before production, because the grade decides the corrosion life and the middle decides the fit. Basis: Grade and both ends agreed. |
Rolled, passed and gauged in one route
Both threads are rolled on the same bar, the ends are chamfered and the parts are passivated and gauged in one route. Basis: One route from bar to passivated stud. |
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Both threads gauged on the part
Both ends are gauged on the finished part, because a stainless stud has no plating to mask or correct a thread. Basis: Both threads gauged on the part. |
Setting length fixed by the first article
The first article is set into the customer part, so the setting length is proved in the hole it lives in, not on the bench. Basis: First article set in the customer part. |
Shi Shi Tong makes double end threaded studs from stainless bar, cutting blanks to length, rolling the thread at both ends, chamfering the ends and passivating the finished parts. The plain middle is left unthreaded at the diameter the drawing calls for, and both threads are gauged on the finished part before the batch continues.
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Rolling stainless is harder on tooling than rolling steel. The material work-hardens as it is formed, so the rolls have to be set to form the thread in one pass and then leave it alone; a roll that slips and re-forms the same thread will crack the crests, and the crack shows up as a rough thread rather than as a failure until the stud is loaded.
What decides whether double end threaded studs pass is the two thread lengths, the middle diameter, the thread class and the grade. The inspection agreement covers those, and the criteria come from the drawing.
Ends and middle on the projector |
Both threads gauged |
Hardness checked on the bar |
Salt-spray testing of the grade |
Both ends are measured for thread length from their own ends, the middle for diameter and for concentricity with the threads, and the thread is gauged at both ends. The grade is confirmed on the mill certificate rather than by appearance, because A2 and A4 look the same.
A salt-spray sample is run where the environment asks for it, and the setting end is the part of the sample that matters: it is the thread that sits in the parent part and is never seen again.
Every shipment of double end threaded studs is traceable to the bar it was made from and to the passivation 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 grade or the passivation. The documents carry the drawing revision and the batch number, so a repeat order is made to the same grade and 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 threaded stud the first article is set into the customer part and checked for setting depth and thread engagement. 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 passivation 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 |
Stainless on stainless galls under pressure with no coating in between. A molybdenum anti-seize on the setting thread, or a pair of different grades, is the control.
The middle is the same alloy as the threads. What matters is that it is sized to the bore it locates, whichever grade is used.
A coating would change both thread fits. Passivation leaves the threads exactly as rolled, so the fit at the setting end is predictable.
There is a galvanic couple in moisture, and the aluminium corrodes around the thread. An isolating washer or a sealant at the setting end is the usual answer.
A stud driver on the plain middle, or two nuts locked on the free end with the lower one turned.
Overall length, setting length, nut length, middle diameter and tolerance, thread class, the grade and the passivation.
How a double end threaded stud project runs from drawing to repeat delivery:
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1
Send the drawing and the parts it joins
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→ |
2
Grade, both ends and middle agreed
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→ |
3
First article set into your 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 grade and the finish.
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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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Grade
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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
