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:Custom Long Screws
Materials:Stainless Steel
Surface treatment:Plain
Head Type:Hexagon head
Drive:External hex (wrench or socket)
Thread:Machine thread, coverage per drawing
Point:Plain, chamfered
Forming:Turned or formed; thread produced at the end
Size:M1 M2 M3 M4 M5 M6 M7 M8 M9 M10
We make custom long screws in stainless steel to a stated length and thread coverage, with a drawing review before production. Beyond the standard range the limits are material, machine length, packing and assembly alignment, so length, thread and the holes it crosses are agreed first.
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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.
Custom long screws are screws made to a length outside the standard range, with the thread coverage, head form and finish set by the drawing. The part recorded here is stainless steel left plain, with a hexagon head, quoted with the length made to order and reviewed against the drawing before production.
Made to a length. The length is a drawing dimension rather than a stock size, and it is checked as such.
Defined thread coverage. How much of the body carries thread is stated, because on a long part that decides how it is used.
Hexagon head. A drive that stays on the axis and takes torque without a recess to wear.
They are used where the reach is the function: frames, stands, tie rods and long-reach adjusters that no stock length covers. In that sense a custom long screw is a small engineering item rather than a catalogue part, and the review before production is aimed at the length rather than the thread.
A screw can be made longer than standard stock, but at some length the constraints stop being about the thread and start being about everything around it. The first is material: the bar or wire has to exist in the grade and diameter, and a long part uses more of it than a short one. The second is the machine: turning and threading need the length between centres, and handling a long part between operations is a different activity from handling a short one.
The third constraint is packing and transport. A long screw that is packed like a short one arrives bent, and a bent long screw cannot be straightened on an assembly line. That is why long parts are packed in supports that hold them along the length, and why the packing is agreed with the drawing rather than left to the shipping department.
The fourth is assembly. On a very long part the key or the driver acts at one end of a long lever, and a small misalignment becomes a side load against every hole the screw passes. The result is a thread that starts badly at the far end, which is the most common failure of a long part and the least visible before assembly.
Those four constraints are what a quotation for custom long screws is really assessing. The thread, the head and the material are ordinary; the length is what makes the part a project, and the review is about whether the length can be made, packed, shipped and assembled as drawn.
On the drawing, that means the length is stated under the head, the thread coverage is stated separately, and the holes the screw passes through are noted. With those three numbers a long screw can be quoted and checked; without them, the part is a guess at both ends.
The part is quoted to the drawing with the length, the thread coverage and the head stated separately. Custom lengths up to 2,000 mm, subject to DFM review after drawing submission. The quotation carries the length under the head, the threaded length, the head and drive, the finish, and the parts the screw passes through.
| Item | How it is defined | What we control |
|---|---|---|
| Length | Under the head | Length and cut end |
| Thread coverage | How much of the body | Threaded length and start |
| Head | Hexagon or socket | Diameter, height and drive |
| Body | Plain where unthreaded | Diameter and finish |
| Packing | For a long part | Support along the length |
| Pass-through | Customer parts | Hole sizes agreed |
On custom long screws the length is measured from the bearing face to the end and checked with a length gauge on a sample from each batch. On a long part it is a distance rather than a feature, so it is recorded as a number and compared with the drawing rather than with a comparator.
Thread coverage is a drawing decision, not a workshop one. Full thread gives an adjustable nut position; partial thread gives a clean pass-through body. Both are legitimate long parts and they are not interchangeable.
The head is standard in form, but its height still matters because it is what the counterbore in the customer part has to clear. A head turned shorter to save material changes the pocket depth the customer needs.
Four properties decide custom long screws, and each one carries a cost:
| Property | What it gives | What it costs |
|---|---|---|
| Made-to-length | Reach that stock cannot give | A drawing review before production |
| Defined thread | The engagement the joint needs | Two dimensions to check, not one |
| Hexagon head | On-axis drive, no recess to wear | Needs clearance for a wrench |
| Long packing | A part that arrives as made | Volume and handling cost |
For custom long screws the value is that the joint can be made at all. Where a frame is deep or an adjustment is long, no stock screw reaches, and a made-to-length part is the only way to keep the joint to a single thread pair.
The cost is that the part is a small project rather than a catalogue item: the drawing has to define the length and the thread, and the packing has to keep it straight enough to use.
The recorded finish is plain stainless steel. On a long part that gives a body that does not rust where it is handled and a thread that is bare metal where it engages, and it avoids a coating that could be rubbed off along a long length during packing and transport.
| Option | How it protects | Effect on body and thread | Typical use |
|---|---|---|---|
| Plain, passivated | Passive film, no coating | Body and thread as made | Stainless assemblies |
| Passivated 316 | Higher alloy passive layer | No build; better in chlorides | Marine and outdoor |
| Nickel plated | Hard bright barrier | Thin build; thread re-gauged | Visible long fixings |
| Zinc plated | Sacrificial zinc | Build on thread; gauged after | Cost-driven dry work |
| Black oxide | Conversion film, oiled | No measurable build | Dark mechanisms |
On a long part, finish uniformity is a visible property. A body that is bright in the middle and dull at the ends reads as two different batches, which is why coverage along the whole length is checked rather than only at the ends.
A coated thread is gauged after coating, because the layer sits where the nut runs. On a long screw the nut may travel a distance before it seats, so a tight thread becomes a slow assembly rather than a slight inconvenience.
Three assemblies where the reach is the reason for the part:
| Where it sits | The screw runs through a frame or a tube and threads into a plate or a nut at the far side. |
| When it goes wrong | The screw binds as it passes, or the nut will not run down the last part of the thread. |
| Why it happens | The body is oversized for a hole, or the key applies a side load. |
| What we control | Body matched to the smallest hole; first article assembled through the frame. |
| Where it sits | The screw holds a component at a distance from a bracket where stock lengths stop short. |
| When it goes wrong | The component hangs at an angle, or the joint loosens. |
| Why it happens | The screw is forced in, and the start at the far end is partly formed. |
| What we control | Length and thread start checked; first article mounted on the bracket. |
| Where it sits | The screw is an adjuster where the reach is the function and the thread end moves something far from the head. |
| When it goes wrong | The adjustment is inconsistent over the travel, or the screw binds part way. |
| Why it happens | The body does not suit the guide holes, and the key pushes it sideways. |
| What we control | Body and thread coverage checked; first article adjusted through the full travel. |
Four reasons that matter on a part whose difficulty is its length, each tied to something the drawing or the first article proves. All four show in the sample.
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Length and thread stated
The quotation asks for the length under the head, the thread coverage and the holes it crosses, because those three numbers define a long part. Basis: Three numbers agreed. |
Body made to pass
The plain body is made to the smallest hole the screw crosses, so it reaches its thread without binding on the way. Basis: Body matched to holes. |
|
Reached through the stack
The first article is assembled through the customer parts, because reach and nut travel only show when the screw is in place. Basis: Reach proved in assembly. |
Same length on repeat runs
Length, thread coverage and packing are recorded with the drawing revision, so a repeat batch arrives and assembles the same way. Basis: Same part across orders. |
These screws are turned or formed from stainless bar and wire, with the head and drive made at one end and the thread produced to the length on the drawing; the parts are cleaned, passivated and inspected. The first piece of every run is checked on length under the head, threaded length, body diameter, head and thread.
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A long part is made in more than one pass, with the body supported between operations so that the part itself does not deflect under the cutting force. The support is part of the process, not a convenience: an unsupported long part moves away from the tool and comes out with a body that is not round over the supported length.
The head is made first so the part can be held by it for the later operations. Holding a long part by the body instead pushes any small error along the whole length, and on a long screw that multiplication is what makes the difference between a part that assembles and one that does not.
Passivation comes last, and then packing. The parts are supported along their length so they arrive as made, because a long part that is bent in transit is scrap at the assembly station rather than at the factory.
What decides whether custom long screws pass is the length, the thread coverage and the body. The inspection agreement covers those, and the criteria come from the drawing.
Head and thread on the projector |
Thread gauged |
Material checked |
Salt-spray testing where plated |
The length under the head is checked on a sample from each batch with a length gauge, and the threaded length from the end. Both are recorded, because a part that is right overall and short of thread will not hold.
The body is checked for diameter at several points along its length, since a long body that drifts is the feature that makes a screw bind. That is a diameter check along the length rather than a hand measurement at one end.
The thread is gauged and a nut is run along the threaded length. A sample is then assembled through the customer parts: reach, nut travel and the ability to remove the screw again are the properties that matter on a long part, and they are proved by assembly.
Every batch of custom long screws 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 both lengths, and the packing specification. The records carry the drawing revision and the batch number, so a repeat order of custom long screws reaches the same point.
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 long part the first article is assembled through the customer stack, because reach is a property of the assembly rather than of the screw. 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 custom long screws are packed to the same specification, because a long part that arrives straight is half of what the customer is buying. Buyers and quality engineers visit for sample review, process discussion and supplier audits; the visit is arranged around production so the turning cell and the length inspection 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 |
Quoted per drawing: custom lengths up to 2,000 mm, subject to DFM review after drawing submission, because at that length packing and transport matter as much as machining.
Because a long part is limited by material, machine length, packing and assembly alignment rather than by the thread.
Full thread gives an adjustable nut position; partial gives a clean pass-through body. The drawing has to say which.
The body passes through every hole on the way to the thread. If it is oversized for the smallest one, the screw binds.
Supported along its length, so it arrives as made. A long screw bent in transit cannot be straightened on the line.
Length under the head, thread coverage, head and drive, finish, and the holes the screw passes through.
How a custom long screw project runs from drawing to repeat delivery:
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1
Send the drawing and the parts it crosses
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→ |
2
Length and thread coverage agreed
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→ |
3
First article assembled through
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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 length under the head, the thread coverage, the head and drive, the finish, and the holes the screw passes through.
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Length
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Thread coverage
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Head and drive
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Finish
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Pass-through holes
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Packing
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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
