Long Socket Screws, Long Plug Socket Screws

We make long socket screws in carbon steel with a nickel plate, with partially threaded shanks and lengths made to the drawing. The threaded length and the plating thickness are agreed together, and the socket is proved with your key after plating.

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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.

What Long Socket Screws Are

Long socket screws are socket head cap screws supplied in lengths well beyond the standard range, used to span a deep stack of parts. The part recorded here is carbon steel with a nickel plate, quoted with lengths made to the drawing.

Long length. A fastener whose shank passes through more than one component before the thread engages.

Cap head, hexagon socket. A tall head with a deep socket, so torque is applied with a key rather than a bit.

Nickel plate. A hard, bright deposit that resists wear and looks like a finished part, rather than a sacrificial zinc layer.

Partial thread. A plain shank over most of the length, with the thread at the point end.

They are used on machinery frames, clamp plates, die sets, conveyor structures and equipment where the fixing has to reach through a spacer, a tube or a stack of plates before it threads.

Nickel Changes the Long Screw in Three Places

Nickel is not zinc. Zinc protects by giving itself up: it corrodes first so the steel does not. Nickel is a hard barrier deposit that protects by covering, wears well, and looks bright. On a long socket screw that difference shows in three places at once.

On long socket screws the first is friction along the thread. A plated layer adds a small amount to every flank of every turn, and on a long thread the total effect is cumulative: a screw that turns freely by hand for the first twenty millimetres can stiffen as the plated thread travels deeper. That is felt most in a tapped hole, and it is why nickel-plated parts are driven with a key and a steady hand rather than at speed.

The second is coverage inside the socket. A cap head has a deep hexagon, and plating reaches the floor of a deep pocket less evenly than it reaches an open face. A nickel layer that is thick on the head and thin at the socket floor is invisible, and the socket floor is exactly where the key bears.

The third is what happens at a scratch. Nickel does not sacrifice itself, so a scored shank or a chipped corner exposes steel that will rust in place. On a long screw that is buried through several parts, that rust is inside the joint where it cannot be seen or cleaned, which is why nickel is chosen for appearance and wear rather than for a wet environment.

What nickel gives long socket screws is a hard, smooth surface that wears slowly, and an appearance that does not need painting or a second operation. On exposed machine frames, where the fixings are part of the look, that is a real advantage over a dull zinc finish.

The length then compounds all three. Every effect that is small on a 20 mm screw is felt over the whole run on a long one, which is why plated long screws are measured and proved after plating rather than before.

Length, Thread and Coating

The recorded product covers the long range, with lengths made to the drawing. Custom lengths up to 2,000 mm, subject to DFM review after drawing submission. The quotation for long socket screws carries the overall length, the threaded length, the head diameter and height, the socket size, the thread and the coating thickness.

On long socket screws the threaded length is stated separately because the shank is usually partially threaded, and the boundary between thread and shank has to fall inside the clamped part. A drawing that gives only the overall length leaves that boundary to the supplier’s standard, which may not match the joint.

Coating thickness belongs in the table because nickel is a deposit, not a conversion. It adds a measurable amount to the thread and inside the socket, and on a long part the accumulated effect on driving friction is worth controlling rather than discovering.

Length is measured under the head, which is the datum that agrees with the stack. On a long screw the difference between measuring from the top of the head and from under it is the head height, and that difference decides whether the screw reaches.

What Long Socket Screws Give and Costs

Four properties decide long socket screws, and each one carries a cost:

The value of long socket screws is a single fixing where a stud and nut would need access at both ends, with a finish that looks like part of the machine rather than a bought-in fastener.

The cost is that plating and length interact: the finish that protects the outside of the head is also the finish that has to survive being driven through a long thread.

The trade is a long socket screw that has to carry torque to a thread far from the head.

Nickel and the Coating Options

The recorded finish is nickel, applied over carbon steel. The table compares it with the finishes that actually compete for the same parts, because on a long screw the choice is usually between appearance, friction and corrosion.

Surface Options for Long Socket Screws

Where the joint is wet, nickel on steel is the wrong answer: a scratch in a long buried shank becomes a rust source inside the assembly. Stainless, or a zinc finish that sacrifices itself, is the honest specification for those conditions.

Where the joint is dry and the parts are seen, nickel gives a hard bright surface that stays consistent across a run, and it does not transfer a grey film onto hands the way a soft zinc finish can.

Where Long Socket Screws Are Used

Three settings where a socket head has to reach through a stack:

Why Shi Shi Tong for Long Socket Screws

Four reasons that matter on a plated part whose length multiplies small effects, each tied to something the drawing or the first article has to prove:

How Long Socket Screws Are Made

These screws are headed on single-die machines that form the cap head and the under-head fillet, broached with a hexagonal punch, thread rolled over the agreed length and then nickel plated. The first part of every run is measured on head diameter and height, socket size and depth, overall length and threaded length, and the thread is gauged again after plating.

Thread rolling sets the boundary that makes the part a joint component, and on a long screw the rolls run a long distance in one pass. A pitch drift that would be invisible over twenty millimetres shows over a hundred as a thread that engages at the head end and stiffens near the point.

Plating long socket screws is where the finish and the fit are decided together. Nickel builds on every surface, so the socket and the thread are gauged after the deposit, and a sample is driven with the production key to confirm that the socket floor is still reachable. Handling between operations is also a rule on this length: the parts are kept straight in trays, because a bent plated shank cannot be recovered.

The under-head fillet is the last feature checked. On a long screw most of the clamp passes through that fillet, and a plating that builds there changes where the head bears when the pocket is shallow.

Inspection: Length, Socket and Plating

What decides whether long socket screws pass is the length, the socket, the thread and the plating. The inspection agreement covers those, and the criteria come from the drawing.

Socket and boundary on the projector	Thread re-checked after the deposit
Core hardness checked	Salt-spray testing of the nickel layer

Overall length is measured under the head and the threaded length separately. Head diameter and height are measured with the socket, because the socket is cut into the head and the plating is added over both.

The socket is proved with the production key after plating and inspected for coverage at the floor. A socket that is plated thin at the floor looks correct and starts to mark under load, which on a long screw shows as a joint that cannot be re-opened.

Coating thickness is checked on the head, the shank and inside the socket, since the three can differ on a part with this much geometry. A sample goes into salt spray, and the batch is judged on the shank and the socket rather than on the outside of the head.

Certificates and Material Documentation

Every batch is traceable to the wire it was made from and to the plating lot that finished it. The grade and heat number appear on the material certificate supplied with the parts, and the plating thickness is recorded for the batch.

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 post-plating thread, and the plating and RoHS reports. The documents carry the drawing revision and the batch number, so a repeat order of long socket screws reaches and drives the same way.

Customers and Projects

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 plated screw the first article is driven with the production key through the customer stack. Buyers visit during the process to review samples.

Buyers and quality engineers visit for sample review, process discussion and supplier audits; the visit is arranged around production so the headers, the thread rolling station 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

Related Products and Guides

Technical Guides

Long Thin Screws: Drawing and Manufacturing Requirements What to put on the drawing for long parts: datum, shank, thread position and handling. Read the guide

Plating Requirements for Screw Surface Treatment What a plating specification has to state so the fit survives. Read the guide

Products

Socket Head Cap Screw The standard length version of this head. Socket Head Cap Screw	100mm Socket Screws The stainless long socket screw. 100mm Socket Screws	Low Head Socket Head Cap Screws A reduced head in the same family. Low Head Socket Head Cap Screws
Hex Socket Flat Head Cap Screws A flush head with a socket drive. Hex Socket Flat Head Cap Screws	Long Thin Screws Long parts across head forms. Long Thin Screws	Cross Recessed Pan Head Screws A pan head for the same frames. Cross Recessed Pan Head Screws

Long Socket Screw FAQ

Order Long Socket Screws

How a long plated socket screw project runs from drawing to repeat delivery:

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.