Furniture Connecting Screw Knock Down Bolt K4605

The K4605 Furniture Connecting Screw In Eleven Photographed Positions

Eleven frames were shot for this screw and every one of them is a photograph of the same part in a different arrangement: twelve screws laid out in a fan, twelve in a ring, nine standing on their heads, three leaning together, two lying side by side, and single screws standing and lying. What the set is for is the shape. A screw this long is hard to judge from one view, because the head, the neck, the shank and the thread sit in a line and a single angle flattens one of them. Turned around eleven times, each of those four features gets a frame where it is seen edge on.

None of the eleven frames carries a printed measurement. There is no dimension line, no figure in a corner and no scale bar on any of them, so nothing in this description is quoted from the artwork as a size. Length, shank diameter and thread are set by the issued drawing for K4605 and are confirmed against a sample before an order is packed. That is stated here plainly because a buyer who needs to match a screw to an existing hole should be working from the drawing, not from a photograph of a screw lying on a grey cloth.

Head, Neck, Shank, Collar And Thread

Read from the head down, the screw has five features and the frames show all five. The head is a low pan: a shallow dome with a flat rim, wide enough to bear on a washer or on the face of a panel. In the middle of the head is a star socket, six lobes cut into the metal, deep enough that a driver engages before it turns. That socket is the working end of the screw, and it is the feature the fan frames show most clearly, twelve sockets pointing at the camera at once.

Under the head the screw narrows into a short neck, then steps out again into the shank. The neck is the part that lets the head sit down against a surface without the shank rubbing the edge of the hole. The shank itself is a plain cylinder, bright and unthreaded for most of its length, and it is the longest section on the screw. Toward the far end there is a turned collar, a slight flange that stands proud of the shank, and beyond the collar the metal is threaded for a short distance to the tip.

The thread is coarse and short: a few turns at the very end of the screw, cut to bite into a threaded insert, a nut or a socket rather than to travel the length of the screw. Between the collar and the thread there is a small relief, which is what stops the collar from being drawn into the material it bears on. Lay the screw on its side, as two of the frames do, and the order is unmistakable: pan head, neck, long plain shank, collar, short thread.

What The Frames Do Not Say

A photograph can show a shape and a finish; it cannot show a specification. These frames do not give the overall length, the shank diameter, the thread size, the thread pitch, the depth of the socket or the bearing diameter of the head, and this page does not invent any of them. They also do not carry a grade mark, a standard number or a maker's stamp beyond the wordmark in the corner, so no claim is made here about tensile strength, load rating or the exact alloy. What the frames do support is the geometry, the drive type and the finish, and that is what the description sticks to.

The finish is bright and even on all eleven frames. Every screw in every frame is the same silver, with the same soft sheen on the shank and the same darker tone down inside the socket where the light does not reach. There is no colour variation between screws in a frame and none between frames, which is what you want to see in a plated batch: a barrel that has been plated unevenly shows up as patchy tone on exactly this kind of plain shank. Nothing on these frames suggests patchiness.

The Names This Screw Sells Under

Three names are used for this part and all three are current in the trade. It is a furniture connecting screw when the job is named: the screw that connects one panel to the next in a piece of furniture that is delivered flat and built on site. It is a furniture connector bolt when the part is bought as hardware, which is how the catalogues list it alongside barrel nuts and cap nuts. And it is a knock down bolt when the assembly method is the point, because the joint it makes can be taken apart again with the same driver that closed it.

Two neighbouring parts are worth separating from it, because they are bought for the same shelf and they are not interchangeable with this screw. A cam bolt is turned into the panel and then locked by a cam disc; the cam bolt has a head that stays visible until the disc covers it, and the locking action happens in the disc, not in the screw. A confirmat screw is a case-hardened screw with a wide flat head and a stepped core, driven straight into a drilled hole in particleboard without any insert at all. This screw is neither: it has a star socket, a long plain shank and a short thread meant for a mating thread.

Where A Knock Down Bolt Is Used

The commonest place is flat pack furniture: wardrobes, beds, desks, shelving and cabinet carcases that are shipped knocked down and assembled in a room. The screw goes through a clearance hole in the first panel, picks up the thread in the insert or nut set in the second, and is turned from the socket side until the two faces meet. Because the drive is a socket rather than a slot, the driver stays engaged while the joint comes up tight, which matters on a long screw where the last turns carry the most resistance.

The second place is a joint that has to come apart again: exhibition stands, shop fittings,partition systems and furniture that is moved between sites. The third is repair. Where a joint has worked loose and the original fitting has stripped, a connecting screw of this pattern can be run through a fresh clearance hole into a new insert and the panel pulled back into line, often without dismantling the whole carcase.

On a bench the checks that matter are the ones this shape makes possible. Run a finger round the socket: six clean lobes and no burr at the mouth mean the driver will not cam out. Stand the screw on its head: a shank that leans means the head and the shank are not square, and that screw will pull a panel off line. Turn the collar between finger and thumb: it should be concentric with the shank, not eccentric. Start the thread into a matching nut by hand: it should run in for the first turns without force, which is how a rolled thread is told from a cut one.

How The Screw Closes A Joint

The joint has three parts: the screw, a clearance hole in the panel it passes through, and a threaded seat in the panel it pulls against. The head bears on the first panel, the shank runs free through the clearance hole, the collar seats against the face of the second panel or against the insert flange, and the thread engages the seat. Turning the socket draws the thread in, the collar stops against the face, and every further turn pulls the two panels together. The plain shank is what allows that travel without the screw cutting its own thread into the clearance hole on the way.

Two things go wrong when the screw is mismatched. If the clearance hole is tight, the shank binds and the head turns the panel instead of the screw. If the thread is coarse for the insert, the screw starts but stalls before the faces meet, and the socket takes the strain. Both are avoided by matching the screw to the drawing and to the insert it is meant to run into, which is why the sizes on this page are left to the drawing rather than guessed from the frames.

What A Buyer Should Send With An Enquiry

• The model number K4605, so the drawing that goes out is the right one.
• The overall length and the shank diameter wanted, if the standard drawing is not the right match.
• The thread size and the type of seat it runs into: insert, nut, socket or a threaded plate.
• The panel thickness at the joint, since that decides how much plain shank has to be free.
• The drive wanted at the head, if a star socket is not the one already in use on the line.
• The finish and the carton count per size, if the order is going into retail packing.

Packing, Cartons And Mixed Sizes

A screw this shape is packed by count, and the count per carton is agreed with the order rather than fixed by the frames. Sizes are kept apart in the carton, because two lengths of the same screw differ by a few turns of shank and are almost impossible to sort once they are loose in a bin. Where an order carries several lengths, each length goes into its own bag inside the carton, and the bag is marked with the length and the model. Export cartons are marked with the model, the count, the size and the destination, and the marking is agreed before packing starts so that the carton matches the packing list on arrival.

The screw ships as hardware, not as a finished assembly. It is not supplied with a driver, a washer or a nut unless the order asks for them, and it is not packed in a retail blister unless the order is written that way. For a first order the practical unit is the carton count of one size, so that the thread and the plating can be checked against a sample in the buyer's own insert before the rest of the size is committed.

Star Socket Or Cross Slot

On an assembly line the driver decides which screw goes in the hole, so the drive at the head of a connecting screw has to match the bit already in the operator's hand. A cross slot screw is turned with a Phillips or a Pozidriv bit: the bit is cheap and it is everywhere, but the slot in the head of a cross slot screw is shallow, and the last turns of a screw that is pulling one panel face onto another are exactly where a shallow slot cams out and the bit spins. A screw with a star socket takes a six lobe bit that sits deeper in the head, so the bit is still driving the screw when the joint comes up tight.

The screws on these frames are the star socket type, and every frame that shows the head shows the socket cut deep into it. That is worth checking on a sample rather than on a photograph, because the depth of a socket is the difference between a screw that can be driven hard and a screw that has to be coaxed. A buyer moving from a cross slot screw to this screw does not have to change the thread or the length; the screw changes only at the point where the driver enters it.

What Wears First On A Connecting Screw

Four things on a connecting screw wear in service, and they wear in a known order. The socket lobes wear first: every assembly cycle puts the bit against the same six corners, and a screw that has been in and out a dozen times will show polished corners inside the socket. The start of the thread wears next, because that is the turn that has to find the insert without the help of the shank. The face of the collar wears third, and it wears as a bright ring where it has been pressed against the seat. The plating on the shank wears last, and only where the shank has been rubbing a clearance hole.

A screw that is checked against those four points tells you how the joint it came out of was treated. A screw with worn socket corners and a clean collar was driven hard into a joint that never closed. A screw with a bright collar and a damaged thread start was pulled against a seat that did not line up with the insert. Neither is a fault in the screw; both are worth knowing before the same screw is ordered again for the same joint.

Three Ways A Connecting Screw Fails On Site

The first failure is a clearance hole that is too small for the shank. The screw starts, the shank binds in the first panel, and the head turns the panel instead of the screw; the joint never closes and the socket takes the load of the driver. The second is a thread that does not match the seat: the screw enters the insert, stalls a turn or two in, and stops with the panels still apart. The third is a screw that is too long for the joint, so the thread bottoms out in the seat before the faces meet and the collar never gets to bear.

All three failures look the same from a distance, which is a screw standing proud of a panel that will not close. They are told apart at the bench: back the screw out and look at where the marking is. A bright ring on the shank says the clearance hole is tight. A bright ring on the thread start and none on the collar says the thread is wrong for the seat. A bright ring on the collar with the thread fully engaged says the screw is too long for the joint.

Care, Re Use And Replacement

A connecting screw is a reusable part within limits. The socket, the thread and the collar all take a number of assembly cycles, and a screw that is kept out of grit and driven with the right bit will outlast the furniture it holds. A screw should not be re used once the socket corners are rounded, because the next driver will cam out and mark the panel around the head. Nor should a screw be re used if the collar has been deformed, since a deformed collar will not seat square and the joint it closes will pull the panels out of line.

Replacement is by model and by size rather than by eye. Two connecting screws from different batches can look identical on a bench and differ in thread pitch, and the difference only shows when one of them is driven into the seat. That is the reason the size is quoted from the drawing on every order of this screw, and the reason a replacement screw should be ordered against K4605 rather than picked out of a mixed box.

How This Screw Is Made

The screw starts as a blank cut from wire, and the head is formed on the blank in one blow. The pan shape and the flat rim come out of that blow, and so does the pad the socket is cut into. The socket is milled into the head after forming, six lobes at a time, and the depth of the socket is set on the machine rather than by hand. A screw whose socket is shallow is a screw that was milled with the tool set wrong, and it shows as a bright, thin socket on the bench.

The shank of the screw is turned to bring it concentric with the head, and the collar is formed in the same pass, which is why a good screw has a collar that runs true when the screw is spun between fingers. The thread on the screw is rolled, not cut: the metal is pressed into shape, so the thread grain follows the shank and the thread start is rounded rather than sharp. A rolled thread is what lets this screw find a seat by hand, and it is the reason the thread on the screw does not gall on the first assembly.

Plating comes last, and it is the step that decides how the screw looks. The screw is cleaned, plated and passivated, and the whole screw goes into the bath, socket included, so the inside of the socket carries the same finish as the shank. A screw that shows bare metal inside the socket has missed part of the bath; a screw that shows a patchy shank has been plated in a barrel that was too full. Neither appears on the eleven frames, where every screw in every frame carries the same even silver.

Sizes, Threads And What To Quote

This screw is made in a range of lengths and shank diameters, and the range is quoted by size rather than by description. A buyer ordering the screw states the length, the shank diameter and the thread the screw has to run into, and the drawing that comes back fixes the rest: the head diameter, the socket size, the collar thickness and the length of thread on the screw. Where a joint already exists, the simplest way to order the screw is to send the insert or the nut the screw will meet, so that the thread on the screw is matched to the seat rather than guessed.

Two screws of the same length can carry different threads, and the difference is invisible until the screw is driven. That is why a mixed box of connecting screws is a bad source of spares: the screw that looks right may be a thread that stalls. Ordering the screw against K4605 keeps the thread, the collar and the socket tied to one drawing, and it is the only way to be sure that the second carton of screw matches the first.

Short Answers On This Screw

Is it a wood screw? No. The thread is short and coarse and it is meant for a mating thread, an insert or a nut. Driving it straight into timber would strip the hole long before the joint closed.

Is it a cam fitting? No. A cam fitting locks with a disc turned in the panel face. This screw locks by its own thread, and the only thing that turns it is the socket in the head.

Does the head show? On most assemblies the head sits in a counterbore or under a cap, so the face of the panel closes over it. The frames show the head plainly because that is the only way to show the drive.

Can it be re used? Yes, within reason. The thread and the socket take a number of assembly cycles without damage, which is what makes a knock down bolt useful on furniture that is moved or stored flat.

What is the plating? The frames show a bright, even, silver finish over the whole screw, socket included. The specification for the plating is stated on the drawing and confirmed on the sample, not read off a photograph.

A screw is the simplest part in a furniture fitting set and the one that decides whether the joint closes square. K4605 is made as a furniture connecting screw with a star socket head, a plain shank long enough to pass through a panel, and a short thread that pulls against a seat. The eleven frames on this page exist to show that shape from enough angles that the geometry is unambiguous, and the figures are left where they belong, on the drawing.

This furniture connector bolt is supplied by Guangzhou Gorgeous Intelligent Technology Co., Ltd., a furniture hardware maker working to export orders. Quantity, finish, carton marking and packing are agreed per order, and the drive, the thread and the length are fixed by the drawing for K4605. A buyer matching a screw to an existing joint should send the model number with the insert type and the panel thickness, and the drawing that comes back is the one to check against the sample before the order is packed.

For a first order the practical step is a carton of one size, checked on the bench against the insert it has to run into, so that the thread start, the socket depth and the collar are all confirmed before the rest of the order is committed. A knock down bolt that fits the first time saves a whole assembly line the cost of sorting it out later.