This article is the second installment written by Prof. Dr. Erhard Brepohl discussing the different types of jewelry catches and what type of jewelry they are each suited for.
The first requirement of all catches is that they secure neckpieces and bracelets in such a way that they will not fall off the wearer. Once this is accomplished, there are other concerns that should be addressed.
It is unrealistic to expect a single “ideal” catch that can fulfill all these expectations. For this reason, the history of jewelry has several categories of catches with countless variations in each style.
Spring rings and box catches are the most common closures used for chains and bracelets, perhaps because they lend themselves to inexpensive mass production.These catches have become so familiar that they are often used without consideration to how they fit into the whole design of a piece. Some goldsmiths even use mass produced catches in their creations when competing in competitions! This is regrettable because failure to consider the catch as an integral part of the design can diminish an entire piece.
Making catches requires a high level of skill, but the rewards, in both technical and aesthetic satisfaction, make the effort worthwhile. The following examples should only serve for inspiration, and may need to be altered for your particular use. It is part of the creative process when designing and drawing the piece to create the most suitable catch and to incorporate it into the entire design of the work.
|Type of Closure||Preferred
|Direction of Opening as
related to direction of Pull
of Chain or Bracelet
|Box clasp with||Chain, bracelet||spring||opposite||longitudinal|
|Bayonet clasp||Chain, bracelet||spring||identical||rotational|
|Screw clasp||Chain, bracelet||friction||identical||rotational|
|Box clasp||Chain, bracelet||spring||identical||not required|
|slide clasp||Chain||friction||transverse||not required|
|Open tube||Chain||tension||transverse||transverse & longitudinal|
|Table 12.1 Overview of necklace and bracelet closures.|
In this simple catch (figure 12.23), a cross bar on one end of a chain is free to pivot so it can be laid flat along the chain. This allows it to pass through a ring on the opposite end of the chain. When allowed to hang, the bar is pulled perpendicular and cannot pass back through the ring, thus securing the clasp.
The design is not complicated – the bar is nothing more than a short length of wire with a jump ring soldered onto the middle to provide the connection to the chain. The opposing jump ring should be just large enough that the bar with its jump ring barely fits through.
It is nearly impossible for the bar to slip out of its ring accidentally, but to be absolutely safe, solder another jump ring onto the opposing one (to create a “figure 8” ). When the bar is passed through both, the effectiveness of the catch is doubled – even if it slides through one ring, the odds of it passing through both are extremely low. The bar looks more finished if the ends of the small rod are balled up into small spheres as shown.
The crossbar catch can only work if the section of chain to which the bar is attached can also fit through the opposing jump ring. In the case of a thick chain, it might be necessary to use a smaller loop in the section immediately adjacent to the catch, as seen in figure 12.23.
It would be difficult to imagine a catch more basic than a hook. The basic shape is easily bent up from round wire (figure 12.24). The free end of the hook should if possible be long and bent around so that it sits tightly against the jump ring. The opposing jump ring should be large enough that the hook just fits through it.
The security of a hook depends on the tensile strength of the material used to make it. A hook made from thin annealed copper, for example, will simply not stand up to normal wear, no matter how beautifully fashioned it is.
Hooks also work best when they are under some tension. In the case of a necklace catch, the weight of the pendant will keep the chain pulled taut, making the hook secure. When a chain is hanging loosely, as is typically the case in bracelets, it is necessary that the hook and ring snap tightly together.
Variations on the hook clasp are too numerous to list. One possibility is to make the hook from sheet metal rather than wire, as shown in figure 12.25. This has obvious advantages for wide bracelets.
Also shown here are several possible interpretations that can be modified to meet specific needs. The catches shown in figure 12.26 illustrate a “fitted hook” that snaps into its housing. The wire neckpiece in figure 12.27a is bent up from a simple round wire and hung onto the forged ends of the lower part. The joint is like a hook catch which is permanently locked in place because the end of the wire has been balled up after being inserted through the hole. The hook for the catch is bent up from round wire. Security in use comes from the springiness of the hoop and the weight of the front, lower portion of the neckpiece.
The hoop in figure 12.27b is closed with a double hook which is functional as well as decorative. A precondition for its effectiveness is the springiness of the hoop.
Two unusual solutions are shown in figure 12.27c. The ends of the thick wire that makes up the hoop that encircles the neck are forged out. On the left, the material is hammered into a claw-like sleeve that will catch the tapered arm of the pendant. This connection is used to hold microphones into their stands. On the right we see the neck wire bent into a hook that engages a loop cut into (or soldered onto) the arm of the pendant. Both variations require that the pendant be relatively heavy in order to keep the parts under tension.
The term comes from the lentil-like shape of this traditional catch, though in our modern age it might just as readily be called an “aspirin” shape (figure 12.28). The body of the catch consists of a flattened hollow bead that has a ring attached on one side. The side of the bead is pierced by a slot that ends directly opposite the fixed ring.
The other end of the slot has a round hole, creating a sort of elongated keyhole shape. A ring is fitted with a short length of wire, the end of which has a ball. To engage the catch, the ball is fitted into the hole and drawn around the circumference of the bead until it stops. Tension on the chain keeps the catch closed.
To make this catch, form a circular band from a strip of sheet material. Cut out two circles and dome them slightly. Solder one onto the strip, then drill a hole in the wall. The other dome can now be soldered on and the edges filed smooth.
Saw a slot the takes up at least one-third of the circumference and even it out with needle files. A jump ring can now be soldered onto the wall of the bead, directly opposite the end of the slot. Make a ball of the exact size of the hole and solder it onto the end of a short length of wire. This is fitted with a ring that will join it to the chain. As with any catch, minor adjustments might be needed to make the parts fit smoothly together.
There are many possible variations on this mechanism. If the links of a chain were spherical (or pearls or beads, for instance) an more appropriate shape would be a sphere. In this case omit the ring and make the clasp by soldering two deep domes together. The slot is cut along the seam between the two halves.
In the case of a round wire link, the better choice of clasps might be similar to the lentil but without the domes. For proper strength, use a slightly thicker metal to make the strip. The catch will blend nicely into the rhythm of the chain; the fact that the mechanism is visible adds interest.
In the variation shown in figure 12.29, the lentil shape has been replaced by an open rectangular frame. The ball has been changed into a flat disk that lays snugly against the inside of the frame when the catch is secured.
The principle of the lentil catch can be altered to make a hidden catch, an example of which is seen in figure 12.30. Narrow sheet metal links are connected with each other by round jump rings – the frame of the catch with its drilled hole and slit is soldered onto the last link of the chain.
The bracelet seen in figure 12.31 takes this catch to its extreme. The clam shell-shaped links are made of domed sheet metal portions soldered onto frames that are each bent up from flat strips. Holes are made into the frames through which the ends of the wire frame of the next link are placed. The links are joined to each other by inserting the ends of the frame of one unit into the hole on its neighbor. The ends are bent outward slightly (cotter pin style) to join the links. The frame is left somewhat wider on the catch unit to provide for the drilled hole and slot. The ball of the catch is soldered onto the next link, making a completely invisible catch.
The spring ring clasp is perhaps the most familiar of all necklace closures (figure 12.32). They are commonly used on inexpensive chains though they are also seen on expensive pieces. Of course it is possible to make spring rings by hand, but the high quality and low cost of machine made versions make this unnecessary.
Every spring ring has a small jump ring by which it is attached to the chain. This is soldered onto the loop during manufacture, but arranged so its joint remains open. When the chain is connected this ring remains unsoldered because the heat of soldering would destroy the springiness of the catch. Where added security is needed – as in the case of a particularly expensive pendant – the connecting ring can be sealed closed with a low-melting tin-based solder.
Wear on a spring ring usually occurs at the attaching jump ring. Though it is possible to remove the spring and repair the ring, this is usually not worth the bother. The rings are cheap enough that it is more efficient to remove the worn clasp and replace it with a new one.
Spring rings should never be placed into pickle because the steel spring causes an ion exchange that will cause copper flashing (plating) on the work. If the chain needs to be pickled it can be hung into the bath in such a way that the clasp is not immersed, or the clasp can be removed.
This traditional clasp, seen in figure 12.33, has long been associated with strands of pearls, though it is by no means limited to that application. The clasp is simple and lends itself to mass production which means, of course, that they are inexpensive. The specifications of the tongue are critical, so mass produced clasps of mediocre quality should be avoided. For consistent quality and long wear, the tongue (or hook) must be of precisely the right thickness and shape. It is possible to refine the shape of commercial hooks to improve their “snap.”
To make the catch, draw the shape of the unit and plan the location of each of the struts. Draw in a strip of metal that extends at a right angle outward from the “floor” of the catch. Saw this shape from sheet metal approximately 0.5 mm thick. Use a needle file to score a V-groove at the point where each strut meets the floor. Bend these pieces upright and solder each of the bends to strengthen the scored area.
Cut the tongue from a hard springy alloy, typically 14K gold or nickel silver. Test the tongue in the catch and file both units as necessary until they slide together smoothly and lock securely. The idea is that the tongue first hooks around the end strut then slides into place between the struts on either side of the catch. To release, the sides of the catch are pinched together. This makes the tongue narrower and allows it to slip out of its position.
When the action is perfect (and not before!) the struts are filed to a low and uniform height and the roof of the clasp is soldered on. This is a piece of sheet metal sawn to the same shape as the floor. A jump ring is attached to one end to connect the catch to its chain.
Catches for multiple strand chains can be made using the same principle (figure 12.33b). This catch is not recommended for very heavy necklaces, such as multiple strands of glass beads.
This variation on the catch described above is shown in figure 12.34. It is more secure and therefore sometimes preferred for particularly expensive strands because it has two points of contact. This variation will be used to describe an alternate construction method, though either this or the one described above will work for either catch.
Start by sawing out two identical pieces to be the floor and roof of the catch. To simplify registration, fold a sheet in half and saw out both pieces at once, leaving the fold, of course, until last. Solder short pieces of square wire into position as shown in the diagram, noting that they can extend outside the dimensions of the floor – excess is easily trimmed off later. The jump ring that will connect the catch to the strand is soldered on to one end at this time.
Saw the tongue in the shape shown and test it against the catch before the roof is soldered on. This makes it much easier to see where refinements are needed. When the fit is tight and the action smooth, solder the roof into place and cut away any excess wire that projects from the catch.
A third variation, shown in figure 12.35, lends itself especially to bracelets. The frame of the catch is made from square or rectangular wire, bent into a “U” whose ends are bent inward to form short stops. This unit is soldered onto a rectangular floor plate. The tongue is sawn from sheet metal and embellished with spheres (or other shapes, including bezels) that will offer the pinch points. Assuming the bracelet is hinged, a tubing of the appropriate size and length is soldered to the end of the tongue.
The action and grasp of the tongue is tested and the pieces are filed as necessary to make a perfect catch. The roof is then soldered on, a tubing knuckle is attached to the back end of the catch and the seams are filed smooth.
This clutch mechanism, named after its application in securing a bayonet onto a rife, is shown in figure 12.36. The rod is inserted into a tube-like sleeve so that its small projecting pin enters a slot in the side of the tube. The rod is pressed against a spring, rotated, and recoils to seat the pin in the end of the track.
The inner rod can be made of solid wire or a tube that has been capped on both ends, depending on the size of the catch. It is matched with a sturdy tube into which it makes a snug fit. The tube is capped at one end and a jump ring is attached there to connect to the chain.
Use a saw to cut the track, following any of the examples shown in figure 12.37. The idea in every case is to guarantee that the pin “turns the corner” and is seated in the tip of the slot. In order to release the catch, the rod must be pressed against the spring and rotated – an action that probably won’t happen by accident.
In order to lock the spring into position, curl the first coil outward so it has a larger diameter than the tube. When the spring is forced into the tube this tension will keep it in place. It is also possible to secure the spring into place with epoxy, but be certain to use only a tiny amount!
Figure 12.38 shows a sophisticated version of a bayonet clasp in which the mechanism is hidden. This version lends itself to silk cords or similar necklace materials that will need to be glued. The open tube on each side of the catch (#1 and #5) become caps into which a cord can be glued.
The catch is built on tubing in three sizes that slide together. Cut a section of the middle size (#2) and saw the J-shaped track into it. Cap a section of a smaller tube (#1) with a piece of sheet metal. When sawing off the excess metal allow a small tab to remain – this will become the pin that travels into the catch.
When #1 and #2 are working smoothly, solder the tube with the track into the largest sleeve. At the other end, insert a piece of the same tubing used in #1 and solder it into position. In order to ensure smooth action the end of the spring should have a face plate; a small disk that will slide easily along the inner walls of the tube. This is cut from sheet (or by slicing off a tiny section of a thick round wire) and tin-soldered to the spring. The wire is held in place by friction or glue as described above.
This threaded mechanism can be modified to blend into the design of a piece unobtrusively. In traditional ivory and bone necklaces it is common to carve the catch from the same material. In the case of metal jewelry, the shapes of the beads can often be adapted to the form of the catch.
The most basic version is shown in figure 12.39 and consists of two identical sections of tubing. Both are capped on one end and drilled to accept a wire onto which a bead has been drawn. This wire will be bent up to make a jump ring and of course is free to rotate independent of the catch. A jump ring connection that was fixed to the catch would cause the necklace to wind up as the catch was being closed.
A thick-walled tube is threaded with a tap and die, cut to the correct length, and soldered into the outer tube. Obviously care must be taken in selecting these tubes to ensure a tight fit. A rod of the correct diameter is selected and tapped with matching threads. When the pieces are confirmed, a short length of the threaded section is sawn off and soldered into the other piece of the catch. It is useful to bevel the tip of the threaded section slightly to make it easier to engage the threads.
Many variations can be worked on the threaded closure, a few of which are seen in figure 12.40. In the first example, two spheres are purchased or made by soldering together two dapped domes. A tube is threaded on its interior walls with a die and a matching rod is cut with threads to make a tight fit. These are then soldered into position as shown at (a).
In the case of 12.40b, a single sphere is made to enclose the catch. One dome is decked and a threaded rod is soldered into its center. To make the other piece, start by soldering a section of tubing onto a piece of sheet. Drill a hole through the sheet and thread the interior of the tube, then solder the whole unit to a hemispherical dome. Note that the same kind of jump ring connection is used.
The variation shown in figure 12.40c might be seen as a hybrid of the first two. Like the first, it has a significant length of threads, which clearly contributes to its strength. Like (b), the clasp is a single sphere. As before, cut and shape all the pieces, but avoid soldering them all together until the threaded sections have been proved to work.
The familiar safety catch, shown here in figures 12.41 and 12.42, consists of a loop of wire that snaps into place on a small ball attached to the opposite half of the catch. As shown, either variation is possible, but neither complements the sophisticated clean lines of the hidden catch.
Though difficult in the telling, threaded closures are easy to make if you have a tap and die. They lend themselves to a wide range of use, as shown briefly in figure 12.43, where the catch is “camouflaged” to work well in a variety of situations.
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