Tips from the Bench

Many stone setters would agree that one of the most challenging aspects of prong setting is getting the prongs down tight on the stone. It’s easy to take this process for granted. If it’s done well, you might never notice. But doing it poorly can result in damaged or lost gemstones, or prongs that snag clothing and feel rough or sharp to the wearer.

A variety of pliers or other tools can be used to push prongs down onto the stone once the bearings have been prepared. This article will focus on prong pushers, which consist of a piece of brass or steel fitted into a wooden handle.

Most common are the flat prong pusher and the grooved prong pusher. While these tools can be used “as is,” a few modifications will make them more versatile.

Experienced stone setters often make their own prong pushers from used gravers, files or other tools. These are good options that allow them to reuse worn-out tools and customize the prong pusher for their particular needs, including creating different sizes so they can easily work on larger or smaller prongs and hard-to-reach areas.

Many stone setters will also modify the prong pusher’s basic shape, preferring a rectangular face over a square face, which tends to block the view during the setting process. You can use a table-top bench grinder to make these modifications. Just make sure you dip the tools in water frequently as you are grinding to prevent overheating.

Many jewelers also prefer a textured face on their prong pushers. While this may cause minor tool marks on the prong as it is being tightened, the prong tips are often filed down anyway. The advantage of the textured surface is that it keeps the tool from slipping and possibly chipping the stone.

There are many ways to achieve this textured surface, but one is to simply sand across the face of the tool with a relatively coarse (220 or 320 grit) sandpaper.

Another useful modification is to put a groove in the face of the prong pusher to keep it from slipping while you push down the prong. This modification is easily made with a small cylinder bur. By extending the groove across only three-quarters of the face of the tool, you can also put a “stop” in the groove. This is a great trick for working with smaller prongs because it helps you feel the tool drop into place on the prong, allowing faster and more accurate work.

-- Compiled by GIA’s Jewelry Manufacturing Arts instructors

For more information on GIA's Jewelry Manufacturing Arts program, click here

Fine jewelry represents much more than its trade value in diamonds, gemstones and precious metals. It is a personal representation of the owner’s lifestyle, status, emotion, recognition, commitment and more. That significance only amplifies how devastating the loss of a gemstone is for the owner. Even one missing accent stone renders the jewelry unwearable. Loss of a significant gemstone will also impact the retailer who sold the piece and the manufacturer who engineered and produced it.

The loosening, damage or loss of gemstones in jewelry can be attributed to two factors: poor workmanship or the absence of benchmarking standards for setting. Benchmarks are specific parameters used to compare and evaluate the acceptability of a finished product for market.

Stone loss can be avoided. Inspecting each piece and comparing it against established benchmarks for signs of vulnerability in normal wear gives the jeweler/manufacturer an opportunity to address potential problems before jewelry is offered for sale. Adopting consistent task-specific benchmarks encourages sound design and good workmanship, assuring the quality of jewelry for the consumer. Examples of the quality assurance benchmarks presented here are for setting round brilliant gemstones in traditional angled prongs (Figure 1). Prong Setting Benchmarks – Traditional Angled Prongs Figure 1: A: Prong angle is 70-80 degrees. B: Sufficient prong thickness is needed to secure the stone in place, so 40-50% of the metal is removed from the prong thickness at the bearing. C: Diamond is seated level in the bearing just above the gallery wire. There are no gaps in any bearing – the bearing is the cut made in a prong and must precisely fit the stone contour when properly set. Any gaps will allow the stone to move or loosen. D: Finished prong height is 75-85% of table height. Ample prong height allows the prong to hold up through normal wear. E: Prong contact is 33-50% of total crown distance. Adequate prong contact over the crown is critical to a stable setting. F: Prongs are rounded, polished and consistent in size and shape. Potential Errors in Workmanship for Traditional Angled Prongs Figure 2: Using the quality assurance benchmarks, you will note a bearing was not cut (lower blue arrow) and the diamond is not seated. Prong contact is insufficient (upper blue arrow) and barely secures the diamond. Figure 3: The bearing does not conform to the crown and pavilion angles of the diamond, so there are large gaps. Too much metal was removed from the prong thickness.

Prong Setting – 90 Degree Prongs

Watch the video (above) to see quality benchmarks and examples of vulnerability for setting round brilliants in 90 degree angle prong variations. You will also see applications of these quality benchmarks in actual pieces.

Understanding what to look for and following consistent quality assurance practices will enable our industry to ensure that our global consumers have the best possible jewelry experiences.

– Mark B. Mann, Director Global Jewelry Manufacturing Arts

For more information on GIA's Jewelry Manufacturing Arts program, click here.

Ergonomics is the safe and effective relationship between a worker and the work environment. For the bench jeweler who spends hours working with a bench pin, it is important to make it work efficiently and effectively for you. There are many modifications you can make to ensure this.

People prefer different bench pins, namely a flat piercing pin vs. an angled working pin. Some modifications can be used with either type, while others work better with a specific style of bench pin.

To modify a working bench pin, start with a standard wedge-shaped bench pin, measuring 133 x 59 millimeters. These are available at most jewelry tool suppliers. With the angled side facing up, draw a 15 mm long line, 13 mm in from the left edge. Make a mark 61 mm back from the front right edge and draw an angled line from that point to the end of the first line. The wood on the right side of the lines is cut away to leave the basic shape of the working bench pin. The 15 mm line is cut with a perpendicular cut. The angled line is cut at 45 degrees, tilting away from the front top, leaving a slanted surface. Holding items against that edge makes filing easier.

Whichever type of bench pin you use, the best place to start is with a piece of sandpaper. Simply smoothing the surface of the wood and gently rounding corners will make a difference you’ll feel immediately as your hands come in contact with the bench pin.

To help the bench pin hold a ring clamp securely, sand interlocking grooves with a 25 mm sanding band in the bench pin and the ring clamp. Sand the bench pin at the intersection of the first two cuts, leaving a semicircular arc with vertical sides. On the ring clamp, measure down 10 mm from each end and draw a line around the body. Sand a groove in the ring clamp following this line to create a lip at the end that will catch on the bench pin and hold it steady when in use. Sand the ring clamp groove until it mates nicely with the arc on the bench pin.

A ring-cutting fixture at the end of the bench pin is invaluable (Figure 1). To create one, file an 8-mm-wide groove in an arc around the squared end of the pin, 5 mm from the front edge. A ring shank will slip over this 5-mm-wide lip and be secured straight and square while you cut it for size. Next, use a No. 2 blade to cut a straight vertical slot into the end of the bench pin. Your saw will follow this slot when you cut ring shanks. You can also file a relief notch at the top center of the lip of the ring-cutting fixture with the narrow edge of a flat hand file centered on the saw cut. This will open up sight lines so the area you are cutting will not be obscured behind the lip of the fixture. This modification increases the accuracy of the cut and the efficiency of the operation while reducing the possibility of slipping, broken blades and injury (Figure 2).

You can also prevent rings from sliding on the bench pin while filing the insides of shanks by making a set of three grooves. Use a ball bur to cut the grooves — 2 mm, 6 mm and 10 mm wide -- in the top of the bench pin, just behind the angled diagonal cut. Each groove should be 12 mm long and aligned with the diagonal cut, side by side, parallel with the angled top edge. They should be 1-2 mm deep with at least 5 mm between them. This modification enables the jeweler to file flat inside ring contours.

A stone-holding tray can also be incorporated into the flat top of the bench pin. Mark a 12 x 22 mm rectangle and use a ball bur to carve out a shallow depression to hold the stones.

A similar feature can be added to the right side of the bench pin to hold cutting lubricant. Mark a 10 x 10 mm square and use a ball bur to carve a shallow depression, just like the one in the stone tray. Melt the cutting lubricant into the depression with a soft flame. Slightly overfill the cavity, and when it cools you can quickly wipe the cutting lubricant from your saw blades, burs and twist drills.

The more you specialize your tasks at the bench, the more specialized your modifications will become. Left-handed bench jewelers can simply mirror the locations and orientations of most of these modifications. As you continue to work, keep in mind that a few minutes with a file, bur and square- or straight-edge tool can make a significant difference in how well your bench pin works for you.

-- Compiled by GIA’s Jewelry Manufacturing Arts instructors

This is just one of the many bench tips you can learn in GIA’s Jewelry Manufacturing Arts program.

There are a few scientific methods for precisely determining karat gold purity, some destructive (fire assay) and others nondestructive (X-ray florescence). Both methods require costly equipment, special procedures and a well-lit and ventilated area. A simpler method for determining gold purity in jewelry is the “touchstone” testing process, an age-old technique that is relatively nondestructive to jewelry and offers quick results.

Use with care: Touchstone testing incorporates the use of acids, so close attention to safety and careful procedures are a must.

Touchstone testing is based on the fact that 24k gold resists all but the strongest acids. The purer the gold, the stronger the acid required to dissolve it. Measured strengths of nitric acid are used to test for 14k and lower. Aqua regia, a mixture of one part nitric acid and three parts hydrochloric acid, is used to test higher karat purity through the process of comparison and elimination.

To conduct touchstone testing, you’ll need an acid testing kit (available through jewelry tool suppliers), a well-ventilated area, two glass beakers, water, baking soda, protective gloves, 320-grit abrasive paper, safety goggles and paper towels.

Your testing kit includes a set of testing needles. Each needle has a karat gold sample on its tip and the karat value stamped on the side. Use yellow gold needles for testing yellow gold and white gold needles for testing white gold.

Begin by checking the gold jewelry piece for other stampings (e.g., quality marks or manufacturer’s marks) and make note of characteristics such as heft, color and reflectivity. If you suspect the item may not be gold, use an engraving tool and make a small notch in an unobtrusive place on the jewelry to expose fresh metal. Next, put on protective gloves and place a drop of acid from the 18k gold testing bottle over the small notch. A highly effervescent green reaction indicates base metal, and no further testing is required.

If there is little or no reaction, the piece is likely karat gold, and the next test is for purity. Follow these steps:

• Rub the jewelry of unknown karat purity gently back and forth on the testing stone to leave a thin but clearly visible metal sample. Use care to take this sample from a place not clearly visible on the jewelry and away from solder joints.
• With a testing needle, draw a question mark on the touchstone that represents the unknown metal.
• Start with the 14-karat testing needle and rub a layer next to the unknown. Label it “14.”
• Repeat this process, making a layer and then labeling with the 18-, 22- and 10-karat testing needles.
• Now choose the bottle labeled for testing 10-karat and lightly swipe the applicator across all the samples.
• After approximately 20 to 40 seconds, place the touchstone in a mixture of baking soda and water to neutralize the acid in one beaker, then rinse in water in the other beaker.
• Blot the touchstone with paper towels and observe. The 10-karat sample has dissolved, but the unknown metal is still visible. This confirms the unknown metal is finer than 10-karat.
• Next, choose the bottle labeled for testing 14-karat and swipe it across the samples just below the first test.
• Allow enough time for the acid to react and neutralize, then rinse and blot the touchstone and observe. The acid has dissolved both the 10- and 14-karat samples. The unknown metal is therefore 14-karat or slightly higher.

Always prepare the touchstone for its next use by cleaning it thoroughly. Remove the metal from the stone’s surface by placing it facedown on a piece of 320-grit abrasive paper on a flat surface. Apply moderate pressure and sand it in a circular motion until sample layers are no longer visible. Neutralize, rinse and blot dry before replacing in the kit. Always follow the manufacturer’s directions for the proper care, storage and handling of acids.

-- Compiled by GIA’s Jewelry Manufacturing Arts instructors

For more information on GIA's Jewelry Manufacturing Arts program, click here.

Master models used in mass jewelry manufacturing range from simple one-part pieces to intricate multiple-part forms. Rubber molds made from these master models are the key to reproducing consistent replicas of the original in wax form for casting. Cutting a rubber mold is a master craft in itself.

A rubber mold is heat-formed around the metal master. When it’s cured, the mold must be cut to remove the model and ensure two critical outcomes: the successful injection of molten wax to completely fill the mold cavity and the release of the resulting wax replica without distortion or breakage. Cutting a rubber mold for a plain half-round band is a fairly simple task, but cutting one for a ring with a gallery or basket setting poses certain challenges.

In this installment we present a mold cutting technique called a spiral cut, which is designed to facilitate the successful release of a cage-like wax model from a mold.

After making initial cuts and creating your mold locks, cut along the sprue, the sides of the model, the finger hole and the gallery wires. Finally, cut across flat and parallel to the top plane of the setting to expose the top of the gallery wires. Release the master.

Draw a spiral with a ballpoint pen on the top flat section of the rubber, inside the gallery wires.

Push a scalpel blade straight down into the rubber. Carefully guide the blade along the spiral. Do not force it. The blade should remain perpendicular to the top surface while cutting, and the spiral cut should be the same depth all around. The cut must stop short of cutting through the outer edge of the plug.

Next, you will cut the base of the spiral at the depth of the cut. The objective is to release the outer spiral but leave the center core attached. Use caution as you guide the blade.

The spiral cut allows the mass of rubber within the gallery cage to uncoil and release from the center outward. With the simultaneous stretching and thinning of the rubber as it’s being pulled, the mold is essentially “poured” out of the cavity through the small opening. The result is a wax model with no distortion or breakage and a rubber mold that becomes a most valuable asset in the production process.

-- Compiled by GIA’s Jewelry Manufacturing Arts instructors

For more information on GIA's Jewelry Manufacturing Arts program, click here.

 

 

Small, fine twist drills used for jewelry making will become dull with normal use. Worn cutting edges make tasks more difficult and time-consuming and can cause costly accidents, including damage to jewelry and gemstones or even injury. Maintaining the cutting surfaces on your tools will ensure clean, consistent work at the bench.

This installment will teach you how to sharpen the cutting edges of a fine twist drill. There are different styles of twist drill tips, but this example features a chisel tip. Let’s begin with a look at its anatomy.

A twist drill has two cutting surfaces, one on each side of its center axis, that are cut at an angle of approximately 60 degrees.

Notice that each of these angled surfaces is also cut at a slightly narrower angle, creating another plane. This plane creates the cutting edge as well as a relief area behind that edge. This relief area prevents contact with the metal being cut as a hole is drilled, which reduces drag and friction.

The helical groove in the twist drill is called the flute.  It acts as a channel to guide the cut material out of the hole created by the two cutting edges.

We will grind each of the relief areas to sharpen the twist drill, maintaining the same angle as these planes, which is important for the twist drill to perform properly after sharpening. The cutting edges will be honed by reducing a small amount of metal from each surface.

Begin by inserting and tightening a silicon carbide separating disk in a No. 30 hand piece of a flex shaft. Secure the worn twist drill in a screw mandrel and brace against the bench pin as you position the drill to be grinded on the relief area.

Carefully lower the separating disk to lightly touch the targeted surface. Without changing the angle, rotate the drill in the holding device and repeat on the opposite relief area plane. Once this is complete, you will have a newly sharpened twist drill. This may take a bit of practice, but it’s a valuable technique that can save time on the job.

-- Don Hughes, JMA Instructor
in collaboration with Mark B. Mann, JMA Global Director

For more information on GIA's Jewelry Manufacturing Arts program, click here.

This jewelry bench tip is a follow up to “Using a Split Mandrel for Finishing Fabricated Round Bezels,” which showed you how to modify a standard split mandrel to make an effective holding device to finish several fabricated bezels of the same dimensions. The same split mandrel can also be adapted into an efficient tool for setting multiple round faceted stones into those bezels.

Secure the modified split mandrel in a ring clamp. Insert a 3.5 mm ball bur into the No. 30 hand piece of a flex shaft and burr a hollow into the top center of the mandrel, cutting to a depth of about 2.0 mm. Follow with a 2.5 mm ball bur, centering and burring to a total depth of around 3.0 mm. You will create a void that provides clearance for the pavilion and culet of each stones to be set.

The total depth of the bezel must be at least 4.0 mm to accommodate the depth of the stone when set. Choose a finished bezel and position it on the mandrel. Secure the mandrel in a ring clamp. Measure the stone to be set and select the proper size setting bur. You will be cutting the depth of the bearing, so the top of the bezel flange is no less than 50 percent of the crown height. Cut the bearing and check the fit of the stone to make sure it is level and at the correct depth for setting.

Remove the mandrel and bezel from the ring clamp and tighten it in the hand piece on your flexible shaft. You will be filing the bezel flange to thin it slightly for ease of setting. While spinning the hand piece, use a file to bevel and reduce the thickness of the bezel flange. Clean any debris from the bezel and place a small amount of wax in the bearing to help hold the stone during the setting process. Pack and level the stone.

The bezel contact should be no less than 10 percent of the crown distance, which is the dimension along the surface of the crown from girdle (0%) to table (100%). Rotate the hand piece as you use a burnisher to apply pressure to the beveled edge of the flange, pushing the metal over the stone. Look closely to make sure there is complete 360 degree contact against the crown.

The completed bezels are ready to become a part of your fine jewelry creations. If the stones you use can take heat, the bezels can be soldered into jewelry by the traditional torch method. If they are vulnerable to heat, use a laser welder to set the bezels in place.

-- Don Hughes, JMA Instructor
in collaboration with Mark B. Mann, JMA Global Director

For more information on GIA's Jewelry Manufacturing Arts program, click here.

A bench jeweler typically uses a split mandrel to sand and finish the inside of a ring. Various grits of abrasive papers can be cut to size and inserted into the slit of the mandrel, where they are held by friction during the rotary filing process. With minor modification, you can use the split mandrel as a holding device to finish round bezels and other small jewelry components quickly and consistently.

To illustrate this, we will make a bezel for a gemstone measuring 4.5 millimeters round. The bezel will be hand-fabricated from 4 x 1 mm sterling silver flat wire. To determine the length of flat wire required to fabricate the bezel, multiply the gem’s diameter (4.5 mm) by pi (3.14) to find its circumference, which equals 14.13 mm. The bezel is cut from the flat wire, formed, soldered, then rounded and trued. The truing step, typically accomplished with a ball- or setting-style bur, is critical to rounding the inside of the bezel.

You will need to make a minor modification to the split mandrel to fit and hold the bezel for this use. Calipers, dividers and an equaling file will be required. The outside diameter of the split mandrel measures 5.5 mm and the inside diameter of the hand-fabricated bezel measures 3.5 mm, so the split mandrel must be filed down.

With the mandrel secured in the hand piece, brace it and start spinning the flexible shaft at a moderate speed. Place the equaling file flat against the mandrel shaft about 3.0 mm from the top of the tool and apply adequate pressure to begin filing down the mandrel shaft. Continue filing until the shaft diameter is reduced to 3.8 mm.

Next, squeeze the upper shaft of the split mandrel and place the bezel on it so it extends about 0.5 to 1.0 mm above the top of the tool. This makes it possible to sand the top of the bezel, too. The bezel will be held firmly in place by the tension of the split mandrel throughout the remaining steps in the finishing process.

The flexible shaft can be spun at moderate speed, and a variety of abrasives can be placed against it to smooth and polish. This technique also gives you greater hand-eye control to apply the surface finish on small areas.

A modified mandrel gives you a dual-purpose tool for sanding or cleaning up bezels and other small parts. The next installment of the GIA Insider will present a stone-setting application using a different modification of the split mandrel.

-- Don Hughes, JMA Instructor
in collaboration with Mark B. Mann, JMA Global Director

For more information on GIA's Jewelry Manufacturing Arts program, click here.

There are many types of backs available to hold earrings securely in place. Clutch, friction or butterfly backs are discs with curled-up tabs that oppose one another, acting as springs that pinch the ear post. The post has notches on it that function as stops so the clutch backs can hold the earring in place. Adjusting the tension of these springs so the earrings fit comfortably and securely is a routine service task for the bench jeweler.

Loosening the tension in the curled springs reduces the friction on the post but makes the catch less distinct, posing a very real risk of losing the earring. Tightening the curled springs, on the other hand, increases the friction on the post and gives the catch a better connection. But this can make it uncomfortable, even painful, for your customer to put on and take off the earrings.

Simply deepening the grooves on the ear post also has limitations, because the post is weakened without a noticeable effect on the catch. The curled springs bridge the notches, leaving a barely noticeable stop.

Here is a better way to tighten earring springs. First, you need to make the curvature of the springs smaller at the point of contact with the post. This allows the curls to sink deeper into the notches and create a more secure catch. Mark this point of contact on the outside thickness of the clutch back with a marker. Next, open the curled springs to the point where they can be grasped with the appropriate pair of pliers and give each spring a little extra curl at the mark you made. Then restore the original curvature to the remainder of the spring, adjusting for the desired tension as you go. In many cases, this sufficiently enhances the hold of the catch.

This may not be tight enough for some, so use a 1.0 to 1.3 mm ball burr to make miniscule indents in the curled springs of the clutch back. This will enable them to sink even deeper into the ear post notches and make the catch considerably more pronounced. Working from the top of the clutch back, simultaneously rest the ball burr on both springs as you cut a tiny indent dead center. Repeat this step from below the connection with the ear post. You will likely have to pinch the shaft of the burr between the curled springs and pull back on the burr to avoid excessive widening of the hole in the disc.

Bear in mind that commercially available clutch backs can be less than 0.2 mm thick, so it takes little to burr right through them. But very small indents can create secure stops that are safer than even the strongest possible tension between the curled springs. If properly positioned, these indents should stabilize the position of the clutch back on the post.

-- Robert Ackermann, G.G.

For more information on GIA's Jewelry Manufacturing Arts program, click here.

CAD/CAM is a term that describes the two-part process of designing three-dimensional objects on a computer (CAD) and manufacturing them with a computerized machine (CAM). For many years this technology has been essential in making products from tennis shoes to automobiles, and it is rapidly gaining importance in the jewelry industry. In fact, many experts believe CAD/CAM will be the primary process of jewelry design and manufacturing in the near future.     

CAD is an acronym for computer-aided design, but early on it stood for computer-aided drafting, since it was essentially a tool to make traditional technical drawings with a monitor and a mouse. As technology progressed, it became possible to create three-dimensional “models” within the computer environment. These “virtual solids” can be rotated and manipulated onscreen and examined from any angle, built up and cut away the same as a physical model, and even weighed before they are constructed.

For the bench jeweler, CAD modeling onscreen has more in common with wax carving than with pencil, paper and watercolors. Once the virtual model is completed to the designer’s satisfaction, the CAD file may be sent to a CAM machine for production. Rhino, Matrix, ArtCam, RhinoGold and Solidworks are some of the widely used 3-D modeling software in the jewelry industry today.

The advantages of CAD/CAM over traditional manufacturing methods are similar to the advantages of a word processor, such as Microsoft Word, over a typewriter. A typewriter produces “one-off” documents that aren’t easily changeable without starting over. But Word files can be modified easily, copied and pasted into other documents, and saved at each stage for later use.

CAD files can also be copied, changed and saved as often as the designer chooses. A model can be designed and saved, then redesigned to create literally endless variations on a theme. A file can be called up the next day or 10 years later and still be redesigned and sent to the CAM machine. Some manufacturers have stopped making master models since they only need to open the original CAD file and send it to the CAM machine to produce an exact duplicate of the master. Many smaller jewelers own just the CAD software and simply e-mail their CAD files to CAM service bureaus, which fabricate the models for them.

Besides its advantages in the manufacturing process, CAD software can work in tandem with high-tech rendering software such as V-Ray, Brazil and Maxwell to produce spectacular photorealistic images of virtual jewelry models before the actual piece is made. These images can be extremely effective marketing and sales tools. The accompanying short video should give you a sense of what the “CAD/CAM Revolution” looks like. 

-- Steve Workman
JMA Instructor
 
For more information on GIA's Jewelry Manufacturing Arts program, click here.

Chain repair is a set of fundamental skills and techniques every goldsmith needs to master, but the structure and design of the chain dictate what you need to do for a successful repair.
 
This bench trick focuses on fine cable and rope chains with tiny links made from extremely thin wire. It is difficult to manipulate these links, reconnect them and then solder them. Study the chain to determine how each link connects to the next and remove all damaged links, leaving only the sound links that will be joined back together.
 
Use a permanent marker to color some of the links near the joint so you can find the links that need to be soldered. Cut open one or more links, depending on the style of chain, and open them slightly to connect to the other section of chain. Make sure you fit the cut ends of the link together as tightly as possible to ensure a good solder joint.
 
The next and most important step is to solder the open links together so they are joined in an inconspicuous way. The chain should look as if it had never been damaged. So easy to say and so hard to do!

You will likely have problems if you apply flux and solder to the open link, then heat it directly with the torch:

• The solder might not flow to both sides of the joint
• A lump of excess solder will adhere to the link because it is impossible to cut solder into small enough pieces for fine gauge links
• Heating the links directly may fuse several links together, which means you must start over on a now shorter chain

This “Sneaky Goldsmith Trick” makes it possible for you to avoid all the pitfalls and do a clean job every time. The secret weapon is the trusty soldering pick. Normally, goldsmiths use a pick to hold a piece of solder in place or position it on the work. In this case, you will use the tip of the soldering pick to expose the clean metal and apply the flux.
 
Pick up a piece of easy solder about 1.0 mm square with the pick and heat it directly with the torch until it flows and covers the tip of the pick with a thin layer of solder. Be sure to choose a steel pick, because solder won’t adhere properly to titanium or tungsten.
 
Bring the solder-coated pick into contact with the open joint of the link. Instead of pointing the torch directly at the chain, heat the pick about 8 to 10 mm from the tip. The pick will act as a thermal conductor to carry the right amount of heat to the joint to be soldered. When the solder flows again, a small amount of solder will transfer to the joint. Lift the pick quickly. Allow the chain to cool, pickle and clean up as needed.
 
This trick simplifies the soldering process and enables the goldsmith to do better work, faster and with fewer mistakes.

-- Douglas W. Canivet
JMA Instructor
 
For more information on GIA's Jewelry Manufacturing Arts program, click here.

Gemstones that become loose in their settings can cause damage to both the gem and the setting. A regular inspection of jewelry can catch this problem in its early stages, before too much damage is done. Vector tightening prong-set stones is a quick, safe and effective way to secure gemstones.

We’ll use a four-prong head with a round brilliant-cut stone as an example. If you try to tighten the stone by simply pushing the prongs in toward the center of the stone -- seemingly the most direct way -- it probably won’t be secure. That’s because the “memory” of the metal in the prong will cause it to spring back to its original position, and the stone will still be loose. In vector tightening, you move the prongs in two different directions (vectors) to overcome the metal memory.  The prongs end up closer to the center of the stone and hold it tightly. You can use flat or chain-nose pliers to vector tighten, but parallel jaw-pliers work best.

First, gently squeeze the two prongs on the right side (upper and lower right) toward each other. Next, do the same thing with the prongs on the left side. As you squeeze the prongs toward each other, they will “slide” around the contour of the stone. Don’t squeeze the prongs too close together -- just reduce the distance between the side prongs by roughly one-third.

At this point, the space between the top two prongs and the bottom two prongs should appear too large, and the space between the two prongs on the right and left sides should appear too small.

Next, squeeze the top two prongs (upper left and upper right) toward each other so they end up with what looks like the original spacing. Repeat with the bottom prongs. The gemstone is now tight, with the prongs evenly spaced around it.

The movement of the prongs in two directions, first toward the sides and then toward the top and bottom, provides tension in the prongs so they are somewhat spring-loaded and hold on to the gemstone securely.

-- Douglas Hall
JMA Instructor
 
For more information on GIA's Jewelry Manufacturing Arts program, click here.

A worn-out bristle brush can easily be recycled into a useful tool called a whip burnisher or rotary hammer to improve or even eliminate minor imperfections and surface porosity in castings and other metal surfaces.

You’ll need the following supplies, which are available at most jewelry shops, to make a whip burnisher:

• worn-out bristle brush wheel
• flex-shaft and handpiece
• bench grinder with a coarse grit wheel and a medium grit wheel (such as a cratex wheel)
• jeweler’s saw
• sanding sticks – 320, 400 and 600 grit
• polishing machine with tripoli and rouge buffing wheels

The first step is to use the jeweler’s saw to cut off the worn-out bristle brush. This will leave just the shaft of the former brush wheel -- a piece of mild “soft” steel about an inch and a half long. This type of steel works well because it’s not hardened or tempered. It’s strong, but you can still bend it easily without breaking it.

Use the coarse grinding wheel on the bench grinder to round the end steel piece. Remove coarse grinding marks with the medium wheel, then insert the steel into the flex-shaft handpiece and spin it against 320, 400 and then 600 grit sandpaper sticks to make a smooth, rounded end. Finally, polish the rounded end with tripoli and rouge.

The last step is to make a slight bend about 6-7 mm from the end you have rounded and polished. The further you bend the stock, the more aggressive the burnisher will be when you use it. You can adjust the tool to suit your preferences as you use it.

To use the whip burnisher, insert it in the flex-shaft handpiece and spin it at medium speed. Bring a metal surface against the spinning end, and it will hammer the surface and smooth out imperfections, such as porosity. A touch of burr lubricant will improve the performance of the whip burnisher.

Lightly sand the surface of your piece with 400 and 600 grit sandpaper after burnishing it, then polish as usual.

-- Don Hughes
JMA Instructor
For more information on GIA's Jewelry Manufacturing Arts program, click here.

Jewelers have been “going green” for many years by recycling old or worn-out tools into something new and useful.

Setting burrs, normally used to cut seats in prongs, can’t be used once they become worn or damaged. But instead of throwing them away, you can create a new tool called a “rotary burnisher” to repair solder pits or minor surface porosity on a casting.

Start with an old setting burr that’s 5 mm or larger, since a larger burr will produce a better hammering action. You’ll also need a bench grinder with a coarse-cut and a medium-cut wheel.

First, use the coarse-cut wheel to grind the point or top off of the burr, making sure it is flat, then grind the two parallel sides on the burr. This will produce a sort of oval shape: two flat parallel sides and two rounded sides that still have the original teeth from the burr. Grind off these remaining teeth, being careful not to alter the shape too much.

Next, refine the new surfaces with the medium-cut grinding wheel, using the same steps as above. Make sure you remove all of the coarse grinding marks. Now you can sand the surfaces with 400-grit and then 600-grit sandpaper. Finally, polish your new rotary burnisher with tripoli and rouge. It’s important to have a high polish on your new tool: A highly polished tool will produce a polished surface.

To use your new rotary burnisher, insert it into the chuck of the flexshaft and bring the spinning burr into contact with solder pits or porous areas on the metal’s surface. It is helpful to use one of the commonly available burr lubricants as you work. The malleability of the metal will allow the surface to deform slightly, “smearing” the metal across the surface and filling in the imperfections.

After burnishing, the surface can be lightly sanded with 600-grit sandpaper and polished with tripoli and rouge. Depending on the severity of the imperfection, the rotary burnisher can greatly improve the appearance of the surface, if not eliminate the problem altogether.

-- Don Hughes
JMA Instructor
For more information on GIA's Jewelry Manufacturing Arts program, click here.

Bench jewelers hate to throw out used tools. By training and by nature we try to conserve the materials we use. An unfortunate side effect is that old burs and dull files tend to collect on our benches.
 
All is not lost, however. There is life in those tools yet. A “Sneaky Goldsmith Trick” with chemicals in your workshop can get them sharp and useful again.
 
Warning: Only bench jewelers who are familiar with the safe use of chemicals should try this trick. Acid can cause serious injury if they are not used properly.  
 
First, prepare a very strong pickle solution (an acid solution used to clean oxides and fluxes off precious metals) about twice as concentrated as usual and as warm as normal. Thoroughly clean your dull files and burs while the solution is warming. Start with an ultrasonic cleaner followed by a blast from the steamer. Continue cleaning until all traces of stuck metal are removed, then degrease using alcohol or another grease-cutting cleaner.
 
Once clean, completely submerge the tool in the pickle solution. It should be placed on edge on the bottom of the container or suspended in the solution. Burs should be suspended so only the cutting portions of the tool are submerged in the acid.
 
You will soon notice small bubbles beginning to rise from the surface of the tool. This is gas being released as the solution begins to dissolve the steel surfaces. Let the acid work for a few minutes, then remove the tool from the solution and rinse in baking soda and water to neutralize the acid. Dry it immediately to prevent rust.
 
You'll have to experiment with the exact amount of time you need to sharpen your tools this way. You should only leave them in the acid long enough to etch the cutting edges to restore sharpness; any longer and they will dissolve too much.
 
This method can be used once or twice on a tool. After that the cutting edges become too degraded for further sharpening, but don't toss them out yet. There are other “Sneaky Goldsmith Tricks” they can be used for…but that’s another story.
 
The pickle solution to dissolve steel also becomes useful with the dreaded broken drill problem. It’s not uncommon for the tiny drill bits to break off and leave part of the drill wedged into a blind hole of the piece you are working on. These pieces are virtually impossible to extract by mechanical methods without doing grievous harm to finely polished surfaces on the surrounding metal.
 
Mix up a fresh acid solution as described above. (Don't use old solution that may contain dissolved copper, which will plate out on the jewelry, leaving a pink coating on the surface that can be very difficult to remove.) Leave the item in the acid until the gas bubbles stop forming and the steel is entirely dissolved.
 
-- Douglas W. Canivet
 
For more information on GIA's Jewelry Manufacturing Arts program, click here.

Good photos of your work, or pieces you take in for repair, are invaluable. These small-scale photos, however, can be tricky to shoot without the following tips.

Rule No. 1: Always use a tripod or stand to hold your camera steady.

Close-up photos have a short focal length and a shallow depth of focus, so it can be hard to get an entire ring in focus, for example, in macro (close-up) mode. You can make the camera’s aperture smaller by using a higher number F-stop to increase the depth of focus and allow less light into the camera. But you need longer exposure times and can’t hold the camera steady enough, by hand, to get a good shot. A tripod holds the camera still and gives you the exposures you need to get a good shot.

Rule No. 2: Always use a diffuser.

Highly reflective surfaces -- like shiny jewelry -- are difficult to photograph. All too often you end up seeing the distorted reflection of everything surrounding the piece, which can be confusing and distracting. The bright reflection of the light source can also be a challenge because it causes overexposed “hot spots” in your photo.

This is where a diffuser will be a big help. Examples include:

• a piece of white copy paper
• tissue paper
• white/translucent plastic
• salvaged diffusing lenses from fluorescent lights/fixtures

The more you can fully surround the piece you are photographing with a diffuser, the better it will block out hot spots and unwanted reflections.

If not a rule, then at least a very strong suggestion: Use multiple light sources.

Single-point illumination can produce dramatic photographs with high contrast between highlights and shadow areas. Sometimes this is desirable, but if you want to see as much detail as possible in the whole piece, single-point illumination can be a problem. Cross lighting will get rid of shadows cast by single-point illumination, and more details can be seen in the piece.

Here’s what I use: a frosted, white glass globe (found at lighting supply stores); a piece of clear glass, cut to just fit through the opening of the globe; a roll of tape and a white napkin. The roll of tape is the base for the globe, and the white napkin will mask any color from the tape. Set the globe on the base with the clear glass inside. Mount your camera on a tripod and put the jewelry on the clear glass. Use a tiny bit of beeswax if the piece needs to stand upright.

There will be almost no reflections or hot spots, and you’ll get great illumination. Give it a try!

-- Douglas Hall

For more information on GIA's Jewelry Manufacturing Arts program, click here.

The best “Sneaky Goldsmith Tricks” involve taking mundane, everyday items and repurposing them as goldsmith’s tools. Two classic tricks that are valuable to detail-finish hard-to-reach spots involve a wooden toothpick and cotton packaging twine.

An ordinary round toothpick becomes a precision polishing instrument in the hands of a bench-savvy goldsmith. Cut a toothpick to a length of about 1.75 inches. Insert the blunt end into a jeweler’s hand piece. Pinch off small clump of fibers from a cotton ball and with the hand piece running at a very slow speed wind them onto the pointed end of the toothpick. You can put a drop of glue on the toothpick first for a stronger connection. With the hand piece running, transfer the polishing compound to your new tool and begin to polish the piece you’re working on. A small amount of light machine oil may help the compounds adhere to the cotton. Make up as many custom polishing tools as needed. These shop-made tools are perfect when the usual end brushes and standard items don’t suit the job.

You can also use cotton packaging twine in a similar way. Cut a piece of packaging string about two feet long. Tie a knot in the center of it to create a small loop. Hook the loop on a nail or a thumbtack mounted on the top or side of your bench. You will have two free ends of twine about a foot long each. Pull one strand toward yourself to put it under some tension, then rub a bar of rouge against the string. Repeat this action with the other strand using Tripoli or bobbing compound. A few drops of light oil on the twine will help the compound stick. Sometimes it’s hard to get the string started; in that case, you can tape the end of the string with masking tape and cut it at an angle to make a sharp point. This will enable you to thread it through, just like a sewing needle.

Once the strings are prepared, thread the Tripoli-charged strand through the part of the piece you want to polish. Pull the string toward you to put it under tension and rub the item against the string to polish it. Remember to keep the item moving and avoid concentrating all your efforts on one spot. The string is round and will quickly wear a round groove into the metal if you don’t pay close attention. When you are satisfied with the results of the Tripoli, clean the item to remove any traces of compound and repeat using the string charged with rouge.

This technique is known in the trade as “thrumming.” It has the feel of a very ancient method, possibly used by the earliest jewelry makers. It’s easy to imagine one of our hunter-gatherer ancestors using a strand of animal or vegetable fiber and some fine sand to cut and polish a small detail into a piece of shell or metal. 

Remember, attention to detail can make a piece stand out as a quality piece of workmanship versus a mass-produced or rushed-to-completion piece. Jewelry that sets itself apart from the competition is what your customer wants. If the jewelry is outstanding from the face-up view and inside and out, you will enjoy the rewards this extra work brings.

-- Gavin Brott, G.J.G

For more information on GIA's Jewelry Manufacturing Arts program, click here.

Every bench jeweler has experienced the frustration of trying to sand and polish a nearly inaccessible area on a piece of jewelry. The goldsmith who can detail these small corners and crevices can bring his or her work up to the level of fine jewelry. Anything that gives the work a cleaner, more attractive look translates into greater sales in the showcase.
 
One of my favorite “Sneaky Goldsmith Tricks” involves a lowly material not normally associated with making jewelry: fiberglass-reinforced packing tape, found in supermarkets and stationery and office supply stores. It contains many very fine fiberglass filaments that create a super-strong hold for packing parcels.
 
Bench jewelers use this tape to reinforce sanding and polishing papers. Once the tape is applied, the papers can be cut into small shapes that exactly fit the problem area you are trying to finish. (Cut the shapes you need with an old set of scissors -- the abrasives will dull the blades over time.) These custom-shaped papers are flexible, easy to hold and can reach spots that files, gravers or traditional polishing tools may not.
 
We use the packing tape in GIA’s Jewelry Arts classes. We apply a piece of tape the same length as a jeweler’s saw blade to a strip of abrasive paper and then cut it into several narrow strips that fit the saw frame. This makes it possible for students to precision sand and polish internal edges and surfaces.

– Douglas W. Canivet

For more information on GIA's Jewelry Manufacturing Arts program, click here.