advanced metal The pachinko balls rotate freely in their 18k gold flanged cages. The bracelet is 102 x 11mm (4 x 7 16 in.). facetjewelry.

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1 advanced metal The pachinko balls rotate freely in their 18k gold flanged cages. The bracelet is 102 x 11mm (4 x 7 16 in.). FCT-MWON0216_ART Kalmbach Publishing Co. This material may not be reproduced in any form without permission from the publisher. facetjewelry.com

2 A picture is worth a thousand words. To capture the simple elegance of design and the complexity of execution, here are the pictures to tell the story of a remarkable work of jewelry art. by Abrasha In 1986, while on vacation in Kyoto, Japan, I visited one of the ubiquitous pachinko parlors. These parlors are loud and smoky, often with hundreds of machines in one parlor. Players sit nearly motionless, controlling the velocity of small steel pachinko balls that are propelled vertically into the machine and cascade through a maze of pins sticking out of the machine s colorful background. When balls are deflected into holes, the player wins additional balls, which can be exchanged for trinkets. I refer to playing pachinko as mechanized meditation, because the Japanese would spend hours in front of the machines, seemingly at one with the pachinko and unaware of their surroundings. I thought that I might want to make a piece of jewelry with the balls at some point, so I took a number of them with me as souvenirs. Several years later, a colleague at a craft show wore an interesting bracelet, which was nothing more than a large industrial thrust bearing. When I saw that bracelet, the design for my pachinko ball bracelet immediately became crystal clear. After making several models of the basic elements, I had a good working model. As you ll see in the process photos, one part of the working model became a necessary tool a drilling jig. In 1992, I completed Royal Pachinko Ball Bracelet, which is now part of the permanent collection of the Oakland Museum of California. I later made a second rendition of the design, Imperial Pachinko Ball Bracelet. This industrial thrust bearing triggered Abrasha s conceptualization of the pachinko ball bracelets. 59

3 [1] The main steel plates [1] For the original Royal Pachinko Ball Bracelet, I made the two main steel plates entirely by hand, without the help of a lathe or milling machine. I had the main steel plates of the Imperial Pachinko Ball Bracelet machined on a lathe from 316-grade 1.2mm thick (16-gauge) stainless steel. I based the dimensions for both bracelets on my artistic choices and the size of the pachinko balls. I then created this blueprint for my machinist. The double-ended mill bit in the picture is custom-ground to the exact size for the holes. These tools are much more precise than drilling a hole with a drill press or sawing and filing by hand. If you are interested in working with steel, see Steel Connection, opposite [2 7] Make the flange disks [2] With a pair of dividers, mark out ten 18mm ( in.) circles on an 18k gold 24-gauge (0.5mm) sheet. This is the first step for fabricating the parts that make up the cage flanges, which hold the pachinko balls in place. [3] Use a jeweler s saw and 2/0 saw blades to cut out the flange disks. [4] Use a center punch to dimple the centers of each flange disk. Drill a hole at the center of each flange disk. [5] A custom-made lathe jig holds two flange disks in the lathe. The lathe spins the metal, and a cutting tool removes any edge irregularities to make the flange disks perfectly circular. In the absence of a lathe, use files and sandpaper to make the flange disks as perfectly circular as possible. [6] Saw out the centers of the flange disks by hand. [7] Mount the flange disks into the lathe, and bore the center holes to an exact 12mm ( in.) diameter. In the absence of a lathe, use an 11mm ball bur or cylinder file with a flex shaft to shape the flange disks center holes as perfectly circular as possible. 7 60

4 [8 9] Make the domes 10 [10 13] Make the flanged domes [10] Use a graver to angle the inside edges of the flange disks to ensure that the domes fit without gaps. Process photos by Abrasha. 8 [8] Use a circle cutter to cut out ten disks of 18k gold 24-gauge (0.5mm) sheet, and dome them in a dapping block. Make sure the ten domes are slightly smaller than needed. Annealing the disks between moves from larger hemispheres to consecutively smaller hemispheres will keep the metal from tearing due to stress. Cooling annealed 18k gold in denatured alcohol, which results in reddish-colored domes, subjects the metal to less shock than quenching in water and prevents firescale. Direct quenching of annealed metal in alcohol may cause it to ignite. Wait 30 seconds after heating the metal to avoid this dangerous side effect [11] File flat any irregular edges on the domes while keeping the domes all the same height. steel connection [12] Solder the flange disks to the domes, with two steel spacers slightly elevating the flange disks to make sure that the bottom edges of the domes protrude below the flange disks. [13] Shown from the back, the protrusion will assist in locking the two main steel plates in place when drilling the holes for the rivets. There are more than 150 grades of stainless steel 15 are most commonly used. The 300-series stainless steels (303, 304, 316) are nice and bright. Each of the grades in the 300-series has very different working qualities. Visit these Web sites for more information: 9 [9] Tamp a pachinko ball into the domes to ensure a perfect fit. whatis.asp what_austenitic.asp jindalstainless.com/stainless-steel-grades.html products/products.asp 61

5 [14 16] Drill the flanged domes and the main steel plates [14] Use a custom-made drilling jig and a drill press to drill the holes for the rivets in five of the flanged domes. For guidelines on making a drilling jig, see Make a Specialized Tool, below. Use rivets to prevent the flanged domes from rotating after the first holes have been drilled. (Editor s Note: Although it is not advisable to use your dapping block as a support when drilling, in this situation it accommodates the dome of the flanged dome piece, holding the flange level. Only attempt this if you have an advanced skill-level and are using your own tools.) [15] Insert the first five flanged domes into the holes of the main steel plates. The bottom edges of the flanged domes protrude through one main steel plate enough so that a second main steel plate can be attached. With the flanged domes acting as registration points, the holes in the flanged domes will serve as the guides. Drill all the holes in the two main steel plates. Use rivets to prevent the flanged domes from rotating after the first holes have been drilled. Apply a small piece of tape to each main steel plate, and mark one as top and one as bottom to help keep your alignment correct. [16] Once all holes are drilled, file and sand smooth the bottom edges of all the flanged domes until they are flush with the main steel plates. make a Specialized tool In traditional riveting, you need to set one rivet first and then drill the rest of your holes to maintain alignment. But a complex piece requires a specialized tool, such as a drilling jig, for aligning the parts and providing exact registration for drilling. a b c Making a drilling jig requires advanced planning and three key elements: 1) a point of registration 2) precision measurements 3) a sturdy material A point of registration can be a central element to all the parts. It can also be a tab that will lock the parts in place during drilling and then be removed from each part before assembly. With the featured drilling jig, the center hole that houses the pachinko ball [a] becomes the point of registration. The holes in one of the stainless steel plates from the original model are used as a jig to drill the holes in the first five flanged domes [b]. The registration must be in exactly the same place for all parts being drilled, so precision measurements, up to a 100th of a millimeter, will help to ensure that the holes will line up at the final assembly [c]. A steel jig will keep the guide holes in their exact place and correct size, but 16-gauge (1.3mm) brass and nickel will also work well. 62

6 17 18 [17 20] Make the cage flange pieces [17] Use dividers to mark the top three-quarters of the dome of all ten flanged domes. [18] Use a jeweler s saw to remove the top three-quarters of the dome of all ten flanged domes. File and sand the edges smooth to create the cage flange pieces. [19] Use a lathe to trim the cage flange pieces to the exact final dimensions. [20] Use the bottom main steel plate as a guide for drilling the holes in the remaining five cage flange pieces. Use rivets to prevent the cage flange pieces from rotating after the first holes have been drilled. [21 22] Prepare the main steel plates 21 [21] Sand both main steel plates to remove burs from all the edges [22] Polish the inside and outside edges of the main steel plates to a high sheen. The surfaces of both plates are matte finished with texturing cloths

7 [23 25] Make the rivets and the spacers [26 28] Assemble the bracelet 23 [23] Make 25 rivets by melting a ball at the end of 24k gold 20-gauge (0.8mm) wire. 24 [24] Roughly shape the rivets by inserting them in a steel plate and tapping them with a fine, concave dapping punch or staking tool. 25 [25] Finish the rivet heads precisely with a needle file while holding the rivet in a pin vise. Make the spacers. Cut 25 2mm ( 5 64-in.) lengths of 18k gold tubing. The tubing must have an inside diameter of 0.8mm to fit snugly over the rivets. Sand the tubing level on both ends [26] Take an inventory of all the parts (70 total) before assembly. Plate all 18k gold plates with 24k gold to match metal colors. [27] Make gauge (0.8mm) silver pins in lengths from 10 35mm ( in.) in 1mm ( 1 32-in.) increments. Flare one end of each silver pin. Attach the cage flanges to the bottom main steel plate by inserting the 25 silver pins in a graduated sequence from longest to shortest. [28] Slide the spacers over the pins. [29 31] Mount the top main steel plate [29] Line up the top main steel plate over one pin at a time with a pair of tweezers. Instead of trying to line up all 25 pins at once, line up the longest pin first, then continue to slide the plate down onto each graduated pin. [30] Insert the pachinko balls. [31] Mount the remaining cage flanges, and hold the whole bracelet together with tape. 64

8 [32 35] Insert the rivets [32] Replace the silver pins by carefully pushing them out with the gold rivets. Take care that the spacers do not fall out during this process, because it is very difficult to get the spacers back into the right position without scratching the steel plates. Slightly bend the gold rivets after they are inserted so they do not fall out. [33] Make rivet heads on the other side of the rivets with the crosspeen side of a riveting hammer. [34] Round the rivet heads with a concave punch. [35] The finished Imperial Pachinko Ball Bracelet. 35 materials 5 pachinko balls Stainless steel sheet: 316-grade, 16 gauge (1.3mm), 12 x 12 in. (30.5 x 30.5cm) Gold sheet: 18k, 24 gauge (0.5mm), 4 x 2 in. (102 x 51mm) Gold solders: hard, medium, easy Gold wire: 24k, 20 gauge (0.8mm), 12 in. (30.5cm) Gold tubing: 18k, 0.8mm inside diameter, 12 in. (30.5cm) Sterling silver wire: 20 gauge, in. (87.6cm) Brass or nickel sheet: 16 gauge (1.3mm) (optional) tools & supplies Lathe with cutting tools Milling machine Drill press Custom-made mill bits Dividers Jeweler s saw, 2/0 blades Center punch Custom-made lathe jig Jeweler s files, various cuts dedicated to steel use Jeweler s files, various cuts dedicated to gold and silver use Sandpaper, various grits Ball bur or cylinder file: 11mm Flex shaft Circle cutter Dapping block Dapping punches Plastic sledgehammer Denatured alcohol (optional) Graver Soldering station: torch, solder, fire-resistant surface, pickle pot with pickle, flux, steel tweezers (cross-locking and precision), copper tongs Finishing items: polishing equipment, steel polishing compounds and buffs dedicated to steel use, texturing cloths Concave dapping punches or custom-made staking tool Pin vise Tube-cutting jig 24k-gold plating solution (optional) Rectifier and complete plating system (optional) Cross-peen or riveting hammer 65