Fall 2012

Inventory / To Die For

The bamboo hoops of Matthew Lewandowski

Marc Ganzglass

“Inventory” is a column that examines or presents a list, catalogue, or register.


Door-knocker earrings are a type of hollow-form jewelry that first became popular in New York in the late 1970s. They are made in gold and silver and come in a broad array of finishes and styles, including hearts, stars, trapezoids, kissing dolphins, and Nefertiti heads. The most popular, however, are bamboo hoops.

Today, you can still find bamboo hoops in jewelry shops and department stores around the city, and for sale on television channels such as the Home Shopping Network and QVC. The earrings are manufactured in small factories and sold by the pound to jewelry wholesalers, who resell them to retailers, street vendors, and larger chain stores. Unlike fashion apparel, in which new designs are developed for each season, designs in the wholesale jewelry market are constantly evolving, driven as much by the cost of gold and silver as they are by consumers’ tastes.

Image from jewelry catalogue depicting a variety of bamboo hoops.

Hollow-form jewelry is made by stamping very thin gold or silver sheet metal into two symmetrical shells that are then soldered together to create a volumetric form, giving it the appearance of expensive solid gold jewelry but at a fraction of the cost. This technique, as well as its use in mass production, dates back to the beginning of the Industrial Revolution and the development of high-speed punch presses that could stamp out large quantities of parts with great precision. The manufacturing process led to a whole new class of consumer goods that approximated high-style luxury items, even as the ease and speed of production allowed for popular imagery to be quickly incorporated into their designs. The job of rendering the panoply of forms fell on the shoulders of the tool- and diemaker. Part sculptor, part technician, the tool- and diemaker was responsible for turning each new design into an accurate three-dimensional engraving that could be used to stamp out as many units as the market could bear.

The process begins with a design on paper. The toolmaker translates this sketch into a working drawing describing the exact shape, profile, and elevation of the piece. The working drawing is transferred to a block of steel, which is then carved by hand into a three-dimensional form, after which fine details are engraved into the surface. The steel block is then hardened; this is the master model called a hub. Next, the hub is pushed into a heated steel block using a hydraulic press. This negative image of the hub is called the die. With the die completed, the toolmaker pushes yet another block of steel into the negative form to produce a second master model called a forcer—the positive form used in the actual stamping of the jewelry. The pair of forcer and die is called a die-set and is sent to the manufacturer for use in production. The original hub is kept by the toolmaker in case the die-set needs to be replaced.

Subscribe to access our entire archive.
Log In and read it now.