ADVANCED MATERIALS & PROCESSES | JANUARY/FEBRUARY 2025 16 cupping process following the last roll-pass when the blank is at recrystallization temperature. Metalworkers quickly transfer the hot blanks from annealing furnace to cupping press, forming the bell between a set of upper and lower dies, as well as the center-hole. Prior to machine forming, the cupping process was much more laborious. It involved one cymbalsmith along with a two or three-person crew, hammering a stack of heated blanks layered over a cup-shaped concave die with convex hammers and/or a convex-matched die. The result from this method was not exactly precise. Cymbal cups were far from consistent in size and shape, significantly affecting the sound quality of the finished cymbals. Following the cupping process, the blank is now a raw cymbal. Next, the metalworker cuts the diameter (circle-sheared or stamped) to correct size (Fig. 1). HAMMERING A raw cymbal (cupped, but not hammered, trimmed, or lathed) will exhibit a range of tones when struck. Drummers can play the raw cymbal “as is.” Sold as such, drummers use the raw cymbal for a unique and individual sound. However, for intentional shaping of the sound, cymbal- smiths hammer the raw cymbal. This ancient metalworking process (hammering) is no less relevant for today’s cymbal- smith. The practice of hand-hammering cymbals is an art consistently employed by cymbalsmiths for millennia and continues in our modern era with the use of both old and new tools (Figs. 2 and 3), techniques, and arduous physical and mental focus. The plastic deformation resulting from hammering moves the metal and induces residual stress/strain into the metal (Fig. 4), changing vibration characteristics[2]. A hand-hammered cymbal (Fig. 5) was prepared for microscopic evaluation. Two areas, the bell and midway through the cymbal profile, were examined (Figs. 6 and 7)[3]. Both samples exhibited “a non-homogeneous microstructure consisting of lightly colored, possibly tin rich, elongated pools. The pools are well distributed throughout the darker colored, copper-rich matrix, but vary in size and shape. Additionally, stress lines are visible within the pools.” During hammering, the material stress experienced by the bronze metal is significant. Proper casting, heat treatment, quench, and subsequent cold working is critical for achieving a ductile, yet tough metal that can withstand constant plastic deformation. Figure 8 shows an example of a hand-hammered cymbal that experienced cracking at the bell and mid- profile. Examination of the metallurgy Fig. 1 — Raw cymbal before (left) and after (right) circle-shearing. Fig. 2 — A cymbalsmith’s hammer workbench. Fig. 3 — Fixtures for shape adjustment and control. Fig. 4 — The “potato chip” effect of residual stress from hammering. Fig. 5 — Turkish hand-hammered cymbal. Fig. 6 — Sample 1: 500×, SLAC etchant, FAP-015 Rev. J. Average microhardness 246-274 HV500, ASTM E384. Fig. 7 — Sample 2: 500×, SLAC etchant, FAP-015 Rev. J. Average microhardness 246274 HV500, ASTM E384.
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