the drum’s tune. T e two rims act as a
suspension system to keep pressure off the drum’s shell and head. Alumi- num die castings are preferred because they are consistent, lightweight, cost eff ective and ma- chinable. T e diecasting operation can produce perfectly round rims with a relatively small amount of labor. T e castings also hold up to the demanding physical stress that comes with being a part of the percussion section. T e overall sound of drums are
grand pianos. Until this develop- ment, patented in 1825 but not commonly used until decades later, piano frames lacked the necessary strength to resist the strain of the strings, which led to ever-rising pitch. Cast iron’s high
The grand piano puts thou- sands of pounds of pressure on its cast iron frame.
compressive strength withstands the inward pressure created by the piano’s strings, improv- ing tone and consis- tency. T e plate, which can weigh up to 400 lbs., begins just behind the keyboard and stretches to the rear
improved by the casting process, because roll-formed rims require welds to correct imperfections, which can lead to stretching and less than ideal performance.
Grand Pianos Since the mid-19th century, metal
castings have been an integral part of
of the piano. T e strings of the instru- ment originate at a tuning pin, which appears to be attached to the cast metal plate. In fact, the pin extends through the plate and only makes contact with the large oak casing, the piano’s other major structural feature. T e casting and wooden casing together support between 25,000 and 35,000 lbs. of pressure, corralling the strings between
the tuning and hitch pins at the rear. While the large sand casting sounds simple enough, calling it a plate belies the intricacy that goes into the engi- neered component. “In terms of size and complexity, the plate has some very interesting challenges from a casting standpoint,” according to Bob Berger, director of customer satisfaction, Steinway and Sons, Long Island City, N.Y. “With a relatively imbalanced shape, it has a tendency to move during cooling.” T at imbalance stems in part from the intricate passageways that must be cast into the rear of the plate, where strings of diff erent pitches pass under, over and around each other. T e plates also are designed with several cast-in holes that lighten the massive pieces of metal and also contribute to the acoustic signature of the instrument. T e metalcasting process used to
produce the plates in pianos remains traditional, from the development of patterns to pouring in sand molds, but each is unique to the model of piano that it is made for.
Castings
Precision Metal
Make sure you’re Getting all the pieces.
At JENCAST, we pride ourselves on being a world class, full-scale manufacturing services provider. We bring every piece of the puzzle when it comes to delivering the industry’s highest quality components. From initial product design, to our robust production capacities in both foundry and fabrication, we have you covered.
Combine that with our list of added-value services, such as surface coatings, in-house CNC machining, sub or complete product assembly, and testing
capabilities, we’re able to supply you with turnkey components or products of superior quality and insure zero-defect availability.
P.O. Box 1509 / Coffeyville, KS 67337
www.jencast.com
Contact JENCAST today at 800-331-3551 or visit us online at
www.jencast.com.
22 | METAL CASTING DESIGN & PURCHASING | Sept/Oct 2014
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