Repair Worn Clapper
July 14, 2008 at 6:11 pm #10920fryczechParticipant
Our church is restoring two cast iron bells, a 30″ and 48″. Both are American Bell and approximately 90 years old. The clappers on both bells are very flat at the point where they hit the bell. Do flatten clappers affect tone quality? I had thought about cutting the clapper rod, rotating the clappers 90 degrees and welding the rod back. The weld point on the rod would be re-enforced with a pipe sleeve. Does anyone see any problem with doing this? Thank you. Henry
July 14, 2008 at 7:46 pm #13982hjlongMember
I would do nothing as the strike point will be distributed ove a larger area by the flattening of the clapper and will cause less damage to the bell than a smaller strike point.
July 22, 2008 at 12:37 pm #13983John EachusMember
worn clappers in cast iron bells do not affext the tonal quality of the bell sound.
Worn clappers in cast bronze bells however, do affect the tonal quality of a bell sound. The flattened clapper emphasises the musical partials of a bell, which are harsher sounding than the prime or “hum” tone of the bell. Clappers in bronze bells should be kept round by sanding the clappper.
August 14, 2008 at 4:14 pm #13984fryczechParticipant
I initially thought that the flatness of the clapper was due to wear over the past 80 years or so. However I’m having second thoughts. The flat spots on each side of the clapper on the 48″ cast iron bell are so large, while there is no noticeable wear on the inside of the bell itself. It now seems to me that it is also possible that the flat sections of the clappers could have been done intentionally at the factory. The clappers could have been grinded or filed down at the factory in order to get the right tolerance (between the clapper and the bell) for the spring to do its job properly. Or might the factory have filed the flat spots on the clapper to reduce the chances of cracking the bell? Any other thoughts on this?
July 28, 2010 at 5:35 pm #13985TowerguyMember
Seems reasonable to me. If they did make the flat spots it was probably to make the sound warmer. I don’t know that it really makes a difference, as john stated though. It seems to be common for the clapper to wear faster than the bell. Could be the alloy of the clapper is different than the bell?
July 29, 2010 at 2:08 pm #13986Green GrassMember
Bell clappers are cast with a softer metal, so the wear occurs to the clapper, which is easy & inexpensive to replace, whereas, the wear of the inside of the bell, negatively affects bell longevity.
For bronze bells, iron alloy bells sound the bell with a brighter sound, and bronze clappers sound a bell with a mellow sound. Each carillonneur has a preference.
The more round a clapper is, the clearer the sound produced is.
Cast iron bells are purely noise makers, i.e. an iron bell has no specific musical note propduced and no specific musical partials. The flatter the clapper, the more surface area vibrations produced. The larger the cast iron bell, the heavier the bell vibrations, thus the farther the sound would travel.
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