Expert: Martin Meyer - 9/9/2009

Question
I purchased a "coffin" grandfather clock a few years ago. When the shipment came, there were some chime rods that had been broken off. It's a bim bam striking clock. The "bim" has 4 hammers, and the "bam" has 5 hammers. The only 2 sources for clock parts that I new of was Timesavers and LaRose (LaRose is no longer in business). I work on clocks, but I have no idea how to figure out which length chime rods to purchase to get a nice sounding bim bam. The lengths in the catalogs do not call out the "note" that the chime rod would represent, so I have way of selecting a grouping. I have ordered several chime rods and tried them out but all of them put my teeth on edge when it chimes. All of the bim bam chime rod sets in the catalogs are all to short for this clock, the notes would be too high. Is there some type of rule of thumb that I can use when selecting chime rods?  

Answer
Hi Robert,

Replacing chime rods is a big problem, and I can't give you a very encouraging answer. There are other sources for chime rods, such as Merritts Antiques (www.merritts.com) and Empire Clock, but their selections will be about the same as Timesavers.

When you say that you "tried out" several rods, I assume that you mean that you installed the rods into the chime block and screwed them in firmly. Most of the sound comes from the resonance of the clock case itself rather than from the rod. If not installed, you won't really know what the rod will sound like. Related to this, there are at least several different thread sizes for mounting the rods in the block. This sometimes causes difficulties in finding compatible rods, particularly in antique clocks. Most chime rod sets available are really made for modern clocks. Modern Bim-Bam clocks almost invariably come in sets of two or four rods. I don't recall ever seeing a set of bim-bam rods long enough for a longcase clock in any of the catalogs.

Chime rods need to be purchased in tuned sets; trying to replace individual rods never results in an acceptable tone. In your case, of course, there will be no set available that matches your original setup. The actual musical note of a chime rod is never indicated, without any exception that I have seen. Also, there is absolutely no rule of thumb for selecting chime rods by tone. Not only the length of the rod, but the type of metal used and the rod's thickness also affect tone.

It is conceivable that you could find a strike-side set of four chime rods to replace the 4-rod "bim". The strike side hits all hammers simultaneously, and so is a chord, and sounds musically acceptable. The chime side plays notes (rods) individually, and so does not sound like a chord when all rods are struck simultaneously. It is possible to find descriptions of the notes in the Westminster, Whittington, etc. melodies in musical notation form. I don't know if this would help you select a five-rod combination, from a chime-side set of 8 rods, which would constitute a chord (I'm not musical and don't read music).

Theoretically, chime rods are tuned higher by filing or grinding off a bit of the end of the rod, and tuned lower by filing off some metal near the top where the rod becomes thin. I have never been able to do this successfully, nor have I spoken with anyone who could.  http://www.clockmasteronline.com