Why Chime Hammer Positioning is required
Mechanical clock chime hammer positioning is easy to do, and only involves bending the hammer head wires. Upon the initial installation, this was done by the clock maker as well. When replacing a clock movement you need to bend the chime hammers to the chime rods. This is why the hammer heads are on bendable wires. They are meant to be bent into the perfect position. It is not uncommon to bend them an inch this way or that way. The clock movement will not have the hammers in the perfect spot to make the correct sound when hitting the rods. This is why chime hammer positioning is so important.
Clock Chime Hammer Positioning
A mechanical clock movement has hammers that need to be bent into their final position. The clock-chime hammer position should be so the tops of the hammer heads are about 1/4 inch down from the chime block. The hammers need to be 1/8 inch away from the rod when at rest. In other words, bend the hammer wires so the head is 1/8 away from the chime rod. This spacing between the head and the rod is so it will not thud or double strike.
Tuning the mechanical clock chime
Down the line, and one hammer at a time, repeat this process. Continue in this manner until you can lift and drop the hammer to create a crisp sound. If each hammer head is done this way the clock will have a nice song in the end. Often a customer will say the sound is not correct. It is because of improper hammer positioning that this occurs. When you perform the above directions correctly the sound is beautiful.
Positioning the 340 / 341 series
The 340 and 341 Hermle clock movement series went through a change in the hammer wires. The hammer heads used to be on wires now they are made on flat bars. This is dealt with in the same way as above, it is just not as easy to bend. The hammer head is on the skinny end of the bar, the bar gets wider as it goes back toward the roll pin. The point to bend this bar is at the place where it goes from skinny to wide with needle nose pliers. The overall assembly will be higher from the chime block slightly. That is if swapping out the movement with the wire hammer head rod older style. It is an option to raise the entire chimeblock with a shim underneath it to help with this. It is not an absolute requirement, bending the hammer arms are usually sufficient.
For a clean crisp chime sound
Adjust the hammer wires
Should be about 1/8 away at rest
Sometimes they are bent extreme
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