On a German grandfather clock with two broken (steel) rods on the strike side, I repaired them in this way, and it should be applicable to brass or bronze.
Drive out the broken plug in the brass screw.
In a lathe, cut off the tapered section and reform the plug and taper to original dimensions.
You now have a rod that is much shorter than the original, in my case, 55 mm (45mm taper and 10mm of plug).
On the other end, weld (or braze if brass) 55mm plus of the same or similar material. Clean up the weld and polish the rod (blue it, if it is a steel rod that was previously blued).
Drive the brass screw back onto the rod with bearing/shaft Locktite.
Tune the rod by carefully shortening it to suit.
A couple of things to note.
- I believe the length, mass and taper of the rod are the important criteria that determine how the note sounds and sustains. The small portion you weld on is restoring the length and mass, and the rod is not going to notice if that small piece is not metallurgically identical. A good, full depth weld is essential.
- To drive the slug out of the brass screw, first open up the screw slot with a Dremel burr or endmill, before drilling. Drill just deep enough to reach the slug. The drill must be smaller than the slug diameter so that there is a shoulder left in the screw for the repaired rod to stop against.
- To heat blue long steel chime rods with a flame. It's difficult to heat evenly if the rod is stationery so, chuck the slug end in a drill, held in a vice so the rod is horizontal. The drill trigger should press on the vice sliding jaw so that the drill turns slowly. Start at the far end of the rod, keep the flame moving, not too close to the rod. The slug end in the drill won't get hot enough to blue but it's not going to be seen.
Michael
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