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This note is written, as always, in honor of David Betts (1947-2022), the man who taught us how to notch bridges, how to be a piano technician, and how to be human. Each time notching and pinning a bridge, one learns something new. There are proud moments and way more "are you dumb?" moments.     Notching: The timing - The preferred working situation is to notch without disruption, such as field work and daily chores. But pianos have to be tuned and tuning is where income is earned. Normally the two bridges take about 1.5 days to be notched. This time, it took more than 4 half-days. However it is an opportunity to practice concentration when there are only a couple hours available during the day to work with the chisels. The work - The maple for the bridge cap this time is extremely difficult to carve. Maybe if the cap was glued downside up, the surface would be easier to chisel. I will pay more attention to wood grain direction next time changing bridge caps. For carving the rough maple, I pressed the chisel down with all my might under the left hand and pushed in lots of control with the right hand. Many carved surfaces were rough with chipped wood. It is ok, keep the flow going. When all notches were carved, the surface was sanded with 150 grid paper to remove chips, then with 220 grid paper to smooth the surface. The main lesson here is to keep the flow going, do not try to make each notch perfect for the first run. Pinning:
Precaution - Along the location of the bridges, shim wedges below between the soundboard and the piano beam. Without the shims, the soundboard would want to spit out the pins while one is trying to drive them in. According to observation on western and eastern made pianos, the bridge pins are about 3 to 4mm high above the bridge top. To keep the flow going, the pins are hammered down a hair higher than 4mm. I found it secure to retrain my eyes for the 4mm height with a ruler every quarter of the bridge. Driving in the pins - A heavier metal hammer can help driving the pins easier. When a pin is to be pounded in, watch if the pin-bottom is actually in the hole rather than anywhere else. They are thin pins! I held the pin on its bottom with two fingers of the left hand as a guide. So the pins won't tilt nor misbehave under the hammer. With small motion, hammer the pins down to finger thickness level. Place a nail punch on top of the half-way-in bridge pin, use small motion to hammer the pin to >4mm height above the bridge. The hand that is holding the punch can feel where the pin wants to wrongly bend. This maybe affected by how we swing the hammers. Push the punch against or to the opposite dirrection of the wrongly-bending tendency while hammering. The small hammer swinging motion can help prevent the pins from bending, as well. Even out the pin height - One can get very impatient, especially when the work is almost done and when repetitive motion is to be applied. Calm down! Use the nail punch and that heavy hammer to even out the pin height to 3mm on treble bridge and 4mm on the bass bridge. Different shops may have different pin height preference. Constantly check the height with a ruler. Deep breathing and concentration can be of big help until the work is done. This is the note this time. Next time, hopefully the skill could be improved a bit and, of course, new notes and new "aren't you stupid" statements will be made. Comments are closed.
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