I wanted to trim 4 mm from Tokiwa damper heads for better geometry in a 1927 Leonard upright. Here’s the jig I built to get the job done.
The soundboard was tapered (diaphramized in Steinway terminology). First contour lines were routed into the board, and then the board was sanded to the contour lines on the stroke sander.
Profile of countour lines tapers the board from 0.26″ to 0.33″
The video shows use of the stroke sander to achieve the taper by sanding to the contour lines.
Ribs were shaped to a radius of 60 feet, then glued to the soundboard using cauls and compressed air clamping pressure. The photo below shows the last rib in the cauls. Typically I clamped 3 or 4 at a time.
After the ribs were glued, a radius was planed onto the ribs. This is a craftsman touch. Few will ever crawl under the piano to inspect this detail.
The cobbler’s children go without shoes. But this piano technician is breaking out of that paradigm. New to my living room is a Steinway and Sons Model A-3 built in New York in 1922. After I completed three days of work on it, the piano is very pleasing to play. At some time, it will be completely rebuilt; but for now, it is a very nice “daily driver”, to borrow from classic car enthusiast lingo. That time will not come until the high-end restoration of the 6’3″ Charles Stieff (1911) is complete.
An update on the Rebuild of Stieff 28334 has been a long time in coming. I’ve been disappointed with my inability to focus energy on the project! But progress has been made.
Cauls for gluing ribs to soundboard. Note the concave or convex shape for top and bottom cauls. These are sixty foot radiuses.
Prior to working with the actual ($$) new sound board, a sound board mockup was prepared using inexpensive quarter-inch plywood. This step was taken to work out the bugs in the system before working with the new spruce board.
For the mockup, I used some clear fir as ribs that was available at no cost. The picture below shows a jig with a 60 foot radius for shaping the topside of the ribs.
Below, the mockup progressed with the ribs fitted to the frame.
The mockup continued by gluing “ribs” to “sound board”. A few issues were noticed, and I was glad that I did this mockup, so I could proceed with confidence. The cauls use mill hose pressurized at 30 psi. I’m doing four at a time, and progressively moving cauls to a new position as glue dries.
Below is the completed “trial soundboard” which fit well when placed back in the frame.
Work is now complete on the key set and key frame of the 1916 Chickering Quarter Grand. This work is foundational to a well performing piano action. It’s the “user interface”!
- Keys rebushed
- New key tops, replacing prior poorly installed keytops
- Refinished sharps
- New Wessell Nickel and Gross key pins
- New Wessell Nickel and Gross capstans
- Keyframe retrofitted with glide bolts