McGuire Piano Blog
After completing work on the bottom board and keyframe, I’m preparing the piano for restringing.
Preparation for Restringing
Additional work to be performed before restringing
- Soundboard cracks will be shimmed
- Separated ribs will be re-glued to the soundboard
- New tuning pin bushings will be installed.
An Adam Schaaf player piano recently arrived in my shop for a complete rebuild. I’ll be doing the piano work, and the player work will go to a player expert. I’m pleased that my client has recognized the need for good piano work to precede good player work. With good piano work, the player mechanism can perform at its best.
Work began with restoration of the keyframe, bottom board, and pedal trap work.
Bottom Board and Pedal Trapwork
When boring piano hammers, keeping chips away from the jig surface is a constant need. I was tired of clearing the debris with a hand-held air nozzle. $36 in parts from Amazon helped me to create a nice solution. The heart of the solution is a 12V DC solenoid that is controlled by a magnetic switch. The magnetic switch closes when the drill press quill descends. Like a lot of shop improvements, I didn’t get payback in the first use, but the drilling process is much more efficient when using this new fixture.
Here’s the parts list:
While installing pedals on a 90 year old upright piano, I had the opportunity to upgrade materials, and have a little fun at the lathe. The old pivot system employed a hardwood dowel bushing in a cast iron bracket. The system was likely a good one for the first 30 years, but with wear, it became floppy and noisy, and broken. I chose to fabricate new bushings to be used in the old brackets using UHMW (ultra high molecular weight polyethylene) rod. UHMW is ideal for this application, since it is self-lubricating. For someone who doesn’t do a lot of lathe work, it presented a bit of a creative challenge, and I’m pleased with the result. I’m sure it will be serviceable for many years, and earns a lifetime guarantee.
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.