Remove Cast Iron Plate
December 14, 2009
Now that the strings and tuning pins are out of the way, we can remove the cast iron plate. It is held in place by more than 50 large bolts and screws.
I use a chain hoist to lift the several hundred lb. plate out of the piano, being careful not to scrape or bump the mahogany cabinet.
Removing the plate exposes the 90-year-old pinblock. Our next task will be to remove it, and fashion a replacement.
The pinblock is dowelled, glued, and screwed into the piano on 3 sides. This picture shows the final stage of removal. With all the screws gone, and accessible dowels drilled out, the pinblock has been sawn into two parts, and wedges are used to separate the last glue joint.
Here's a close-up of the old pinblock and the material for the new one. Both are laminated from hard (sugar) maple. The plank on the right was manufactured in Wisconsin from locally harvested wood.
Colored chalk is used to mark the high spots, which are ground away until the surface mates solidly with the cast iron plate.
When the back edge and the top are well-mated to the plate, the other 3 sides are trimmed to fit into the piano case. There are many more holes to drill in the pinblock, but they won't be done until we're ready for final assembly.