Greetings,
I recently was called upon to repair an old upright piano that had a large
crack in the bottom board (the board to which the pedals and trapwork are
attached). The bottom board was badly damaged, and needed to be replaced.
I thought it would be useful to have a step-by-step list of procedures to
follow when I need to do this repair. This information may be useful to
you as well.
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Making a New Bottom Board for an Upright Piano
By David A. Vanderhoofven, RPT
October 16, 2001
Purpose:
The purpose of this procedure is to make a new bottom board for an upright
piano when necessary. The pedals of the piano are attached to the bottom
board, and if this board is cracked, broken or otherwise damaged, the
pedals may not function properly. Also, if this board is damaged (cracked,
stripped out screws, etc.), the pedals may make unwanted excessive noise or
squeaks. This is intended to be a step by step explanation of the process
I used when I recently made a new bottom board for an upright piano.
Tools and Supplies Needed:
* Table saw or Skil-Saw
* Jointer
* Biscuit Jointer and biscuits (or doweling jig and wooden dowel pins )
* 1/2 electric drill and assorted drill bits and driver bits
* Router and assorted router bits
* Palm sander and assorted grits of sandpaper
* Tape measure
* Assorted clamps
* Assorted Phillips and flat blade screw drivers
* Sharpened cabinet scraper or chisel
* Piano Tilter
* Spray can of flat black lacquer
* Spray can of clear gloss lacquer
* An assortment of wood screws
* Wood glue
* Assorted pieces of bushing cloth, felt and leather
* Leather gloves
* Protective Eye glasses
* Respirator face mask
* Shop apron - to protect your clothes
* Vacuum cleaner
* Cleaning cloths
* VJ Lube or Protek MPL
* Pedal Props
* Pedal bushings
* Pinblock plugs
* Wood to make the bottom board
(I used 3/4" thick poplar, but another hardwood or cabinet quality
plywood would also be suitable.)
Shop Facilities:
The shop should be well lighted, have enough space so that the technician
can move around comfortably, and must have good ventilation. There must be
no open flames or other sources of a spark that might cause the lacquer
used to burn or explode. A spray booth or other draft free spraying area
is useful.
Procedure:
1. Remove lower front panel, and disengage and remove pedal rods
2. Lay piano on back using piano tilter
3. Remove screws holding bottom board in place
4. Remove bottom board
5. Measure dimensions of bottom board (thickness, length, width)
6. Cut new wood to dimensions of old board using table saw or skil saw.
If the old board is wider than the wood you have available, it may be
necessary to glue up several pieces of wood to get the necessary width. If
this is the case, the following steps apply.
A. Use jointer to get smooth edges on wood
B. Use biscuit jointer to cut slots for biscuits (or use electric
drill and dowelling jigs to drill holes for dowels)
C. Apply wood glue to both edges of the wood you are gluing together.
Apply glue to slots and biscuits (or apply glue to dowel holes and dowels)
D. Insert biscuits (or dowels) and clamp edges of boards together
E. Wipe off excess glue before it dries
F. Allow sufficient period of time for glue to cure (24 hours)
G. Use cabinet scraper or chisel to scrape off excess glue
(Of course, if you use plywood, steps A through G can be omitted)
H. Cut new board to dimensions of old board
I. Sand surface of wood smooth
7. Use router and router bit on new board to duplicate edge profile of old
board
8. Spray underside of board with several coats of flat black lacquer, and
spray upper side of board with several coats of clear gloss lacquer. Allow
sufficient time for lacquer to dry.
9. Repair stripped screw holes in underside of piano - epoxy pinblock
plugs in place.
10. Replace bushing cloth around each opening in kick board. Replace any
worn bushings in pedal assembly. Polish pedals and clear coat with brass
lacquer if desired. Polish and lubricate pedal pins (replace pedal pins if
necessary).
11. Position new board in place on underside of piano and clamp in place.
Drill pilot holes for screws to hold board in place. Drill through new
board into bottom of piano using drill bits of correct diameter, and drill
to appropriate depth (use depth stop if necessary. Use a countersink bit
so that screws will be flush with the wood surface. Install several wood
screws to hold bottom board in place.
12. Locate pedals in correct place and mark screw holes through the pedal
bracket holes. When in proper position, the pedals should not rub on
kickboard on either side, and the pedal horn should not rub on wood of
kickboard.
13. Remove bottom board and put on workbench. Drill holes for pedal
brackets, and install pedals and brackets.
14. Install bottom board, making sure to tighten all screws securely
15. Using piano tilter, return piano to vertical position
16. locate proper position for trapwork springs, mark and drill holes,
install trapwork and springs with wood screws
17. Install pedal dowels and regulate pedals. Check for squeaks
18. Reinstall lower front panel
Of course, if you have the piano tilted on it's back, this is an ideal time
to take care of any problems with the casters.
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Acknowledgements:
Thanks to Kevin Way, South West Missouri Player Piano Service, for
excellent help and advice and the use of his jointer and clamps.
***************************************************************
I hope that the above procedure is helpful to you. I am always looking for
a better and more effective way to do things. If you have a correction or
improvement to this procedure, please let me know. All errors are my own.
Permission is hereby granted to the Piano Technicians Guild to use this
information in any way that will benefit the piano industry.
Sincerely,
David A. Vanderhoofven, RPT
Joplin, Missouri
dkvander@joplin.com
http://www.janics.com/~dkvander/piano.html
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