Installing New Hammers & Butts in an Upright Piano

The project described below was recently completed on an 1888 Everett Upright piano. The original action was very noisy due to many loose center pins, and the hammers were badly worn. The owner asked us to rebuild the action and to return the piano to good playing condition. We decided to install new hammers, shanks, butts, wippens, and damper levers, to rebush the keys, and to conduct a complete regulation and tuning.

1 – In rebuilding the action of this piano, we installed new damper levers and pads, hammers, shanks, butts, and wippens. We used the original stickers, and we rebushed the keys.

2 – We first removed all action parts except the hammers, shanks, butts, and the hammer rail.

3 – With the "stripped" action in place in the piano, we marked the "striking point" across the strings with masking tape, drilled and installed "sample" hammers using the current hammers as guides, at the beginning and end of each section. We "dry fitted" the shanks of these sample hammers in the butts with paper shims so that we could remove them as needed for hanging the others in our jig.

4 – We used our special Renner hammer drilling jig for drilling the hammer heads.

5 – We installed new hammer butts.

6 – Using "dry-fitted" shanks, we traveled each butt, correcting the direction of those which didn't direct the shanks straight toward the strings. We marked the front of each shank to ensure installing them in the same direction after hammers were hung on them.

7 – Using our wall-mounted knurler, we knurled one end of each shank--the end on which the hammer head would next be mounted.

8 – Items used in the hammer installation process: a hand drill for angle corrections, liquid hide glue, a heater for quick adjustments after glue joints are dry, a "glue dispenser," a scoring tool for excess glue, a pencil.

9 – Using the "Spurlock Upright Hammer Hanging Jig," we glued hammer heads to the shanks, clamping one section at a time until dry--a guide at each end to ensure consistent placement of the hammer striking points. With a Japanese saw, we cut the shank ends so all shanks were the same length as the guides.

10 – Beginning with hammer #88, we glued the shanks into the butts. Before the glue had dried completely, we arranged the hammers at the same heights as the guide hammers, and we aligned the hammers to the strings either by moving strings, or by spacing hammers, or by moving the butts.

11 – For the lowest treble hammers, we cut the shanks at longer lengths in order to provide room for longer dampers.

12 – After all hammers and butts were installed we checked hammer-to-string alignment again as well as consistent, even hammer spacing and height above the hammer rail as well as straight travel to the striking point on the strings. Corrections were made where necessary.