I cut the mortises with a fence on the bandsaw.
Since they're hard they work sort of like guides for sawing. My keyboard, as well as Davies', has one of the main parts of the action glued onto the keys.How to Make A Piano Harmonium from Cardboard
Greasetattoo 7 years ago on Introduction. The keys are finished to their final shape.
In order for the regulation to be durable, and to reduce the amount of noise the keyframe needs to be fit, or bedded to the piano in the exact position it will occupy. For what it is it plays fine, but it's not like a modern piano - the action is the old English kind you can see in the animation on this page. The action has to be adjusted closer to the piano than it was on the bench, but it involves the same things.
This is advisable only if your piano has pure ivory keys.
Milk is also a fantastic choice. I reused old two-piece ivory from an old piano, but this makes it more difficult because each pair has already been trimmed, levelled and shaped together for the exact key they were on originally, and like the ones I used they are often discolored, worn and damaged.
My keys were all front heavy but in this kind of action they need to be back heavy by as much as 15 grams and return to rest by themselves so that they repeat and have the right amount of resistance, and one of the only places to put weights would have been inaccessible since it's directly below one of the action rails.
The front mortises have to be made oblong with perfectly parallel sides, and Bluthner suggested using a broach but didn't describe it. The ideal ratio is one part of vinegar in 4 parts of water. Ivory is extremely porous by nature.
The keyboard's position is much less critical in uprights than it is in squares and grands where it affects the sound and function of the piano. The finished dimensions of my keyplank were a little less than 600mm wide at the front, about 37cm long and and 18mm at its thickest. The treble stretcher is longest and is about 40cm long.
I checked the resulting weights at the front with a couple uniformly spaced sample weights for four different pairs of neighboring natural and sharp keys and just drew lines connecting the positions I had marked out. Too hard for me. Using mayonnaise and yoghurt to clean ivory keys Image Courtesy of Metro News Although this may sound weird but the acidity caused by the bacteria present in yoghurt and mayonnaise helps to bleach the ivory in a gentle way.
I chucked it in a benchtop drill press and kept the mortises aligned by using a fence and locking the spindle. The wood they're made of has to be dry, straight grained and free of knots, as well as stable with changes in humidity and relatively strong and easy to work.
Be sure to use normal, plain white toothpaste only. I planed the edges as straight and flat as I could to prevent introducing any stresses the from gluing or clamping. I think at least in old factories finishers were the most experienced and skilled workers, and sometimes they signed or stamped their name on top of one of the keys, but in small letters and somewhere not visible when the piano is all assembed.
A special step drill bit like Audsley described would be more efficient. You have to make sure the keys are all the way down on the pins, and for a final regulation the paper punchings are supposed to be placed underneath the cloth ones.