Grand Piano Keyboard: Replacing Swollen Lead Weights

This is not from your piano, Lex. This gallery documents a similar repair to the one we're doing on your piano. This piano belonged to Mark Blows, a Beethoven specialist, and composer.

At the far end of the keys you can see some weights, ranging from 40 to 70 grams. Usually the lowest A can be depressed or 'played' by a weight of 52g, and the highest C, having a smaller, lighter hammer can be set in motion if you place only 48g on it.
lead 01
The key is being held over the jaws of a vice.  There are 3 pieces of swollen lead in this key. A press-punch is pushing one of the lead pieces out, it will roll down the inclined wooden strip and land in the container below.
lead 04

lead 06
The same, in greater detail.
lead 07
It is possible to melt down the old lead weights, but it is better to use new uncontaminated lead. We recycle the old ones.
lead 08
Here you can see the split in the side of the key. At least 30 keys were split, and this has meant quite a bit of repair.
lead 09

lead 10
Another split key. All the first 30 keys were damaged like this; the keys are short and the lead is bunched close on each of them, meaning that the wood is overstressed.
lead 11
This sharp key had a particularly swollen lead, which did not give in easily.  The timber looks a little worse for wear, but in fact the pieces went together like a jigsaw, and repaired quite well.
lead 14
At the end of the lead removal!
lead 15
One of the split keys. On a larger piano, the split might be longer, and the wood can be repaired by syringing glue into the split and clamping it from top to bottom.In this case the key will be reinforced by the use of marine glue which permeates the wood.
lead 17
At the far end of the room the keyboard with all the keys which are ready so far. In the foreground about 20 of the split keys, clamped on their sides, about to have the marine glue poured into the holes.
lead 18
Next morning the glue has hardened, so we've taken off the clamps, and the excess glue will be trimmed, and the keys then put back on the keyframe, ready for the next process, drilling new holes for the new lead inserts.
lead 20
The next lot of keys to be plugged with glue. The long chalk mark on each key is to indicate a split in the key.
lead 21
Close-up of a split key
lead 22
... and a close-up of a sharp with brittle wood.  The factory method here could have been better. Instead of one large hole with a small hole right beside it, weakening the timber, the smaller hole could have been a larger one as well, but separated by a lot more, achieving the same leverage.
lead 23
The marine glue seeps and permeates; we go to some trouble to produce little wooden caps which are glued on one side to prevent the marine glue from escaping when the key is clamped on its side.
lead 24

lead 25

lead 26

lead 28

lead 29

lead 30

lead 30a
The lead available in the local supply place is tapered to fit different diametres of hole. In the end the result is unsatisfactory, so we cast our own. Very simple: a camp stove and an old saucepan. Each cast produces a dozen leads. It is time-consuming. Lead can be bought from Germany, but the freight adds a fair bit to the cost
lead 31
I do the casting outdoors, because of the fumes; as long as the saucepan is low enough the fumes don't defy gravity; fortunately there was a good breeze blowing through last night, so I didn't have to wear the gas mask.
lead 32
By the way, click on any photo, and it will open up larger. You'll need to use your browser's back-button to get back to the gallery.  More photos will be added later.
lead 33
 
A record of the steps involved in removing the swollen lead from the Marshall & Rose Grand keyboard. For more
 
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