Good evening to all friends, after having restored the entire action of an old upright piano, center pins, hammer felt, button, escapement etc. etc., regulated hammer-string distance 4.5 cm, key dip 10 mm, escapement 3 mm, let-off 1.5 cm etc. etc., I find a problem that I cannot solve.. pressing the key, upon its release halfway through the stroke, if I try to press it down again, the key jams as if the repetition lever is being blocked by the hammer rest because it slips too far down and I find the hammer at rest and the pusher cannot restart the hammer unless I release the key completely. I have tried various adjustments but nothing changes. .this happens across the entire keyboard. Greetings to all.
Try to give more play to the escapement upright. With the mechanics stationary, hammers in the rest position on the hammer rest felt, the upright must move back under the cap/nut freely (otherwise act by slightly screwing the pilots). Then also check the efficiency of the escapement upright springs. Also check that the friction of the uprights is not excessive (1-2 grams)
Thank you maestro, always ready and quick to respond. In fact, I find the matter a bit anomalous because I have already done all these tests. Anyway, I will try again to adjust everything as advised. In other uprights, I had the same problem and always resolved it without difficulty; perhaps something is escaping me and I cannot resolve it. When you say to check the upright spring, in this case do you advise giving it a bit more tension?
Yes, of course, check the upright pin as well. However, I believe it depends on the lack of play in the uprights under the nuts when they are in the resting position. Try touching the uprights again and making them come out freely from the nut when everything is in the resting position. If this does not happen, then screw the pilots in until they are free but without any backlash.
