Al, Front rail adjustment is interesting, and I'd like to consider it, but I don't quite understand it. I'm assuming you have bedded the action in the piano first. This would have included adjusting the balance rail glide bolts such that they were protruding some small amount below the flat plane of the keyframe. If my assumption is correct, this means that when the keyframe is on your bench, glide bolts in their piano bedded positions, frame clamped all around, sitting on your flat bench plane, that the keyframe is probably flexed up a bit at the balance rail. If I'm correct, by adjusting the front rail, which you can only adjust upwards, that this allows you to lower the balance rail relative position, but not raise it. It also allows you to follow the contour of the front of the keybed which may be cambered. As I write this I think I'm starting to follow your reasoning.... My approach, which as I said, I'm not happy with, made the adjustment at the balance rail. My bench top consists of a 1-3/4" commercial solid core door with with 1/8" mahogany veneer both sides (got 10 of 'em almost free when I built my shop). My staightedges tell me its a pretty decent plane. I relieved an 1/8" deep x 3" wide trough under the balance rail and installed some carriage bolts in the trough, head up, as adjusters. Jim I I installed 5 glide bolts upside down (similar to some Baldwin grands) on > the front of my bench (which is a Steinway B keybed) and use them to make > the adjustments. The way I set them up is to use action springs to hold the > action firm to the bench, then I raise and lower the front glides in the > bench by checking the center glides as you do when bedding the action, > making adjustment to the front glides bolts 'til you get it right. Then I > check the key dip to be sure it's correct. Works great. I don't need to make > many adjustments in the piano after that. > > Al G > > > >> >> -- grandpianosolutions.com (under construction) Shirley, MA (978) 425-9026 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20090730/28d1c0ef/attachment.htm>
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