Thanks David. This is a rather mundane question, but what should I fill the old capstan hole with? High quality wood filler? Epoxy of some sort? Or a dowel? On Sun, Feb 8, 2009 at 12:06 AM, David C. Stanwood <stanwood at tiac.net>wrote: > Noah, > > Do mockups with the capstan moved in towards the balance rail. Try finding > a position were the key dip is more normal like 10mm and the blow like 45mm. > This should lighten things up..... you might have to cut the heels off and > use new ones that satisfy the magic line... > > David Stanwood > > > First, forgive me if this query is too long and arduous. I should >> perhaps just hire an experienced Tech for a couple hours to come and help me >> with this, but I'm trying to wade through it alone: >> >> In checking the Geometry of this 1906 Spector & Sons Baby Grand, my >> "magic" line seems to be much "mundane." The line runs maybe 1/8" above the >> center of the capstan, rather than through the middle of it; it doesn't even >> run through the center of the capstan top - but slightly above. It's a >> little hard taking this reading however since there's a small wood >> stabilizing foot (also the square wippen rail) that gets in the way of my >> string, so that I have to hold the string about 7/8" away from the key and >> carefully follow the line of the string with my whole head so as to not >> distort the view. Does that make sense? >> >> When I push the keys down 5 mm, the hammer rises average 35 mm. This >> gives me an MAR (Mechanical Action Ratio) of 6.75. That is way too high no? >> Is 5:1 ratio ideal? Perhaps this high MAR would explain why this piano >> "plays like a truck." According to my calculations using John Dorr's Article >> in the November 2008 Journal, I would need a 48.4 mm Hammer Blow to make my >> 8 mm key dip work (I didn't even know anyone made actions with such low >> keydips.) However, my hammer blow if I remember is (was, before i messed >> around with the Wippen Rail) only 47 mm - and that's with the hammers >> resting on the the hammer rest rail flet. (There is room to lower that >> Hammer Rest Rail however if I choose to later). >> >> I have no idea when this was last regulated - maybe decades ago. >> I moved the Wippen Rail forward about 3 mm. From looking at the magic >> line again, it looks like if I moved the capstans forward the same amount it >> would become less mundane and more magical. >> >> Now for My Question: Should I unscrew all the Capstans, plug the holes >> and move them forward? >> >> Or, is there another way to change the magic line that significantly? >> >> Also, I'd like to get more into the Stanwood Touchweight, and was about >> to start taking measurements but saw that it was a waste of time with the >> magic line so out. The only measurements I've taken thus far then are Down >> and Up weight, which averaged 61 DW and 23 UP. I mention this so as to give >> more information, but also I guess I have one more question: I need new >> hammers. These shanks have the sloping knuckle that's built into the shank. >> Does it matter much which Centerpin-to-Knuckle Spread I get? In drawing a >> line up from the back of the jack, i got an 18 mm and 19 mm spread on the >> two I measured. But that's the back of the jack, so that's not the correct >> measurement anyway I think. Plus of course that assumes that the piano was >> regulated correctly, which it probably isn't. I was thinking of ordering the >> 17 mm Spread. >> >> Thanks to anyone willing to help! >> > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech_ptg.org/attachments/20090208/185cb7aa/attachment.html>
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