Hi again all.  Well, the piano is being used this afternoon, so Monday I'll get in there and look at everything again. Good hints from everyone.  Thank you! I meant to say move the caps forward (toward me) not back! :>O   Other things I didn't check at last glance was size of the leads, wear (cupping) on the cuhions, or knuckle to flange center measurements.  My bad!  To get a better idea of the age of the parts, when did Renner start using rep spring screw?  Or did they always have it?  They look so new I have to wonder if they had been replaced at one time. The more precise year for the piano is 1979... I'll report to all on Monday! Enjoy. PW <table width=100%> <tr valign=top> <td width=40%>Fred Sturm <fssturm@unm.edu> Sent by: caut-bounces@ptg.org 09/21/2007 12:27 PM <table border> <tr valign=top> <td bgcolor=white> <div align=center>Please respond to College and University Technicians <caut@ptg.org></div></table> <td width=59%> <table width=100%> <tr valign=top> <td> <div align=right>To</div> <td>College and University Technicians <caut@ptg.org> <tr valign=top> <td> <div align=right>cc</div> <td> <tr valign=top> <td> <div align=right>Subject</div> <td>Re: [CAUT] moving capstans question</table> <table> <tr valign=top> <td> <td></table> </table> Hi Paul, What you are describing is a convergence issue, rather than a leverage issue (though there may be leverage issues as well). The line from balance hole bottom to wipp center is the "line of convergence" and you want the top of the capstan/bottom of the wipp to be on the line when the key is halfway through a keystroke. This mostly affects friction, how much the capstan and wipp cushion felt rub back and forth against each other. The least amount will occur when you have it set up as I described. It usually doesn't have that much of a noticeable affect on touch unless the capstans and wipp cushions are "gunked up." It will affect wear, how long the cushion felt lasts and how soon it becomes badly cupped. If this is enough of a problem to address, the best way to address it is with wipp heel changes. For what you describe, you want a thinner wipp heel. Picture it like this: hold everything in place, and shave X amount off the bottom of the wipp heel. You will now have to raise the capstan to meet it. Hence, the contact between capstan and wipp cushion will be higher relative to the line of convergence. Moving the capstan line will affect convergence, but only "by the way." Let's be clear what we mean by back and forward: back, toward the back of the key, forward toward the front of the key and the player. Moving back will make the capstan lower relative to the line of convergence. Moving it forward will make it higher. (The line of convergence is slanted relative to the top of the key). But the main effect is on leverage. Moving the capstan back means higher ratio, and heavier touch (all other things being equal), and means less keydip for the same blow. Moving forward does the opposite: lower ratio, lighter touch, and more keydip for the same blow. Raising or lowering the stack has a lot of side effects, especially having to do with hammer bore distance and how squarely the hammer hits the string. You don't want to go there unless you are able to think of all the effects. Well, raising it is simple to experiment with, just a few shims you can easily remove, and not a lot of time lost. And you can consider just shimming the back legs, which you can do more of without causing problems getting the action assembly in and out under the pinblock. But it does have other regulation effects besides just the convergence thing. I guess I would start by questioning whether convergence is the issue here that is making people hate the piano. The most likely problem is new heavy hammers on old knuckle geometry (16 mm or so vs. 17 mm or so current specs). In that case, best solution is probably moving the knuckles, whether that means new shanks with different knuckle placement, or cutting new slots on the old and installing new knuckles - which requires specialty jigs. Regards, Fred Sturm University of New Mexico <a href=mailto:fssturm@unm.edu>fssturm@unm.edu</a> On Sep 21, 2007, at 8:34 AM, Paul T Williams wrote: Hi List! Happy Friday! I am working on a 70's Sty B with a horrible action geometry problem. All the students and the professor hate playing it and I don't blame them! The line from key balance hole to wip has the capstan way too low making the DW close to 70g throughout.  It has a renner action and hammers.  the wips and capstans are such that I could relocate the capstans back by about 3-4mm.  Would that make a big enough difference in the DW? It won't affect the line.  I looked at raising the stack, but there isn't enough room to raise it more than 1-2mm.  Should I try both? Also, is the measurement in Steinways made from center of balance rail hole on the top of the key, or from the back of the key?  This is a new endeavor for me and I don't want to make things worse. Still green in Lincoln, Paul