<html> <head> <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"> </head> <body bgcolor="#FFFFFF" text="#000000"> Since 1988  I've tuned the old upright of a local GP, now retired. Early on, I regulated for lost motion, only to find next time, that the hammers were, unevely, lifted off the rail.  So I regulated the screws back down, leaving the hammers on the rail, without lost motion. Only to find, next time, that there was lots of lost motion.  It seemed apparent that the capstan screws were moving, cyclically, up and down in the keysticks. The problem was not the back rail, because if it was shifting, then the movement of the hammers off the rest rail would be more even.  I eventually fitted slightly thicker screws, hoping that the added friction would solve the problem. It didn't! I was at the piano today, and took the pics attached. Why do these screws work up and down like this? Best regards, David. <a class="moz-txt-link-abbreviated" href="http://www.davidboyce.co.uk">www.davidboyce.co.uk</a> </body> </html>