<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <body bgcolor="#FFFFFF">   "Bradley M. Snook" wrote: <blockquote TYPE=CITE><style></style> When I do concert level regulation, I try and get key dip, aftertouch, letoff, and blow distance as even as possible (in that order). As a general rule, I try to maintain evenness in aftertouch and key dip, which forces me to distribute the majority of the inaccuracies between the blow distance and the letoff. Every once in a while I come across a note where something in the action geometry is obviously wrong (e.g. to get everything else correct, the blow distance would need to be in excess of 1/8" higher/lower than the rest of the hammer line). What do I do to fix this problem?  Bradley M. Snook Graduate Student in Piano Technology (M.Mus) Rice University, Shepherd School of Music</blockquote> Hi there Bradley.. long time no hear ! What do you do to fix the problem eh ??? First I suppose you have to find out what the problem is. And there are obviously lots of puzzles that daily pop up in front of us.. some easy to figure some not. The kind of problems you zoom in on above are often enough due to inconsistancies in dimension or placement of action parts. I just ran into a problem today that caused both a weird let off and drop situation for one note, and about 6 grams of extra BW. Turned out that someone had replaced a hammershank that was origionally equipped with a knuckle 17 mm from the center pin with one 15 mm from it.. and to boot it was a bit smaller around as well. Definantly not done conciously me thinks. :)  Same piano just threw me for a loop because of the way the balance rail pin holes were drilled... took me a while to figure it out but as it turned out the keys couldnt move past perpendicular to the balance rail pins... the back wall of the hole was stoping them... real inconsistant too.. made for a very strange last 2mm of key dip with all that entails.... so its not always strictly geometry that can cause such things. In anycase.. a few things I look at that help find and achieve aftertouch consistancy 1. I look the the whippen height line... i.e. sight down the line of whippen heels resting on the capstans. Ideally they should all be exactly the same height. 2. The jack tops should ideally be all the exact same distance from the etched mark on the top rep lever. In the same breath use this sameness to help insure knuckle position consistancy. 3. I like to first make sure that I have sufficient rep spring strength and insure that the jack top just slips back under the knuckle when you manually engage and let go of the jack tender. Then I run through letoff making them as even as I can get them. Then I lift up the hammer out of the way and watch the top of the jack as I bring the whippen up to the drop button. If the jack top doesnt start moving forward at the exact same moment the drop screw engages.. then I change drop until upwards and outwards movement of the jack top start simultaneously. If all thats correct then the only thing left is key dip. If after that, there is something noticably wrong then I start looking for things like I mentioned above. BW can be a good diagnostic tool for some of this by the way. But you have to know what the actions SW ratio is to use that. Lots of stuff can get into this picture to be sure, and I've only covered a bit of it. Looking forward to the other responses Cheers RicB       -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway <A HREF="mailto:rbrekne@broadpark.no">mailto:rbrekne@broadpark.no</A> <A HREF="http://home.broadpark.no/~rbrekne/ricmain.html">http://home.broadpark.no/~rbrekne/ricmain.html</A> <A HREF="http://www.hf.uib.no/grieg/personer/cv_RB.html">http://www.hf.uib.no/grieg/personer/cv_RB.html</A>   </body> </html>