Thanks Dave, > I would guess that the hammers are bored too short or worn--check again. ***** The hammers are new and I have just bored them and they are correct based on string height and hammer flange center height - no need to recheck something that I have already rechecked at least two dozen times. They are light but I have a 5 pound roll of lead wire to help bolster their mass and intend to use it. , play with the spread a bit and see what you can do in terms of changing > the dip/blow balance, ***** At 113mm I suppose this normal number may be excessive for this action. I have not played with this yet. otherwise, on this piano power is probably not that > much of an issue and redesign costs might be prohibitive. Keep it simple. *****This piano is my spec piano and has a new custom board, redesigned scale and bridge. As with so many aspects of novice rebuilding it is not easy to see difficult issues before they manifest. I am not opposed to action redesign but would like to make this one work. It is my education so the expense is worth it to me. Gene > > > David Love > www.davidlovepianos.com > > -----Original Message----- > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On > Behalf > Of Gene Nelson > Sent: Friday, March 13, 2009 4:52 PM > To: pianotech at ptg.org > Subject: Re: [pianotech] high leverage action > > > >> Hmmm... I think we'll have to be a bit more specific then that. A 10 >> gram > >> strike weight in the top low strike weight zone equates to something >> around hammer number 5. A weight of 5 at key 88 is perhaps a quarter >> zone > >> higher... that means you have really low hammer weight if this is >> reflective. > ***** I will probably push the hammers up to number 6. As I said, I have > not > > done any corrective hammer leading yet. > > Front weights... assuming we are balancing the >> same notes you mentioned for hammer weights then you have an action >> ratio > >> of 6.2 in the bass ranging to 7.8 in the treble. Kind of wild... but >> suffice to say you have a high action ratio... which fits at least your >> KR > >> and Knuckle configuration. Without more specifics this is just ball >> park. > >> I'd ask for at least 7-8 samples of SW, FW, BW, and KR along with your >> WW > >> to get a more accurate picture of your situation... say all C's but I >> think its safe to say you have a pretty high action ratio....no matter >> which way you look at it. > > ******My samples were not all C's but they are all naturals, first and > last > in each section. - here it is: > note# SW FW BW KR WW > 1 10 30.1 41.5 .55 16.4 > 25 10 26.7 42.5 .52 16.4 > 27 9.3 23.8 39.5 .54 16.4 > 45 8.4 15.5 44 .54 16.4 > 47 8.7 16.6 42.5 .53 16.4 > 66 6.8 7.7 42.5 .54 16.4 > 68 6.5 6.5 41.5 .54 16.4 > 88 5.0 6.8 36.5 .53 16.4 > Note that the WW value is the same because it is the average - the range > was > > from 15.9 to 17.2 > >> >> Why you end up with such a short blow distance and deep key dip to get >> any > >> aftertouch is a good question if the above is close to the truth of the >> matter. A short bore length would force you to raise the shank closer to >> the strings... ie raise the underlever (whippen) which should not require >> a deep key dip to get aftertouch. A long one would keep your shank just >> off the rest cushion at a shorter blow distance... and perhaps fit the >> condition of a high action ratio thats heavy, has keep key dip and short >> blow with minimum aftertouch. But if you are certain about bore length >> being at String height - hammer shank center height then something is not >> quite right with this whole picture.... grin.. or its just so late over >> here that I've got things backasswards again.... wouldnt be the first >> time. :) > ****I am absolutely certain that the bore distances are based on String > height - hammer shank center height. >> >> As far as minimum 44 mm. I think thats about as short a blow as you can >> allow for without sacrificing too much power. Usually you find somewhere >> between 45 and 49... sometimes 44... sometimes 50.... rarely outside that >> because of what implications it has for the rest of action regulation >> specs. We have this ideal of about 10 mm key dip, and about 1.5 to 2.5 >> mm > >> letoff... which more or less dictates blow for any given amount of >> aftertouch. It all adds up usually to somewhere between 44 and 50 for >> blow. > **** I measured the height of the sharp blocks to get an idea of maximum > key > > dip. Not that I like that much necessarily. > > Gene > >> >> Cheers >> RicB >> >> >>> >/ What are your Hammer Strike weights >>> /*****10 in the bass and 5 in the treble - no corrective weighting >>> action > >>> taken yet. >>> >>> and key Front Weights ? >>> ***** >>> 30 in the bass and 6.8 in the treble >>> >>> Your dip >>> >/ and blow say low ratio but your KR and knuckle distance says high. >>> >How >>> />/ much aftertouch are you getting with things as they are... >>> /***** about 1.5mm or slightly less. >>> >>> how far out >>> >/ from under the knuckle does the jack move ? >>> /*****Just enough for drop and aftertouch to happen. >>> >/ >>> />/ 41 mm is on the short end of the stick to be sure. I usually dont >>> see />/ under 44 and never allow for less when redoing an action. >>> /***** Do you have a reason for maintaining 44mm or greater blow >>> distance? >>> >>> Regards, >>> Gene >>> >/ >>> />/ Cheers >>> />/ RicB >>> />/ >>> />/ >>> />/ Hello list, >>> />/ Thought that I would seek comments on an action with high >>> leverage. >>> />/ Key dip is 10.5mm and blow distance is 41mm. >>> />/ The touchweights are in the low 50's down and low 30's up. >>> />/ Knuckle spread 16.5mm >>> />/ Key ratio is 1.81 >>> />/ Action spread is 113mm and is adjustable. >>> />/ Any more dip will make the sharps about level with the naturals >>> when >>> />/ depressed. The feel of the samples are acceptable. Seems that >>> 41mm >>> />/ blow distance is short - but is it too short? Maybe some loss of >>> />/ power? Is there a down side to this action? Any corrective >>> />/ suggestions? It is in the sampling - disassembled stage. >>> />/ Thanks, >>> />/ Gene >>> />/ >>> />/ >>> />/ / >> > > >
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