I think the basic approach is as follows. First weigh off the entire action (up and down weight) with the wippen springs disconnected and chart it. Then set the FWs for uniform BW at about 9 grams heavier than your target (or for whatever amount you want to use the assist springs). After you do that you connect the springs and adjust the tension using the upweight as a guide. Thus if your BW without the springs attached yielded, say, a DW of 60 and an UW of 34 (BW = 47, 9 grams higher than your ultimate target of 38 grams) then with the springs attached and tensioned to 9 grams worth of reduction the new UW will be 25 grams (34 - 9 = 25). Set a 25 gram weight on the note and adjust the tension in the spring until it will lift 25 grams. No need to check the DW as it will change proportionately. You can also do this with the DW instead of the UW but I prefer the UW. It's an argument for adjustable wippen springs but then you have to use Tokiwa wippens. But this way you don't have to worry about varying friction from note to note. If the wippen assist springs don't go all the way to note 88 then in your weigh off you will have a jump in the FW's at that point. That will create a change in the inertia so you'll have to add the missing assist springs if you want to avoid that. David Love www.davidlovepianos.com From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Paul T Williams Sent: Monday, May 10, 2010 1:47 PM To: caut at ptg.org Subject: Re: [CAUT] Turbo wips/new info! I then disassembled it and took the stack off and looked, felt the wips with the hammers out of the way. Visually, some of the springs were a bit twisty and not a gentle curve as one might expect. Then, it was visual that the wips hang very unevenly. The twist is, that some higher hanging wips ( suggesting higher spring tension) with its' neighbor were either really close in DW to the neighbor that was correct, not at all, or opposite as you might think. It's very frustrating to be sure. Me thinks the springs have just been messed up by a former student tech. Perhaps a closer look at wip pinning might be in order? This was obviously something done by a previous student tech, or, a non named rebuilder from another state, not to be mentioned, who did this for us years ago....not Richard, of course! He's too good of a tech to have done this mess!!! :>) (REALLY!)....not too impressed with work from this other fellow....(other work around the school included)... If the springs are messed up, are the wips messed up as well? I don't see myself replacing all the springs.....too much time involved. Now what? Best, Paul From: David Stanwood <stanwood at tiac.net> To: caut at ptg.org Date: 05/10/2010 02:14 PM Subject: Re: [CAUT] Turbo wips _____ Hi Paul, The most conservative/classic approach is to adjust the springs on the bench with stack off and hammers up so that the wippens are hanging level on the springs. This creates a very even spring tension. Then weigh off with key leads normally for an even balance. In this scenario the springs will be working 9-10grams at the touchweight measuring point. Steinway Hamburg used this method in production for many years in the earlier part of the 20th century. What weigh off chart are you referring to? David Stanwood >Hi All, > >I'm having a problem with an older set of Renner Turbo Wips. I have >no idea how to get a consistant spring strength from note to note. > It's weighing off all over the place, but it doesn't seem >consistant with how the springs "feel". With the stack off and >hammers out of the way, some wips rise way up with a neighboring wip >hardly rising at all, but they "feel" different in springyness and >the weigh off chart says they're very close. All else is in good >regulation and pinning. On the whole, it's weighing off a bit >lighter than the professor likes, and wondering if I should just get >rid of the assisting springs? > >What say you? > >Thanks >Paul -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/caut.php/attachments/20100510/7cd9f546/attachment.htm>
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