[CAUT] F..riction (rep spring)

[David Stanwood]

Thanks Don,

I think I speak for a multitude when I say it would be nice not to 
have to repin every set of reps we get!  Do/can manufacturers 
actually know/publish the hammer weight limits associated with their 
spring size/design...!??   I ran into this problem early in the game 
while going down the super light hammer road...  didn't figure out 
the reason until years later.... like last year... when I tried 
regulating a rep with a very heavy spring material made in a rather 
large country to the west of Japan.   Adding two grams to the medium 
hammer weight solved the problem... also replacing with a much 
lighter spring wire worked.

regards,

David S

>Good point, David.
>
>This also occurs when the spring slot is gummed up, or the spring 
>has been incorrectly bent so that the spring contacts too close to 
>the rep lever center pin.
>
>But I also believe that a fairly tight rep lever bushing is 
>beneficial to action performance, within reason.  Measuring 4 grams 
>at the drop screw pad is a pretty tight fit and seems to give good 
>performance.   I have had good luck solving repetition and spring 
>return issues this way when I found 0-1 grams resistance in the 
>repetition lever center.  Some advocate even higher friction than 
>this, but I agree also that this can degrade smooth pianissimo 
>playing.
>
>Don Mannino
>
>-----Original Message-----
>From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf 
>Of David Stanwood
>Sent: Wednesday, December 01, 2010 8:55 AM
>To: caut at ptg.org
>Subject: Re: [CAUT] F..riction (rep spring)
>
>Fred and Alan,
>
>This could be another thread but here's my 2 cents...  We find 
>ourselves in situations sometimes when the rep spring lifts the 
>hammer in a nice controlled motion upon release from the back check 
>yet the jack still cannot be made to return under the knuckle... 
>even to the point were the repetition lever height adjustment button 
>is
>completely off it's rest pad to no avail.   Repinning the rep lever
>can sometimes make this symptom disappear.  Is this what you're 
>referring to Fred?
>
>My take on it is that when this happens it indicates that the wire 
>size of the repetition spring is to high so that when it even just 
>starts to work it's already too tight after going just a little way 
>into its arc, so it's kind of on the edge of starting to work..
>switching to a smaller spring size will solve to problem or going 
>with a heavier hammer...
>
>When the hammer weight and spring size is matched the rep lever will 
>work with low friction.
>
>David Stanwood
>
>>Fred,
>>
>>By "pinning those reps heavy" do you mean tighter pinning? Can you put
>>a number on it, as in what do you aim for in pinning rep levers?
>>I know that some go for pinning reps at about 8g, but on nearly every
>>new set of wips I've encountered the reps are pinned in the 0-1g range,
>>at least when I get them. I don't know what the manufacturer aims for.
>>
>>Thanks.
>>
>>Alan
>>
>>
>>Certainly pinning those reps heavy makes it easy from the technician's
>>point of view, to set springs so the hammer rises nicely in our
>>artificial emulation. And I have found situations where heavier pinning
>>was necessary to get the jack to re-set under the knuckle consistently.