[CAUT] Underlever Felt

[Bob Hull]

On the SD 10 here the underlever pinning was checked and found to be stiff.  Repinning helped and improved damper function a good amount.

We haven't removed the tray and adjusted the springs yet, however we noticed that there are springs only in the bass.  The weight of the underlevers in the tenor are approx. 15 grams.  I think I read in a set of Renner back action instructions that the grams was supposed to be around 28 in the tenor.

the weight of the whole underlever by itself is only 22 grams.  Either weight will have to be added to the underlever or a spring.  But if it worked originally  without it, I hate to add it.

Bob Hull



----- Original Message ----
From: David Ilvedson <ilvey at sbcglobal.net>
To: caut at ptg.org
Sent: Monday, August 24, 2009 6:55:09 PM
Subject: Re: [CAUT] Underlever Felt

Got it...my original reply to your post was how you adjusted damper springs.  I understood removing the underlever system to adjust springs, but was unclear on what you mean't by finessing individually on re-installation...was that something to do with the springs again?  I understand now...all those things you listed are imperative for good dampening...

I still have a problem determining which way and how to bend the wire for fit in the top flange...do you see something in particular that tells you I need to bend the wire towards the bass?  The first bend is above the top flange?

David Ilvedson, RPT
Pacifica, CA  94044

----- Original message ----------------------------------------
From: "Jon Page" <jonpage at comcast.net>
To: caut at ptg.org
Received: 8/24/2009 4:40:55 PM
Subject: Re: [CAUT] Underlever Felt


>>>"can be finessed individually on reinstallation"
>>>
>>What does that mean...


>Each damper fitted to the strings with more precision
>than some factories allow. It starts with a firm, frictionless
>bushing hold and then bending the wire such that the
>damper moves in a straight, vertical path with the wire
>also falling into the top flange unencumbered by
>misalignment causing stress on the underlever and
>guide rail bushings.

>Having to rely on side pressure on the bushings to dampen
>the wire is counter productive. Time saving maybe but not
>beneficial in the long run or for performance.

>Having the head centered over the unison.

>Cutting the center slice deeper on trichords to allow full
>insertion/contact and a slight billowing. Cutting the trichord felt
>just below the strings and trimming the leading edges of the
>felt to reduce drag.

>Trimming the outside lower corners of the singles if they are
>showing signs of being pressed out to rub against the
>adjacent damper felt.

>Before all this was cutting the felt, graduating the length smaller
>as you go up the scale and gluing in place. Also graduated
>assist spring tension.

>It's all rather simple if you just take the time and price the job accordingly.

>Then you could also just install the dampers in a wholesale manner
>and hope for the best.

>Regards,

>Jon Page