[CAUT] Checking

[David Ilvedson]

I think you can go back to Bill Spurlock for a lot of this stuff...

David Ilvedson, RPT
Pacifica, CA  94044


----- Original message ----------------------------------------
From: "Tim Geinert" <geinert at drtel.net>
To: "College and University Technicians" <caut at ptg.org>
Received: 12/20/2006 3:25:56 PM
Subject: Re: [CAUT] Checking


>Alan,
>Thanks for the copy of the instructions.

>The first time I heard of raising the backchecks was from Scott Jones
>teaching at a regional seminar.  I think he also talked about using a snap
>ring pliers.  Kevin Stock, also with S&S for a time, had a modified snap
>ring pliers with a slot cut out for the wire.  He would just lift them, then
>even them out.  I think that's because he knew what he was doing
>intuitively.  It was Roger Jolly that I first heard put some numbers which I
>need with the idea;.... tail arc radius at 1/2 the hammer hanging distance
>(usually right around 2 1/2), shank intersecting roughly the top 1/3 of the
>backcheck (this does not need to be fussed with if the hammer line gets
>raised from filing or whatever), and the backcheck angled back 18 degress
>from vertical (pretty similar to the 68 or 70 degrees you work from, just
>different point of reference and 4 deg. different).  I always enjoy hearing
>the different approaches to the same thing, because not all things work the
>same for everyone, (not wrong, just different) and it is also good to get
>something reaffirmed by a seperate source.    A different perspective can
>turn the light bulb on.

>Tim G


>----- Original Message ----- 
>From: "Alan McCoy" <amccoy at mail.ewu.edu>
>To: <caut at ptg.org>
>Sent: Wednesday, December 20, 2006 2:46 PM
>Subject: [CAUT] Checking


>> Hi folks,
>>
>> Regarding Wim's thread. Just finished working over a 14 yr old GH1 with
>> poor
>> tenor checking. Tails digging into the backchecks, borderline-too-strong
>> rep
>> springs, backchecks at about 80 degrees, tails glazed, tails have a
>> S&S-type
>> hump and sharp bottom edge. Tail length about 1".
>>
>> I probably could have fixed the problem just with correcting the angle to
>> 70
>> degrees, but while at it I worked over the tails quickly removing the
>> hump,
>> glazing and sharp edge.
>>
>> For S&S though I find more often than not that a combination of incorrect
>> backcheck angle ( I like 70 deg), incorrect backcheck height, tails too
>> short ( I like 1"-1 1/16") , and poor tail arcing ( I like a smooth
>> 2.75" -
>> 3") are the main culprits for poor checking. Strong springs are sometimes
>> part of the problem too, but often just draw your attention to the
>> problem.
>>
>> Attached is a S&S document about installing backchecks.
>>
>> Have a great break!
>>
>> Alan
>>
>>