Action flange crushing

[Isaac Sadigursky]

hi,phil! don't spend $160 for screwdriver torque.. i'll be in s.f. in 3
weeks visiting my son and i can bring it for you to try.. with your
experience you have to try it once.. it's like cooking rules of my
grandma's!! a little bit of this and a little bit of that and it works..
it's very simple.. on the dial somewhere between 15-20 lbs you get the
right feel..
anything in the action feeling good becomes loose once it travels with me
in my van under hot californian sun,then all flange screws need to be
re-tightened again,but not too much,otherwise they are crushed..


> [Original Message]
> From: Phillip Ford <fordpiano@earthlink.net>
> To: Pianotech <pianotech@ptg.org>
> Date: 11/17/04 8:15:57 AM
> Subject: RE: Action flange crushing
>
> >inthe early days i remember ptg convention classes and instructor told
> >about 18 lbs torque for hammer and whippen screw.. i got a torque wrench
> >and practiced a little and anybody can get that feell.. it works.. a few
my
> >collegues came to my shop and practiced with torque wrench to get that
> >feel.. try it!!
>
> Isaac,
>
>      Thanks for the response.  This is exactly the sort of info that I 
> was looking for, and for the reason that you give.  It seems to me 
> that this would be useful information for techs (especially beginning 
> techs) so that they could calibrate their hand (or wrist), so to 
> speak.  If it really is important for the flange to be as tight as 
> possible, but not crushed, then it's surprising to me that someone 
> (factory or action manufacturer) hasn't published a torque spec. 
> Also, I would assume that there could be some relation between screw 
> torque and long term tightness of the flange, and that some factory 
> would have investigated this.  My assumption would be that tighter 
> would be better for long term flange tightness, but I've done no 
> experimenting to prove this.
>     I contacted several factory service departments about this.  Not 
> one had a torque spec.  This response from Schimmel might be 
> considered representative (I'm paraphrasing slightly as I don't have 
> the response in front of me):
>
> Thank you for your interesting inquiry.  We rely on the trained hands 
> of our factory technicians to make the screws tight enough but not 
> too tight.  This has worked for us for 120 years.
>
> They then referred me to Renner.  Who then referred me to Renner USA. 
> Who then referred me to Rick Baldassin.  Who then told me that he 
> wasn't aware of any such spec.  He did say that years ago he attended 
> a class given by Baldwin in which they had a torque measuring 
> screwdriver and demonstrated what they considered to be appropriate 
> torque.  Anyone out there attend that class?  Do you remember the 
> torque number specified?
>
> Interesting that you have the number of 18 lbs (is that 18 in.-lbs, 
> by the way?).  One factory rep told me, off the record, that he 
> believed that 12 in-lbs would crush a maple flange.  Also, Guy 
> Nichols seemed to recall that the Baldwin factory used 10 lbs (10 
> in.-lbs?) for action screws.
>
> As soon as my desire for information becomes stronger than my 
> resistance to paying $160 for a torque measuring screwdriver I'll 
> measure some torques myself.  If so I'll report back.
>
> Regards,
>
> Phil Ford
>
> -- 
> Phillip Ford
> Piano Service and Restoration
> San Francisco, California
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