[CAUT] Jack speed - Teflonized cloth

[Fred Sturm]

On Nov 14, 2006, at 9:37 AM, davidskolnik at optonline.net wrote:

> Fred - I may be wrong, and in any case, am assuming you have the  
> part in hand (unmounted), but I have always measured at the end of  
> the lever leather.  I'm not sure I know where the "standard 1" "  
> comes from in this case.  Clearly this is an important question to  
> clarify, as, lacking such consensus, we may as well be describing  
> the resistance in colors.

Hi David,
	The 1" standard is often used for hammerflanges, as their lengths  
differ, in some cases by a great deal. So if we want to have a  
standard friction for all hammerflange centers, some standard  
distance is needed. For rep levers, the distance from the center to  
the leather is pretty close to standard on all butterfly spring  
wipps, so one could have that be the standard. It does make  
considerable difference where you measure, hence my question.
> I may be wrong, but I simply disengage the lower arm from the jack  
> hole and, VOILA! You can measure both lever and jack.  The express  
> version would, I suppose, be to hold the wippen in one hand from  
> underneath, with my thumb and another finger, pull down the upper  
> spring arm.  That works too
Well, with spring released from the jack, the jack is now free, but  
the spring still wants to touch the rep. To hold the rep side of the  
spring down, with jack side engaged, you need to compress it quite a  
bit to get enough motion to measure, meaning you might be weakening  
it noticeably. Trying it again as I write, I find that, yes, I can  
rotate the spring enough when it is released from the jack to have it  
enough out of the way. Putting that end back in the jack isn't my  
favorite thing to do, but that seems to be the way to go. Thanks. I  
guess I hadn't fussed enough.
> I do not like use fluted reamers on this material. I don't think  
> they are sharp enough to cut cleanly.  I make up roughened center  
> pins which I carefully measure (to .0001" resolution) to have  
> better control of the sizing.
I don't use fluted reamers either. I use roughened music wire, AKA  
Mannino broaches. And I use un-roughened music wire to burnish, with  
a fast enough action to create heat from friction, to pack the  
fibers. But with the teflon added, this seems to change the behavior  
considerably, and these techniques don't seem to work.
	BTW, Steinway's recommendation about using methanol should be  
clarified to include the notion of a TINY drop applied directly to  
the offending bushing. Large quantities will wash the teflon out,  
leaving you with a mushy cloth bushing - not a good thing - so Eric  
and Kent tell me.
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu

-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/caut.php/attachments/20061114/790824ed/attachment.html