Schaff longer new upright spring!

[Richard Brekne]

Terry wrote:

> Now I haven't tried this, so I may well be speaking out of ignorance, 
> but I have a reasonable concept of how much flange friction there will 
> be with 3-4 grams of resistance. A jack weighs almost nothing. Seems 
> to me if the jack needs to swing freely 7 full swing cycles, that 
> would require almost no friction in the center. Three to five grams 
> friction in an action center with a shank and hammer hanging from it 
> will swing maybe three full cycles - and that has tons more momentum. 
> Seems like something may not be right here???
>  
> Terry Farrell
>
Ok... I said 3 to 4 grams to begin with.. not 3 to 5.   5 is going to be 
too much.  And 3-4 grams is what Steinway H. uses in hammer flanges and 
pretty well is reflected in their tap test. I know how this feels and 
equate it to the same in jacks, and that is just dandy.  But, as long as 
you put a finger on it... what exactly this works out to in grams of 
friction to the 2nd decimal point I am not sure... :)  The point being 
here... that it needs to be as firm as is can be whilst still being free 
to rotate quickly and easily in the bushing...  We need to get away from 
all these numbers and specs.  Great for reference I'll admit... but once 
you have a feel for something... put the rulers and gauges away.

Cheers
RicB



> > Hi Julia,
> >
> > You can't bake a cake without a pan. Get a gauge--get the best one 
> you can
> > afford. There is a swing test as well. There are two ways to count the
> > swings. 7 full cycles or 13 back and forth. Good luck.
> >
> > Regards,
> > Don Rose
>  
> >  Check the jack center pins to 3-4 grams of friction and for firmness