bouncing Schimmel hammers

[Richard Brekne]

Hi Richard

This description below rules suggests perhaps something along what Jon 
suggests, and a jack that gets back under the knuckle very quickly.  If 
you have close letoff and little drop and a strong rep spring to boot... 
then the jack can get back well before the hammer hits the string for a 
staccato blow. 

The hammer has to be rebounded by something, and there are only a very 
limited number of things that can do this, and many of these are ruled 
out if checking goes as usual for all other kinds of blows. I assuming 
at this point that all fff blows with the key kept down will check as 
usual.  If this is the case.. then you are looking for something in the 
whippen and keys that only happens with quick release... and this speaks 
to me of how the action resets for repetition.

If the jack is back under (as it really should be on a staccato blow) 
after hammer impact, and the key and whippen combine to create enough 
resistance to the hammers downward force, then you will get a double 
blow.  Tight key pins, tight whippen flanges, and stiff repsprings come 
to mind real quick. A too loose jack pinning could also contribute 
somewhat I suppose.

Perhaps a few UW and DW samples might be enlightening ?  That would give 
us both BW and frictions figures.  If BW is reasonably low and friction 
is high and your hammer flange centers are not the source of the high 
friction, well you see where I am going.

Cheers
RicB


    This is not a backcheck issue, because the bouncing happens on a sharp,
    staccato blow that does not put the hammer in check. 

    Richard