Hitch Pin Replacement Question

[pianoguru at cox.net]

---- Ron Nossaman <rnossaman at cox.net> wrote: 
>Make a rubbing of the bass hitches ....There's a ton of iron in most bass 
> risers, so you aren't giving up anything important in 
> strength, and there's not much breeze under there, so they 
> won't whistle - and the mice won't tell.

Almost every piano I have designed since the late 80's has an inverted U-channel bass hitch panel, vertical and grand.  The hitch panel, where drilling is done, is the same thickness in all regions of the scale, about 5/8".  Any hitch pin, in any register of the piano can easily be driven out for repair or replacement.  The U-channel configuration is not significantly weaker than a solid mass of iron for the bass hitch panel.  

There are other advantages, though.  In the manufacture of the plate, areas of greater mass cool more slowly than areas of lesser mass.  This variance of cooling rate results in twisting and distortion of the plate.  By "shelling out" the underside of the bass hitch panel, a huge inequity in mass is resolved, and much less dimensional distortion occurs.  

I know this doesn't help you with resolving this problem in traditionally designed pianos already out there.  It's just to let you know that there are piano designers taking such things into consideration.  

BTW, I am NOT a fan of vertical hitch pins.  However, if a rebuilder should choose to replace my 'traditional" hitch pins with vertical hitch pins, it shouldn't be a problem, as long as the hitch pin locations are not rearranged into a "break-here" perforation line (as Ron as previously described it), or the plate positioned so low that the strings must be so high on the hitch pins as to multiple the leverage force at the hitch pins unnecessarily high.

Frank Emerson