[Harp-L] On Tolerances

[Snaruhn@xxxxxxx]

Hi ron and Ludo,

OK, there´s a little point I have to correct myself when I assumed Ludo
had meant I would mix the reed with the slot.

< ..it is NOT working at the reedtip end ....>

I only recognized "reedtip" and not that the slot end = the end where the 
reedtip 
is was meant. My mistake! 

However, I stick to what I said about embossing just this part of the slot 
and
not its sides. 

I think it´s necessary to clarify the understanding of the term "gap" before
explaining my view point. We certainly agree that "gap" is the distance 
between 
reedtip and slot wall? However, once we are talking about the gap we should
examine the matter in toto.

A fixed reed has 4 kinds of tolerances which are partly necessary partly
can cause anger. The most important is of course the offset = the distance of
the reedtip to the plate surface and is even crucial for starting the 
vibration.

Important is also the tolerance of the reed sides or edges to the 
longitudinal 
slot walls. In the accordion production the extent of this tolerance makes 
the
difference between a quality accordion and an average instrument. The 
reedplates
of the latter are factory made, while the top plates are handmade.

Harp reedplates are basically not handmade but these tolerances are 
acceptable.
Not to forget: harps are mass products. That applies also to the harp 
Stradivaris:
Polle Concert Harmonica, Hohner`s Silver Concerto, BobDoug`s Renaissance.
They all have reedplates ex factory. 

An angry tolerance is occasionally a too big distance of the reed backside to 

the plate surface, exactly spoken, the reeds are curved convex (leackage!). 
The reason is obvious. The reed is rivetted ON the plate by a machine. By 
means of razor blades under reedtip and reedroot curved reeds can be bent 
cautiously below the plate surface.

However, the most angry tolerances are the "gaps". The different extents at 
the single reeds clearly show that we have to play on mass products. But 
these "holes" can be diminished by shifting the reed towards the tip 
(nothing for persons with two left hands), or giving any material to the slot 
end 
or embossing the plate at the slot end.

Note:
It isn´t advisable to emboss the slot sides because the tolerance here is a 
fraction of a mm and one risks that the reed sticks.

Well, Ludo, the term "embossing" doesn´t point to the spot where the 
embossing is performed, it´s just a kind of working a metal surface, no more no less.

Ron, I hope that your offlist post is answered simultaneously.   

Siegfried