RE: CX 12 spring mods [was tight slide action]

["MLeFree" <mlefree@xxxxxxxxxxxxxxxxxxxxxx>]

CXfried related his treatment of the CX spring:
> I got this tip not from G's website but developed this measure when Hohner
send
> the first black CX 12 to a customer, a fried of mine. It happened that I
just visited
> him on the day the postman had delivered his CX 12 and he was eager to
show me
> how easily the CX 12 can be taken apart. Orrps, because he was not
cautious enough
> he broke the cover slots when removing the spring band.
>
> I not only rounded the sharp band edges but also filed them back so that
you
> needed to to press down only one band end to get the band free.  8<snip>8

Siegfried, I found this recommendation in the harp-l archives from when you
originally posted it years ago.  The reasoning you suggest for filing the
edges sharp makes sense, but I think that doing so creates a new problem.  I
agree wholeheartedly that the CX spring is the weak point of the design.
I'm sure that machining the culprit sharp corners in the production of the
instrument to a shape that would conform to the inside surface of the comb
at the key points of contact would cost several times what it does to simply
make that sharp-edged corner.  This is a typical management decision made to
cut manufacturer's cost.

However, IMHO, filing the sharp corners round as you (and G) suggest is not
the answer to this manufacturing shortcoming.  The reason I say this is that
once the stock spring is properly installed the sharp corners, though the
wrong shape, ~are~ spaced the appropriate distance apart so that the slide
is prevented from moving along its length.  That's the whole idea behind
making the comb slots half the full thickness of the spring in the first
place.  The "field modification" that you suggest makes the tabs more the
correct shape, but it narrows the distance between the points at either end
of the spring where they would otherwise contact the comb and prevent the
spring from moving longitudinally.  Filing the edges back even further
compounds this problem, in my view.  The result?  The modified CX becomes a
veritable hand grenade.  If ever there is a significant shock or the
instrument is dropped, the spring can be bumped or even move due to its own
interia.  Because there is nothing stopping the spring from moving in either
direction along its length, the spring can easily pop out, causing the
harmonica to explode!  (Please don't ask me how I discovered this.  :)

I think you'd agree that the real problem caused by the sharp corners occurs
primarily if not exclusively during the assembly and disassembly processes.
Everything's fine once the (stock) instrument has been properly assembled.
Therefore, I contend that the best approach to avoiding damage to the comb
from the sharp corners is ~very~ careful and well-practiced spring
installation (and removal) technique.  You have to: 1) maintain a firm grip
on both ends of the comb and apply even pressure to both ends of the spring;
and 2) be very vareful not to release the pressure you apply to the spring
as you slide it along its length and insert it carefully into the slots in
the comb until it is properly seated.  The reverse procedure should be used
to disassemble the harmonica.  If you do this carefully, you will do no
damage.  It's only when the tension you've applied to the spring is released
before it is in the proper position relative to the comb slots on either end
that damage is a problem.

At least that's the way I see it!  8^)

Respecfully,

Michelle