[Harp-L] harp-l at xxxxx

[Michelle LeFree]

Vern wrote:
> Your SilverWing  system has many desirable features.  However, I question a pointed punch for removing rivets.  A sharp point tends to spread the rivet.  This can make the removal more difficult and alter the hole.  Its only advantage is that it is an easy shape to grind.

Hi, Vern! Long time no see. (Also a long time to get my Harp-L digest  
so I could reply to your message.) I hope all is well for you and yours.

I wrote "pointed" as a general descriptor. The punch actually has a 
flattened tip with the flat just smaller than the diameter of the shaft 
of a typical harmonica rivet. I thought the same thing about the value 
of the nipple-tipped style punches in the beginning and actually started 
with such punches. The hand punch I've used for the last 15 years has 
that feature and it works great. But it was difficult for me to heat 
harden them.  I wanted to keep costs low so I tried a simple tapered 
punch and discovered the added time and expense of machining the tip was 
not necessary in actual practice. I turns out that if you use very light 
force in removing the the affected reed, the punch never needs to 
contact the metal of the reed plate. And, even if it does, the effect of 
the taper is to put a slight chamfer on the hole, which actually makes 
it easier to install the donor reed. It's interesting how something I 
thought was an absolute necessity  on theoretical ground isn't required 
in common practice.

And, from the FWIW column, IMO tapered tips ~are~ more difficult to 
machine than nipple tips. They require a special lathe fixture (compound 
cross slide table) where machining a nipple does not. Any high school 
metal shop student can make nipple-tipped punch with any garden-variety 
lathe. It takes additional knowledge and skill to use the more complex 
machinery required to make the taper.

> I posit that the optimum shape for the punch point is a cylinder about .035? in diameter (a bit smaller than the hole) and about .050? long ( a bit longer than the plate thickness).  This can project from a larger diameter punch shank.  This shape is stronger than a point, spreads the pressure over almost all of the rivet face, and won?t damage the hole if it is pushed too far.

I disagree that the nipple design is stronger than a tapered one.  After 
all, (if you want to be able to see what you are doing in guiding the 
punch) you start with a tapered end and remove material from there. How 
could that be stronger? It can't. And without an expensive gas or 
electric forge that can heat the whole punch uniformly (I use a homemade 
mini-forge that uses a propane torch for the heat source), that nipple 
is very difficult to harden (for me anyway). The tip gets so much hotter 
than the shaft so quickly that you either over-harden or even "burn" the 
tip and under-harden the shaft or under-harden the shaft for proper 
hardening of the tip (if you get my meaning). I broke of a lot of tips 
trying, and forced to use a simple taper decided in the end that the 
nipple tip isn't really necessary.

Since I no longer use the nipple style punch it's a bit moot. But for 
those who want to try it, I preferred the length of the shaft to be just 
short of the plate thickness. I did this to keep the rivet attached to 
the reed. That way I have the option to re-use the rivet. It is a simple 
matter to transplant the reed with the rivet attached. Not so simple 
using detached rivets, even new ones. A loose rivet with  tiny hole in 
it is pretty intimidating to me at least. I never liked using rivet sticks.

> I viewed the video and did not understand how filing the rivet head at an angle can move the reed position.  A large part of the video is dedicated to adjustments after the rivet is set.  This is what often defeated me when I tried to employ rivets.  I?m aware that many technicians use rivets routinely and that my problems may have arisen my lack of skill and experience.  I had much better results with screws.

That is Andrew Zajac's technique, and he is rightly proud of it, because 
it actually works. In practice, I find it is generally unnecessary as in 
my hands the off-center problem occurs infrequently. Gary's results are 
more typical. Although I think I understand it well enough to use it, 
I'll let Andrew explain his method.

Recognizing the role of screws for reed replacement, I have another 
system that uses a drill bit and a tap in small arbors to enable their 
use. It uses the same punches in a similar jig to remove the rivet and 
prepare the rivet pad. Then you drill out the hole and tap it to accept 
a cell phone repair screw. I'll be announcing my all-encompassing 
"Reed-O-Matic" system to in the coming days.

I keep using the phrase "in actual practice" for a valid reason. In this 
case, using screws is significantly more complicated and time consuming. 
In my experience, replacing with screws is usually not necessary except 
for plates that have welded reeds. The vast majority of the time the 
(properly prepped) "used" rivet still attached to the donor reed works 
just great. In instances when that doesn't work I have to start over 
using a new rivet. That nearly always works but it is more "fiddly" and 
hence more time consuming. Honestly, the only time I need to use screws 
is when I am replacing welded reeds from Japaneses or Chinese 
manufacturers who use them.

I have a little rant about welded reeds. Welding reeds during 
manufacture avoids the mechanical pitfalls of using rivets, therefore 
permitting near perfect placement of the reed in its slot (ergo the 
quality of the instruments out of Asian manufacturers and the attendant 
success they are currently enjoying). But welded reeds are no friend to 
the harmonica technician. They require more sophisticated equipment and 
skill. The real problem, though, is the unavailability of replacement 
reeds from the manufacturers who use that method. I don't see any causal 
relationship that would preclude manufactures like Suzuki and Easttop 
(who use welding to affix their reeds) from providing replacement reeds. 
But the fact is you need to obtain an entire harmonica or at minimum a 
whole reed plate from which to harvest a single donor reed. Clearly, 
such manufacturers have a different mindset that doesn't include 
provisions for harmonica repair folk. Obviously they want us to simply 
buy a new instrument if a reed goes south. That just isn't in my budget. 
I ask, do guitar player buy a new guitar when a strings needs to be 
replaced? Not hardly.

The screw method does have one distinct disadvantage compared to rivets. 
You must ream the hole in the reed pad to be able to pass the screw 
through it. Then, unless you are much better at accurately and perfectly 
concentrically reaming the hole in a fragile reed without ruining it 
than I, the problem is centering the reed in the slot. Sometimes that 
can be a real pain and require a lot of time to get it right. And, once 
in proper position, there is always some likelihood that it will work 
its way loose from the screw's grasp again. I believe it is much better 
to have the affixing done mechanically with the rivet matching hole in 
the reed plate rather than relying on the friction of the screw against 
brass to center the reed positively and have reason to believe it will 
stay that way.

> The ideal system would not depend on the location or shape of holes in the reed or plate or on the process of installing screws or rivets,  You would locate the reed in the slot and fasten it without any strong forces or torques on the reed base.   Welding meets these criteria but welders are very expensive .

No doubt. But I designed this to be a tool for the Everyman. I wanted it 
to be both affordable and robust, yet simple enough that technicians and 
even players without much experience (or any at all) could achieve a 
high degree of success in battling the ever rising cost of harmonicas. 
For an outlay little more than a "professional" harmonica costs these 
days, one can repair an unlimited number of broken reeds. It takes me 
about two minutes start to finish to remove the old one andinstall a 
replacement reed and I'm ready to adjust and tune it. That takes maybe 
another, say 5 minutes (I'm not the best tuner around). The biggest 
problem, quite frankly, is obtaining a replacement reed. Some companies, 
to remain unnamed, make it difficult to buy new ones. Companies wo use 
welded reeds often proved to replacements. This why I have asked (and 
received) "dead" harmonicas from all my friends. I now have 2-3 lifetime 
supplies of such donor harmonicas (which often suffered only from an 
easily unclogged reed). I usually offer to return a fully restored 
instrument as incentive in exchange for a few broken ones to do this. 
Happy, happy, all around. I strongly suggest anyone who ever even hopes 
at to some point repair broken harmonicas do the same thing.

> In lieu of welding, I experimented with resistance soldering.  I use it myself.   Although I don?t plan to sell the equipment, I would furnish information to anyone wanting to try soldering. I have illustrated the process in this video:
> https://youtu.be/DOBJCpZQ68Y  <https://youtu.be/DOBJCpZQ68Y>
>
> You can also see my home-grown punch in action.

You are nothing if not an engineer's engineer, Vern. I bow to your 
creativity and ability to make difficult things look easy through 
technical wizardry. Unfortunately, you are one of a kind. We all don't 
possess sufficient technical knowledge and skills to even reproduce your 
innovations. That is one reason I am trying to provide affordable tools 
for "the rest of us."

I appreciate the time you took to review my post and congratulate you 
for designing your novel soldering system. I always ~study~ everything 
you write. Honestly you are one of a handful of my harmonica heroes. We 
need folks like you and Brendan Power to push the boundaries of 
harmonica technology. IMHO, we also need folks who can provide 
real-world solutions for the "journeyman" harmonica player who merely 
wants to maintain his investment in his personal instruments or to help 
a buddy who isn't able to do it for himself. There are a lot of these 
players and only one Vern Smith or Brendan power.

I send all my well-wishes, admiration and respect until we meet again,

Michelle