S & S capo/Case hardening

[Ron Nossaman]

I haven't done any experiments on case hardening capos, so I really can't
speak directly to the pros or cons. I can throw in some peripheral
observations however, on what I have seen, heard, and done.

Half hard brass has a compression strength limit of about 50k PSI. The cast
iron average is around 100k PSI, with hardened iron going up to 200k, or
twice to four times that of brass. At the tenor/treble scale section break,
the string termination system changes from a softer brass agraffe to a much
harder cast iron capo. That's also where the whistles, zings, buzzes and
shrieks start - in the capo section. If harder is better, how does this
equate? If harder is better, there should be fewer noises in the capo
section than in the agraffes, not more. Shouldn't there? What's different?
Maybe the higher frequencies really do need harder terminations. It's just
an unfortunate coincidence that the noises start immediately above the
agraffe section. That's it, it's just one of those mysterious cosmic things
that we weren't meant to fathom, right? God's little joke on the designers
and techs. 

It's the front duplex, gang. When you touch the duplex and the noise stops,
why would the conclusion be that the capo needs to be hardened? This doesn't
compute. Increasing the draft angle and shortening the duplex lengths takes
care of the problem quite dramatically, and it's simple and easy to do in
the privacy of your own shop. I've done it. It works. It didn't take any
superhuman attention to the capo shape, or require any high tech induction,
flame, or transmogrificational case hardening. It's simple, it's (as nearly
as I can tell) reliable, it's measurable and understandable, and you don't
have to wear the pointy hat with the stars to get it to work. Occam was
right, in my opinion.

Ask yourself: why aren't we using high carbon steel agraffes, hardened to
the point of scratching diamonds? Evidence is that it doesn't seem to be
necessary. I wonder at the efforts gone to to attempt to make a suspect
design "feature" work when the simpler method is to eliminate the feature in
favor of something that does work. Why is it necessary, at any cost, to
retain the design feature that is the problem in the first place? If we have
the permission, the funding, and the ability to fix it, why not just fix it?


Just wondering.

 Ron