Hi Ron N and Bill Shull, It's not just a matter of hardening the capo, it's also important...vital to reshape the capo bar! The reason for hardening it is that if you bring the capo to a fine enough point to give a good clean termination, the string will bite into the bar creating more problem than it solves. When the combination of good profile and hardening come together the result is a clearer, cleaner tone. The front duplex needs good termination all round to work. Most pianos that have noise coming from that section will have big fat capos and front duplex/V bars. I speak from experience, the work that Ron Overs is talking about was done to two piano plates in pianos that I have rebuilt. Both had unbelievably noisy front duplexes and a string breakage problem. The work in one (a Yamaha C7E) has been in heavy concert use for a bit over two years now and the tonal clarity is still as good as when the job was just finished. No string breaks since either....mind you I'd expect that, given that the piano was restrung. The other was also a great success (though is not worked so hard). Its not just the capo bar that is profiled either, the front duplexes (or V bars) are shaped and profiled as well. I'd recommend a look at the picture on Ron's web site www.overspianos.com.au It may give you a better idea of what he does, it clearly shows the V bars on one of his rebuilds. The other alternative for anyone interested is to come to the Australasian Piano Tuners Convention next year in Sydney (in early July, pre-Olympics). Ron will be lecturing and showing at least one of his pianos there......stay tuned for details! Bill, I disagree that simply restringing and light preparation of the surfaces will solve the problem. I've tried this and found that the problenm recurred sooner than I had hoped, it is only a temporary solution. given the costs involved in quality rebuilding, that can present problems with customers later. Regards to all Mark Bolsius Ron Nossaman wrote: Subject: Re: S & S capo/Case hardening Date: Tue, 2 Mar 1999 2:05 AM 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
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