[pianotech] Capo Bars

[Mike Spalding]

David,

Just guessing, but maybe they don't do it because it's harder than it 
looks. The verticals (Kimball, for example) that do it this way have 
tonal issues at the end of the rod, or at the break, because they didn't 
achieve good seating of the rod in the groove and the downbearing force 
isn't sufficient to force the rod to seat.

I have done this on one small grand, where shaping the capo exposed a 
lot of air pockets in the cast iron. 3/32" diameter "music wire" from 
the local True Value. Plenty hard, plenty smooth, and about the same 
radius as I aim for when reshaping the capo. Machined the groove by hand 
with a Dremel grinder, fiddled with the rod until it seated fairly well, 
and bedded it in J B Weld epoxy. Sounded pretty clean, but it would have 
been easier to just grind a decent shape on the capo.

Mike

David Love wrote:
>
> Why do manufacturers harden capo bars rather than cast (or grind) the 
> underside of the strut flat, rout out a groove to receive a steel rod 
> of proper radius, shape and hardness and insert it there where it 
> could, when it’s worn, be easily changed and where the consistency 
> would be more easily controlled. Is there a compelling reason not to 
> do it that way?
>
> Secondly, if I were to do that to a piano where I have some concerns 
> about the hardness and or consistency of the capo, what specific 
> material and diameter would be best to use for the rod insert?
>
> Any thoughts appreciated?
>
> David Love
>
> www.davidlovepianos.com
>