Capstans

[John Hartman]

Del,

In the March 2000 issue of the Piano Technicians Journal there is an
article I wrote about using the drill press to instal capstans. The
tapered "chuck" grabs the capstan with enough friction and is easily
made on a wood lathe. I have made a change in my procedure and have made
a new "chuck" out of 1/2" canvas reinforced phonelic rod (MSC
#75963412571). The same tapered hole is machined into the bottom. I got
this Idea from Ted Sambel and have used it successfully for reinstalling
capstans in old key as well as for new keyboards.

Give it a try, it works great.

John Hartman

Delwin D Fandrich wrote:

> From the information given, I'd guess an oversized pilot hole. Let me
> make a distinction here, as well. It is possible that a factory might
> successfully turn the capstans in place. This would be done with a
> machine that would precisely grip the head of the capstan holding it
> nice an true and then spin the capstan down with no side play on the
> capstan at all. This is not how we would do the operation in our
> shops. We take a capstan wrench -- of whatever type -- and slowly
> crank the thing down. They wobble all over the place finding their way
> down as best they can. By pressing, rather than turning, the capstan
> into a properly sized pilot hole, it is driven straight into the hole
> without much damage to the sides of the hole. I've tried it both ways
> and have consistently found those capstans I have pressed home to be
> straighter and tighter than those I have turned in. However, your
> mileage may vary.... If it works better for you to turn them home,
> then that it the proper way for you. We'll keep pressing on. Del
> -----------------------------------------------------------------------
>
>      ----- Original Message -----
>      From: Dave Nereson
>      To: pianotech@ptg.org
>      Sent: January 07, 2001 11:37 PM
>      Subject: Re: Capstans
>       I recently tried to regulate a brand-new Boston studio.
>      The capstans wouldn't stay regulated.  I'd regulate them,
>      then after tuning, there'd be too much lost motion again.
>      The capstans were being pushed down into their holes even on
>      a medium-hard blow, and no, I wasn't pounding the heck out
>      of it.  The factory must've a) drilled the holes too large,
>      or b) pressed, rather than turned them into their holes.  Or
>      maybe the holes expanded due to the dry Colorado climate
>      ?      --Dave Nereson, Denver
>