[pianotech] Brumbach Rebuild

[Paul McCloud]

Hi, Jon:
	Thanks very much for the information.  There is a lot to tend to on this. 
It would make an excellent Chapter project.  Like, how many things can you
spot in the picture that are wrong.  Since the original parts aren't
around, trying to figure out what would work best is a puzzle.  I don't
have the piano in the shop, so I'll have to see about the string height,
etc.  
	You make it sound so easy...
	Paul McCloud
	San Diego


> [Original Message]
> From: Jon Page <jonpage at comcast.net>
> To: <pianotech at ptg.org>
> Date: 11/01/2010 4:39:52 PM
> Subject: Re: [pianotech] Brumbach Rebuild
>
> Start with rectifying known coefficients.
> String height minus hammer bore = hammer center height (HCH);
> more or less depending on hammer pitch and string angles
> to achieve a 90 degree contact.
>
> Wippen center height works well if it is 2.5" below HCH.
>
> Coordinate this with action spread such that the knuckle core aligns
> with the jack center at rest (90 degrees to the shank if possible).
> Read Bob Hopf's article on Action Elevations.
>
>  From the placement of the drop screw, I'd say that the spread is too
short
> which accounts for the capstan on the rear of the cushion and the contact
> position of the tender appears to be on the front side of the let off
button.
>
> Once you get these in sync you can decide if the capstan has to move to
> get it all to regulate properly such that the jack sufficiently 
> clears the knuckle
> or does not become bound against the rep stop felt when the key is fully
> depressed. Then you can decide on the heel height to intersect the ML.
>
> It's a cinch.
> -- 
>
> Regards,
>
> Jon Page