damper lever ht.

[Fred Sturm]

	I concur with what Jon is saying. I doubt there is any case where an 
underlever should be horizontal at rest. Certainly this is not a rule of 
thumb to go by. Or if there _is_ a rule of thumb, it is that the underlever 
should slope downwards toward the key.
	 The bottom of a key at the balance rail is about 1" above keybed. The top 
of a keyend felt is about 1 3/8. The bottom of an underlever at rest is 
about 1 1/2". The midpoint of the movement of underlever/key end is about 1 
5/8". The underlever center should be one the line between the key at 
balance rail (1") and that midpoint (1 5/8"), and thus should be higher 
than 1 5/8". How much higher depends on the length of the underlever. What 
angle the bottom of the underlever should be depends to an extent on the 
geometry of where the center is in relation to the underlever bottom.  And 
finer measurements (than + or - 1/8") are desireable.
	I'd spend the time fine sanding and lubricating, as Jon suggests. I think 
you'll find it a more productive use of your time.
Regards,
Fred Sturm
University of New Mexico

--On Thursday, September 11, 2003 4:31 PM -0400 Jon Page 
<jonpage@comcast.net> wrote:

> As I recall from reading somewhere (perhaps the Journal) the underlever
> should be straight out horizontally when the key is fully depressed. So
> the height of the pivot pins should be adjusted to achieve this. I think
> it would be counter productive to have the key lift the underlever beyond
> horizontal.
>
> Also, the key end lifter felt height at rest should be around 1 3/8".
> This will result in the underlever rest position to be about 1 1/2" above
> the key bed. So approximating with 1/4" damper travel at the front end,
> figure pivot height from a horizontal underlever at 1 3/4". I haven't
> tried this but it is where I would start and fine tune from there.
>
> Sand the bottoms of the underlevers smooth on the ends and area over the
> tray lifter felt (if accessible), and coat with McLube 444. Brush teflon
> powder onto the key end felts as well. I've seen/felt some very rough
> surfaces causing excess wear.
>
> Regards,
>
> Jon Page,   piano technician
> Harwich Port, Cape Cod, Mass.
> mailto:jonpage@comcast.net
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> _______________________________________________
> caut list info: https://www.moypiano.com/resources/#archives