[CAUT] Digest, Vol 1103, Issue 85 Moving Wippen Rail

[Jon Page]

I was in error a few posts back thinking that the repetition lever
acted as a second class lever within the compound leverage
of the wippen. The knuckle would have to be situated between
the flange center and the capstan for that to happen.
Like it or not a wippen is a third class lever, period.

Moving the rail changes both the load and lift measurements in like manner
thus making any ratio change negligible. To change the Wippen Ratio, one
has to either move the stack (which alters WR by altering the input arm only);
move the capstan (which alters both Key Ratio and WR);
or move the knuckle (which alters Shank Ratio and Wippen Ratio).

A change in ratio comes about by altering either lift OR load not 
both simultaneously
unless you move the capstan forwards and the knuckle further out on 
the shank thus
increasing the input arm and decreasing the output arm. Moving the rail back
increases both input and output.

Any gain in touchweight while moving the wippen rail is a product of 
aligning to
a line of convergence not ratio change.  If ratio were the case then 
the further back
you move the rail beyond convergence, the better the touchweight still becomes.
-- 

Regards,

Jon Page