Ratio question

[Jon Page]

If you don't measure the dip at the front of the key (where it is 1:1)
you have to consider the length of the key and the angle formed from
pivoting on the balance rail and how far back from the front you measure.

For instance, my dip block measures 48 mm in length,
9.9 mm (.390") at the front tapering to 8.4 mm.

That's roughly .19 mm decrease for each 6 mm moved back.

But it is much too complicated for the task involved. Not only do you
have to consider the angle of the key at dip, you have to consider
the rate of height change on the risen key since it is pivoted at the 
back rail.
So the height measured 6 mm back on that key will be ever so
minutely less than the +1mm due to the longer radius (probably half
the rate of change as the 'dipped' key due to twice the radius).

Keep life simple, measure dip at the front, 1:1.

The amount of dip is dependant on what is required for regulation
but that's a different topic.
-- 

Regards,

Jon Page