Hello -- after a few questions about organ scales for small crank
organs, I made pictures of some of the more common scales as I use
them for arranging:  Carl Frei 20er, Alderman 26er, Raffin 31er,
German 26er, Hofmann 28er, Gem Roller 20er, Sankyo 20er,
Schmieder 16er, Triola.

Each picture shows the notes that can be played on the scale, ordered
from lowest to highest; the track on the roll is shown as a number and
as an absolute measurement in millimeters from the bass edge.  (For
arrangers, this is more useful than showing the notes as ordered on the
roll or tracker bar).

One item requires an explanation: The "repetition distance" is the
minimal distance from the end(!) of one hole (or pin or slot) to the
beginning(!) of another one for the same note so that the instrument
produces an audible break, i.e., it "repeats" the start of a note.

For all scales based on the 20er, there is some discussion whether the
exact track spacing is 3.85 mm, 3.86 mm, or 3.87 mm.  Herbert Juettemann
gives 3.85 mm, some German organ builders claim 3.86 mm. In practice,
the difference over 20 notes is at most 0.02 x 19 = 0.38 mm; over the
widest scale (Hofmann 28er) it is 0.02 x 27 = 0.54 mm; this is a visible
difference, but real organs with any of these tracker bar spacings will
play rolls of all three track spacings.

The pictures do not show all measurements necessary for punching.
Missing specifications are, e.g.,

* "spiral correction" (of the scales above, only the Triola is punched
with spiral correction)

* maximum distance between two holes or pins if a note is to sound
continuously

* typical raster sizes for punching

* maximum length of slots if slots are punched (only for Triola)

For the 20er Gem Roller, I do not know the track spacings.  Moreover,
all the measurements should have tolerances added to them.

I hope I did not misspell a name; in case I did, let me know, then
I'll correct the corresponding picture.

Regards
Harald M. Mueller

 [ Thanks Harald, I'll place the images at the MMD Sounds site,
 [ http://mmd.foxtail.com/Sounds/ 
 [ -- Robbie