Over the years I have used various means of obtaining the recommended
accordion collapse spacings of  1/16"- 1/8"- 1/4"- 1/2", such as slide
calipers and wooden blocks of the required thickness.

The other day I was talking to my friend Graham along the lines of
reducing the travel of the accordion for Duo-Art's that tend to play
too loud, but maintaining the accordion 1-2-4-8 ratio.

He suggested Playing Cards!  Why didn't I think of that before?

I took a pack of cards and arrived at 43 cards (thicknesses) to the
1/2" (8-A).  From this point I went to:-

 1-A.   2-A.  4-A.   8-A.
   6    12    24     48  cards
                     43    "
   5    10    20     40    "
   4     8    16     32    "

Of course to obtain the recommended spacings I needed to use thinner
cards.

With varying numbers of cards I found I could maintain the 1-2-4-8
ratio and vary the accordion travel to suit the piano, such as slightly
more travel for soft pianos and less travel for loud pianos.  Or
maintain the recommended collapse spacings.  Do I hear, "Just use
a metric slide caliper and a calculator", as just another option.

Ian McDonald