When I played Satomi's Suttner concertina, I noticed that the F tone in the middle row on the right hand was slow to speak. So, I tried to reset the F reed.
I dismantled the concertina and removed the F reed from the reed pan.
The gap under the reed tongue was too wide for F as I had expected.
I reset the reed like this.
As you see, there is only little gap under the reed tongue.
Now, the F reed is responsive. It took about twenty minuetes for me to reset the reed.