The sizes are 5 to 7.5 mm for the left hand part and 4 to 6.5 for the right hand part. Specially the lowest hole of the right hand part is smaller than the others. The bore in the head is between 16 and 20 mm decreasing towards the foot to between 12 and 14 mm. The bore of the foot often widens again. The bore is irregular for tuning and tone quality purposes.
Local irregularities are a very important means to influence both the tone quality and the tuning.
In the eighteenth century there did not exist a standard diapason. Even organs in neighboring villages would have a different diapason and tuning. This constituted less of a problem for the string instruments than for the woodwind. The development of the flute from straight renaissance instrument to conical one keyed Baroque flute continues therefore with the development of different means to adapt the diapason. We find warnings in different tutors against just pulling the left hand part out of the head for lowering the tuning as a sufficient means to adapt the diapason.