There is some speculation that he may have repaired classical flutes on a part-time basis too, which might have led him to experiment. Another theory is that it was simply an inventive way of dealing with the problems of age: arthritic fingers had an easier time achieving closure with keys.
Some believe he may have repaired classical flutes on a casual basis, potentially leading to further exploration. Alternatively, another hypothesis is that this method was simply a practical solution for aging hands, making it easier to operate the keys.