The imperforate stamps from 1906-08 were issued without perforations specifically to supply private stamp vending and affixing machine companies. These early automated companies purchased uncut sheets of 400 stamps from the Post Office. They then cut the sheets into rolls (coils) and applied their own proprietary perforations or slots so the stamps could dispense from their machines. A guide to these proprietary perforations can be found by clicking the button below.

Vending machines required stamps with straight edges, either on the top and bottom or on both sides to operate the machines. Initially the Bureau perforated sheets in only one direction and then cut them into strips. These strips were then hand pasted into rolls and sold as a roll of coiled stamps.

The process of pasting together the strips was labor intensive and coils were not cheap to produce. The advent of the rotary press saved the day.

The blades in the both the first experimental machines were much to be desired and usually meant separating the stamps meant a torn stamp. The private perforations were employed to aid separation. Various perforations were used.

Because of high demand from philatelists, postal authorities made these imperforate sheets generally available to the collecting public, allowing them to acquire blocks, strips, and position pieces.