Swingline 4 Hole Punch
Paper punched with four (4) holes can be used in several different ways.
The Project board utilizes a four (4) ring binding mechanism to secure the 15 inch side of 15″ x 21″ drawings.
When a project is completed the full set of drawings can be bound into sets for filing.
in a Hafrak Plan File using screwpost fasteners and the four (4) holes originally punched for use with the Project Board.
And, of course, world wide metric binders utilize a four (4) ring binding mechanism making four (4) holes necessary.