3 Identical Custom Pneumatic Notching Dies mounted to a common Self Centering Device. The Center die is Stationary and the outside dies move together, in opposing directions along a Dual V Roller System. Each die is manually Adjusted to multiple sizes and Notching locations. Punches 3 Notches simultaneously with each stroke. Each Pneumatic Die Can be turned on or off when punching one or two notches only is required. Punches Clearance Notches for a Casement Window Impost Rail.