Abstract: An improved burster for separating continuous business forms stationery assemblies into individual form lengths of the type including an infeed mechanism for driving the continuous assembly into a burster which, in turn, separates the assembly into individual form lengths which are placed on a conveyor to be conveyed to a stacking tray. The burster includes a powered mechanism whereby the burster, the conveyor, and a portion of the stacking mechanism may be simultaneously adjusted for various form lengths. Also incorporated is an automatic electrical system responsive to such adjustment for automatically adjusting the conveying rate of the conveyor to insure proper shingling of the individual form lengths thereon. The burster is in a housing having a movable cover whereby access to the various mechanisms may be obtained. A control system provides for jogging of the mechanisms with the cover open that precludes continuous operation for safety purposes.