Abstract: A high speed mail sorting machine which includes an improved screw conveyor in the magazine section and an improved pick off device for separating the individual envelopes from one another. The screw conveyor includes four driven rollers having spiral grooves for receiving the lower edges of the envelopes to convey them along the rollers. A pair of raised rollers with spiral grooves maintain the envelopes in a vertical orientation as they are conveyed along the lower rollers. The pick off device includes a conveyor belt and a relatively strong vacuum box which draws the leading envelope against the belt. An opposing vacuum box of lesser intensity draws any stuck envelopes away from the leading envelope to assure separation. The opposing vacuum box has a beveled surface which effects a staggered shingle arrangement of any extra envelopes adhering to the leading envelope.