Rotary letter opening cutter and application method thereof

The invention discloses a rotary letter opening cutter and an application method thereof. The rotary letter opening cutter comprises a first shell (1), a key (2), a sleeve (10), a letter opening cutter (4) and a second shell (26); the key (2) is accommodated in a first through hole (3); first positioning grooves (12) are in concave-convex fit with a first positioning projection (8); the sleeve (10) sleeves the key (2); a second positioning groove (13) and a second positioning projection (16) are in concave-convex fit; the sleeve (10) is accommodated in a second through hole (19); a third positioning groove (20) and a third positioning projection (17) are in concave-convex fit; a first clamping piece (7) is clamped with a first annular groove (14); a second clamping piece (31) is clamped with a second annular groove (15); and the first through hole (3), the key (2), the sleeve (10), the second through hole (19) and a support base (28) are coaxial. 本发明公开了种转动的拆信刀具及其使用方法，转动的拆信刀具包括第壳体(1)、按键(2)、套筒(10)、拆信刀(4)和第二壳体(2