A rotatable cutting head (102) for a vegetation cutting device (100) comprises: a rotatable spool (206) having a cutting line (116) wound thereon, a free end of the cutting line (116) being arranged to exit the cutting head (102) via an opening (216). A cap (118) comprises a feeding mechanism (350), the feeding mechanism (350) comprising a peg (602) for engaging with the spool (204) and configured to allow the spool (204) to rotate relative to the cutting head (102) and feed cutting line (116) from the spool (204) when the free end is short than a predetermined length. A moveable locking mechanism (220) is configured to move between a locking position in which the locking mechanism engages the cutting line feeding mechanism (350) and limits relative movement between the cutting head (102) and the spool (204) land a release position in which the locking mechanism (220) does not engage the cutting line feeding mechanism (350). The cutting head (102) comprises a spool (204) comprising: a central portion (334) for receiving the cutting line (116) wound thereon； a flange (330, 332) connected at one end of the central portion (334). The flange (330) comprises an internal track (702) on a base of the flange configured to guide the peg (602) of a feeding mechanism (350) in the cap (118), the internal track (702) comprising at least one notch (708) for engaging the peg (612) and preventing relative motion between the cutting head (102) and the spool (204). At least one external camming surface (370) is on a peripheral edge of the flange. The camming surface (370) is configured to engage with the moveable locking mechanism (220) as the spool (204) rotates relative to the cutting head (102) and cause the moveable locking mechanism (220) to move between the release position and the locked position.
