A chainsaw (100) has a chainsaw body (101), a cutting chain (103) driven by a motor, and a guide bar mounting stud (111) extending from the chainsaw body (101). The chainsaw (100) also has an adjustably connected guide bar (102) having a track for supporting the cutting chain (103) around a periphery of the guide bar (102) and an adjustment pin (114) extending from a side face thereof. The guide bar mounting stud (111) is configured to extend through an elongated slot (112) in the guide bar (102). The chainsaw (100) also has a cam (116) received on the guide bar mounting stud (111) and having an eccentric groove facing the guide bar (102). The adjustment pin (114) is received in the eccentric groove such that rotation of the cam (116) causes the guide bar (102) to move with respect to the chainsaw body (101), thereby tensioning the cutting chain (103). The chainsaw (100) also has a clutch (118) connected to the cam (116) for allowing no more than a predetermined load to be applied to the guide bar (102) for tensioning the cutting chain (103).