A clip comprising: an upper shell (12, 112) and a lower shell (10, 110), coupled together around a hinge pin (50, 133), the upper and lower shells having a pair of jaws on a first side of the hinge pin (50, 133), and handles for squeezing together to separate the jaws on a second side of the hinge pin (50, 133); a biasing spring to oppose the squeezing together of the handles and to urge the jaws together; at least one stop to prevent the jaws from closing completely and to keep the jaws in parallel alignment when no force is applied to handles to overcome the biasing force of the spring; and an adjustment mechanism to adjust the separation of the jaws characterized in that the adjustment mechanism comprises an adjustment screw (38, 138), a washer clip (46, 149), and an insert (22, 122); said adjustment screw (38, 138) comprising a screw head and a threaded shank (40, 140), the shank being pushed through a clearance hole in the lower shell (10, 110), the adjustment screw (38, 138) being held in place around the lower shell (10, 110) by the washer clip (46, 149), and the insert (22, 122) for fitting into a recess in the upper shell (12, 112), said hinge pin (50, 133) being attached to said insert (22, 122); said insert (22, 122) comprising a central block (24, 124) with a tapped hole (26, 126) therein, radial arms (28, 128) extending from the central block (24, 124), and stabilizing wings (36, 136) integrally cast with the central block (24, 124) and radial arms (28, 128), the stabilizing wings (36, 136) at an angle to the radial arms (28, 128); said stabilizing wings (36, 136) for engaging the upper shell (12, 112) in accurate alignment with the lower shell (10, 110); wherein the tapped hole (26, 126) is for receiving the adjustment screw (38, 138) such that the tapped hole and adjustment screw enable adjustment of the separation between the jaws of the upper shell (12, 112) and the lower shell (10, 110) when biasing effect of the biasing spring (54,9 is not opposed by a squeezing pressure on handles. an upper shell (12, 112) and a lower shell (10, 110), coupled together around a hinge pin (50, 133), the upper and lower shells having a pair of jaws on a first side of the hinge pin (50, 133), and handles for squeezing together to separate the jaws on a second side of the hinge pin (50, 133); a biasing spring to oppose the squeezing together of the handles and to urge the jaws together; at least one stop to prevent the jaws from closing completely and to keep the jaws in parallel alignment when no force is applied to handles to overcome the biasing force of the spring; and an adjustment mechanism to adjust the separation of the jaws characterized in that the adjustment mechanism comprises an adjustment screw (38, 138), a washer clip (46, 149), and an insert (22, 122); said adjustment screw (38, 138) comprising a screw head and a threaded shank (40, 140), the shank being pushed through a clearance hole in the lower shell (10, 110), the adjustment screw (38, 138) being held in place around the lower shell (10, 110) by the washer clip (46, 149), and the insert (22, 122) for fitting into a recess in the upper shell (12, 112), said hinge pin (50, 133) being attached to said insert (22, 122); said insert (22, 122) comprising a central block (24, 124) with a tapped hole (26, 126) therein, radial arms (28, 128) extending from the central block (24, 124), and stabilizing wings (36, 136) integrally cast with the central block (24, 124) and radial arms (28, 128), the stabilizing wings (36, 136) at an angle to the radial arms (28, 128); said stabilizing wings (36, 136) for engaging the upper shell (12, 112) in accurate alignment with the lower shell (10, 110); wherein the tapped hole (26, 126) is for receiving the adjustment screw (38, 138) such that the tapped hole and adjustment screw enable adjustment of the separation between the jaws of the upper shell (12, 112) and the lower shell (10, 110) when biasing effect of the biasing spring (54,9 is not opposed by a squeezing pressure on handles.