A grinding jig for holding a blade tool having an edge in a grinding machine, said grinding machine having a grindstone and a support bar for supporting a grinding jig, said grinding jig comprising: - a first and a second clamp half (110, 120) arranged to hold between them at least a portion of a blade tool, and; - an elongate support portion for supporting the grinding jig onto a support bar of a grinding machine, wherein; - the elongate support portion comprises a front end abutment surface and a rear end abutment surface for abutment against a support bar of a grinding machine, wherein; - the front and rear end abutment surfaces (170, 180) are spaced apart such that a portion of a support bar of a grinding machine may be received between the front and rear end abutment surfaces (170, 180) and such that the grinding jig may be moved back and forth relative the support bar, in direction parallel with the longitudinal center axis of the grinding jig, characterized in that the grinding jig comprises: - a first and a second separate grinding jig half (101, 102) which are mutually facing each other and respectively comprises a clamp half (110, 120) and an elongate support portion half (161, 162), wherein; - the grinding jig is arranged such that the first and the second grinding jig half (101, 102) may be releasably forced towards each other to hold a tool blade between the first and a second clamp half (110, 120) and wherein the first and second grinding jig half (101, 102) comprise a respective front abutment half (163, 164) and a respective rear abutment half (165, 166), wherein the front abutment halves (163, 164) and the rear abutment halves (165, 166) are arranged spaced apart from each other on the respective support portion half (161, 162) and configured for abutment with a support bar of a grinding machine. - a first and a second clamp half (110, 120) arranged to hold between them at least a portion of a blade tool, and; - an elongate support portion for supporting the grinding jig onto a support bar of a grinding machine, wherein; - the elongate support portion comprises a front end abutment surface and a rear end abutment surface for abutment against a support bar of a grinding machine, wherein; - the front and rear end abutment surfaces (170, 180) are spaced apart such that a portion of a support bar of a grinding machine may be received between the front and rear end abutment surfaces (170, 180) and such that the grinding jig may be moved back and forth relative the support bar, in direction parallel with the longitudinal center axis of the grinding jig, - a first and a second separate grinding jig half (101, 102) which are mutually facing each other and respectively comprises a clamp half (110, 120) and an elongate support portion half (161, 162), wherein; - the grinding jig is arranged such that the first and the second grinding jig half (101, 102) may be releasably forced towards each other to hold a tool blade between the first and a second clamp half (110, 120) and wherein the first and second grinding jig half (101, 102) comprise a respective front abutment half (163, 164) and a respective rear abutment half (165, 166), wherein the front abutment halves (163, 164) and the rear abutment halves (165, 166) are arranged spaced apart from each other on the respective support portion half (161, 162) and configured for abutment with a support bar of a grinding machine.