Method and apparatus for forming a profile groove in a key blank

A method of forming a profile groove in an elongated key blank having a key blade with opposite side surfaces, said method comprising:

• forming said profile groove in a surface of said key blank by means of a broaching tool with at least one tooth which is forced and guided longitudinally in parallel to said elongated key blank so as to cut out material from said key blank into a desired profile shape, corresponding to a cross-sectional shape of said at least one tooth, said profile groove extending in a predetermined area from a distal end of the key blade towards a grip portion of the key blade, while
• at the same time holding said opposite side surfaces of the key blank between opposite holding surfaces of a fixture, causing a firm abutment and retaining action on the longitudinal side surface portions of the key blade located adjacent to and all along said profile groove being formed, whereby the key blank material adjacent to said profile groove is retained in a fixed state without being deformed during the broaching operation,
• wherein said profile groove has at least one undercut portion defined by an inner bottom wall and an opposite wall on an inside of a ridge portion, an outside of which forms at least a part of said longitudinal side surface portions being held by said fixture during said broaching operation, and wherein said at least one undercut portion is extended into a configuration formed as a pocket having opposite side wall portions and a transverse end wall portion.