Method for producing a leaf spring, in particular a spring steel sheet for covering a cooling chamber of a piston of internal combustion engines, which is at least formed as a washer-shaped segment - in which a band-shaped material is fed into a bending device which comprises at least one drum which rotates around an axis of rotation, - in which the band-shaped material is fed in in a tangential orientation to the shell surface of the drum, so that a side wall that determines the thickness of the band-shaped material is in contact at least in sections with a contact surface on the shell surface of the drum, - in which the contact surface of the drum comprises a radius which substantially corresponds to an inner radius of the band-shaped material to be bent to the segment, and - in which at least one diverting mechanism is orientated at a distance to the drum, so that the band-shaped material is forcibly guided between the drum and the diverting mechanism, and by means of which the band-shaped material of the drum is subsequently bent, characterised in that the band-shaped material - is feeded to a circumferential groove in the drum which comprises the contact surface and the contact surface is orientated in the drum at an angle to the longitudinal axis of the drum, so that when the band-shaped material is bent and simultaneously raised, the inner side wall of the band-shaped material comes into flat contact with the base, or - the band-shaped material is feeded to the drum formed in two parts with a lower part and an upper part, wherein a ledge is introduced on a lower part as part of the circumferential groove, and a second part of the groove is provided by a contact surface of the upper part and the upper part is positioned at an angle relative to the lower part, wherein a rotation axis of the upper part is provided in an angle different to rotation axis of the lower part. - in which a band-shaped material is fed into a bending device which comprises at least one drum which rotates around an axis of rotation, - in which the band-shaped material is fed in in a tangential orientation to the shell surface of the drum, so that a side wall that determines the thickness of the band-shaped material is in contact at least in sections with a contact surface on the shell surface of the drum, - in which the contact surface of the drum comprises a radius which substantially corresponds to an inner radius of the band-shaped material to be bent to the segment, and - in which at least one diverting mechanism is orientated at a distance to the drum, so that the band-shaped material is forcibly guided between the drum and the diverting mechanism, and by means of which the band-shaped material of the drum is subsequently bent, characterised in that the band-shaped material - is feeded to a circumferential groove in the drum which comprises the contact surface and the contact surface is orientated in the drum at an angle to the longitudinal axis of the drum, so that when the band-shaped material is bent and simultaneously raised, the inner side wall of the band-shaped material comes into flat contact with the base, or - the band-shaped material is feeded to the drum formed in two parts with a lower part and an upper part, wherein a ledge is introduced on a lower part as part of the circumferential groove, and a second part of the groove is provided by a contact surface of the upper part and the upper part is positioned at an angle relative to the lower part, wherein a rotation axis of the upper part is provided in an angle different to rotation axis of the lower part.