A method for releasing a bolt included in by a compound bolt, wherein the bolt has a first end portion, a second end portion and a longitudinal axis and is provided with a transverse bolt head at its second end portion, wherein the compound bolt includes the bolt, a nut and a safety device arranged between the transverse bolt head and the nut, the safety device being provided, on the side facing the bolt head, with at least one locking body projecting axially, wherein the bolt includes a cylindrical portion, at its first end portion, with an external thread for the nut with a complementary internal thread, wherein the transverse bolt head is arranged to be moved through a slot in an object from the front of the object and then be rotated around the longitudinal axis until the bolt head engages with the object at the back of the object, wherein the locking body projects, in an active position, through the slot and out at the back of the object so that the transverse bolt head is prevented from rotating out of its engagement, wherein the thread of the first end portion of the bolt is provided with a deformation portion so that the internal thread of the nut is non-complementary to the thread of the deformation portion, and wherein the bolt is fitted by: - moving the transverse bolt head through a slot in an object; - rotating the bolt around the longitudinal axis until the transverse bolt head is in engagement with the object; - moving the safety device which is provided with at least one locking body until the locking body projects through the slot and out at the back of the object so that the transverse bolt head is prevented from rotating out of its engagement; and - tightening the nut against the safety device, and wherein the bolt is released by loosening the nut from the safety device; and moving the nut along the thread towards the first end portion, characterized in that the method further includes: - moving the nut onto the deformation portion; and - rotating the nut and the bolt at the same time so that the transverse bolt head can be moved out of the slot. wherein the bolt has a first end portion, a second end portion and a longitudinal axis and is provided with a transverse bolt head at its second end portion, wherein the compound bolt includes the bolt, a nut and a safety device arranged between the transverse bolt head and the nut, the safety device being provided, on the side facing the bolt head, with at least one locking body projecting axially, wherein the bolt includes a cylindrical portion, at its first end portion, with an external thread for the nut with a complementary internal thread, wherein the transverse bolt head is arranged to be moved through a slot in an object from the front of the object and then be rotated around the longitudinal axis until the bolt head engages with the object at the back of the object, wherein the locking body projects, in an active position, through the slot and out at the back of the object so that the transverse bolt head is prevented from rotating out of its engagement, wherein the thread of the first end portion of the bolt is provided with a deformation portion so that the internal thread of the nut is non-complementary to the thread of the deformation portion, and wherein the bolt is fitted by: - moving the transverse bolt head through a slot in an object; - rotating the bolt around the longitudinal axis until the transverse bolt head is in engagement with the object; - moving the safety device which is provided with at least one locking body until the locking body projects through the slot and out at the back of the object so that the transverse bolt head is prevented from rotating out of its engagement; and - tightening the nut against the safety device, - moving the transverse bolt head through a slot in an object; - rotating the bolt around the longitudinal axis until the transverse bolt head is in engagement with the object; - moving the safety device which is provided with at least one locking body until the locking body projects through the slot and out at the back of the object so that the transverse bolt head is prevented from rotating out of its engagement; and - tightening the nut against the safety device, and wherein the bolt is released by loosening the nut from the safety device; and moving the nut along the thread towards the first end portion, characterized in that the method further includes: - moving the nut onto the deformation portion; and - rotating the nut and the bolt at the same time so that the transverse bolt head can be moved out of the slot. - moving the nut onto the deformation portion; and - rotating the nut and the bolt at the same time so that the transverse bolt head can be moved out of the slot.