This standard establishes the general dimensions of round dies for automatic machines. Compared to round dies made by machine and by hand (see UNI 7579), they have different overall dimensions, with the same nominal thread diameter. The values of these dimensions, external diameter and thickness, in consideration of the particular needs of automatic machines and their die holders, are appropriately calculated based on the diameter and pitch of the thread. This standard applies to dies with ISO metric triangular profile threads:
——coarse pitch (see 3);
——fine pitch (see 4). The number of drain holes and the parts not listed are not bound by this standard.
UNI 7881-1978 history
1978UNI 7881-1978 Ring screw plates for automatic machines with ISO metric threads of triangular cross-section