opening that has produced it. Similarly, in punching operation, after the strip is stripped off the punch, the material recovers and the hole contracts. Thus, the hole is actually smaller than the size of the punch which produced it. This difference in size due to elastic recovery will depend upon: blank size, stock thickness and stock material. It may be taken as between 0•0125 mm and 0•075 mm. If the stock thickness is upto 0•25 mm, this difference may be taken as zero. For stock thickness between 0•25 mm and 0•75 mm, it may be taken as equal to 0•025 mm and for stock thickness more than 0•75 mm, it may be taken as 0•050 mm. Thus to produce correct hole and blank sizes, the punch size should be increased and the die opening size should be decreased by an amount as explained above.