The storeman advised him that the job required 8Ds. Since there were not enough 8Ds, the shift manager decided that 7Ds would do since they had been previously in place. However, he relied on sight and feel to match the bolts, and erroneously selected 8Cs instead, which were longer but thinner. He failed to notice that the countersink was lower than it should be, once the bolts were in position. He completed the job himself and signed it off. The procedure did not require a pressure check or duplicated check at this time.