"So if the Asian manufacturer considers 4 mm easier and close enough the pin will be oversize. WW II drawings give the pin diameter as max/min 0.158/0.154 ." Isn't 4.0000 mm = 0.1575 inch? If so, 4 mm is within the quoted WWII spec size range. The problem would not be specifying 4 mm but the tolerance that was placed on that measurement. 73, Andy, k3wyc