Copal Shutter Cut-out Dimensions This table lists the standard Copal shutter mounting sizes in millimeters.   Copal 0 Copal 1 Copal 3 board mounting thread 32.5x0.5 39x0.75 61.0x0.75 flange ring diameter 34.6 41.6 64.0 board hole diameter 34.8 41.8 64.2 front lens cell thread 29.5x0.5 40.0x0.75 56.0x0.75 rear lens cell thread 29.5x0.5 36.0x0.75 56.0x0.75 front to rear cells flange distance 20.0 +/-0.025 20.0 +/-0.025 28.6+/-0.025 All Photographs Copyright © by Gary Gaugler - All Rights Reserved - Use By Permission Only