-----

cycles produced by MCB (Monark Crescent Bicycle) have metric threaded ("french") shells and BSC threaded steerers, tubing diameters are BSC: 28.6mm for down and seat tubes and 25.4mm for top tube

metric dimension bottom bracket cups should be a smooth mount unless threads have been damaged

BSC thread cups have a slightly smaller pitch diameter so and adjustable BSC cup can be started but will not go very far due to thread difference


-----