Myford Screwcutting Gearboxes. There were two versions of the box: the earlier had a train of external gears under a detachable cover on its right-hand face, the later version was entirely enclosed. The gears and settings for each box differ and this publication contain both editions with full details of the metric conversions sets needed, the metric screwcutting charts for both boxes, how to mount the gearbox and other essential information. The manual for the later box also has charts for BA and MOD pitches. Both boxes can be fitted to either the ML7 or Super 7 - the only difference being the shape of the changewheel guard.