Compared to the original 1937 version, this 1941 pedestal countershaft shows evidence of material and time saving - as well as cost cutting - with the twin turnbuckles and over-centre locking cams replaced by just one combined push-bar acting against the centre of the unit. This was a perfectly adequate mechanism, of course, but the ability to slightly "skew" the line of the countershaft pulley to get the belt running exactly in line was lost. Also missing was a solid push on each side of the upright that previously had ensured the greatest possibly rigidity no matter which speed was in use.
Why was this done? In 1941 preparations were under way for the USA to join WW2 and many machine tools started to be turned out with a "war finish" (and often marked as such) with basic functions prioritised - 'perfect' being the enemy of 'good enough'.