A lot of products that we take or took for granted are now made in China or other Asian countries. Besides their varying quality control, from great to dismal, they also use a different measuring system than we do / did.
In other words when we designed something made to Inch standards they use metric. A lot of times rather than fractionize their metric measurements to make the part exact, they just round it up or down to the next increment.
So their parts are not always the same measurements as the original.
Usually they are close enough to fit and work, sometimes not.
Joe