It's the headstock angle. Wood is very strong along the grain you create an area that goes across the grain. Worse, it's thin there too. So it's just inherently weaker. If you see carved curved table legs you can find plenty where they snapped right at the bend too. Same thing. See the pic below, you can mitigate that but even the 'strong' one is weakest right at that bend. Fender just doesn't have an angle and of course maple is harder wood than mahogany but the key is the angle of the headstock creating a weak spot. The upside is that it puts downward pressure on the nut and theoretically yields better sustain as a result.
PRS split the difference between Gibson and Fender (which was their entire design philosophy) and so they have a mahogany neck and headstock angle that is more than Fender but less than Gibson. They don't seem to break. Gibson just pushes it to the limit.
Last edited: Nov 28, 2020
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