I am new to electronics, and I inherited a breadboard from my grandfather. I could fit 2.54 mm headers into it (as shown below):
I recently got a new breadboard, but the holes seem to be closer to each other, and the headers won't fit (shown below, on the left it looks like it lines up, but as it gets further to the right the pins are further and further from the hole):
I also got a compatible/clone Arduino Nano, which plugs just fine into my new (narrower) breadboard, but not my older (wider) breadboard (pictures below):
I measured the pitch and found that the old breadboard has a 2.54 mm pitch, but the new breadboard seems closer to 2.45 mm.
Is there more than 1 standard for breadboard and header pitch, or if not, what's going on???