This comes up periodically
There are lots of old galoot tales:
*They're there to hold a tooth guard on.
*They can be sharpened to start a cut (why this would be easier than the traditional pulling back of the saw is not clear to me).
etc.
My theory is that they exist so people will ask why they exist, but that's a bit tautological and so probably not true.
I'm told Henry Disston himself said, more or less, that they were the fashion, so they put them on. They do add a nice fillip to the end of the blade.
Thanks for the information
I appreciate your speedy replies.
Now that I know what it is I will keep my eyes open for them......
Thanks,
Modern usefulness of saw nibs
David Gilbert's post reminds me that saw nibs do serve a useful purpose in modern life: the nib serves as the quickest way to spot an older saw at garage sales.
Just as the full oval tote on a metal bench plane serves as the immediate clue that the plane is worth picking up for further inspection.