diston hand saws

I own two, my grandfathers (he died 1952 at the age of 84) so they are quite old. One is a 'panel' saw the other a rip. Both still have the flexibility to fold the blade into the handle and spring out straight as a die. My problem is that the 'panel' is getting very difficult to sharpen - I have broken two teeth on setting it last time.
Q. can anyone identify these saws if I post more details?
Q. any ideas as how to get past the sharpening problem (I can wear out three files)

Dave,
For identification try vintagesaws.com web page or the disstonianinstitute.com web page Vintagesaws.com also has a great section on sharpening and setting. Your sharpening problem could be related to the brand of file you are using.