I need the belt size for a craftsman lt1000 42 inch cut model #917271815 sears is no help

Hi,
There is a reason, trying to save a dollar? Well, to replace it with a aftermarket belt of equal or better quality will cost as much or more than the OEM.
I know, I have seen the people who do not think "s..t" stinks for over thirty years. I have seen those who but a cheeap belt and wonder why five or six will not last as long as one of the "real" thing.
Anyway, it is an AYP 144959 by the original number and it crosses to 1/2" x 95 1/2" sheathed belt. The sheath and the fibers within the belt are what allows it to survive the rigors of running a deck.
Peace,
Clarke