I want to make a one handed shovel for my college project. I have thought of substantial modifications from what has been described here.
The idea has already been described in patent US646472.
Will I be infringing any rights?
The broad idea of a "one-handed shovel" is not preempted by the patent. The patent only protects what is described in the claims.
Also, it appears you mis-typed the patent number,as that patent has nothing to do with a one-handed shovel, and would have expired about 100 years ago.
In general, though, just because a use is "non-commercial" is not a great defense to infringement.
Spoons are one-handed shovels. And off-patent. Whether you would be infringing ANY in-force patents with something more complicated, like 6464272, is a complicated question that might take many hours to answer, and then the answer would never be definitive. That's life. But unless you sell a million on the internet, it won't make economic sense for any patent owner to sue you.
If you were trying to refer to:
One handed shovel for handicapped
Google patents says it expired in 2006 due to non-payment of maintenance fees.