Board Thread:General Discussion/@comment-14610890-20140418234901/@comment-3146930-20140421220815

Normally Toph has to be close enough to the metal in order to bend it however. Physical contact works the best, but I don't think she can bend metal at a longer distance. There is one big differences between the way they bend metal. Pyrrha is able to control metal using magnetism, but Toph can only control the imperfections in the metal in order to bend it (the small fragments of earth that weren't removed during the refinement process). However as seen in the Legend of Korra, purer forms of metal can't be bent. Considering the technology level of the world of RWBY, I'm sure Toph wouldn't be able to bend anyone's weapon.