The clown's mini-chainsaw supposedly exists in three categories of items -- blades, construction, and toy. Luckily, there are three books that triple toughness of those item classes. Taken together, the small chainsaw becomes a very tough weapon (almost unbreakable). The books you want are in P101 (toy magazine), P108 (engineering book), and W204 (criminology book). Although you need to have four slots to make this weapon work, Frank will have a nearly unbreakable melee weapon for any mode.