A multi-industry industrial company, an aerospace supplier, and a building materials company all look like good values now.3M (MMM 1.64%), Carpenter Technology (CRS -1.36%), and Owens Corning (OC -0.32%) are vastly different stocks, but all three are attractive on a risk/reward basis. They each have a different investment case, so let's explore why they might suit a value investor's portfolio.3M is undervaluedThis industrial giant isn't the highest-quality company out there. After all, mediocre growth, decl ...