National Presto (NPK: 78.12*, -0.61, -0.77%) seems a bit like Acme from the Road Runner cartoons. It makes waffle makers, shoe polishers, military fuses and ammunition, adult diapers and plenty more (but not rocket-powered roller skates). The assortment might seem perplexing, but shareholders aren’t complaining. Presto has conjured a 51% stock gain over the past three years. The company owes nothing and, at $79 a share, holds more than $21 a share in cash. Sales and profits are rising, shares cost less than 11 times earnings and there’s even a dinky dividend — about 1.5%.