Specialized tools for cutting and cooking potatoes have been used at least since the 1870s. Cranked slicers made continuous curling ribbons of raw potato; these tools appeared around the 1860s–1870s. Peelers similar in design to apple parers came out in about 1874. Chip slicers, dating to the same period, held a raw peeled potato against a revolving cutting blade. Beetles, wooden pestlelike pounders, are the oldest tool for mashing cooked potato, undoubtedly in use since Americans first grew potatoes. Other beetles of the 1870s have wire or perforated metal heads. A conical sieve, in which a cooked potato is rubbed with a wooden pestle through the holes, also dates to the 1870s. Potato ricers came in two types: a tabletop style with legs (ca. 1900) and a handheld press (ca. 1940) that forced cooked potato through a perforated hopper to create rice-sized potato pellets. An 1890s metal rack had folded prongs that pierced potatoes and directed heat toward their centers to speed the baking. Similarly, about 1950 folding racks with thick aluminum nails began to be used; each rack held four potatoes. Stovetop ovens in the 1940s had a built-in thermometer set directly over the burner, and baked potatoes twice as quickly as the stove’s oven.