Buell gained notoriety at an early age as a counterfeiter by altering five-pound note engraving plates into larger denomination plates. His sentence was to be branded above the forehead under the scalp, loss of a portion of his right ear, and life in prison, plus forfeiture of all his lands and estates. Because of his youth, he served little time in prison and only the top part of his ear was cut off, but the authorities permitted it to be sewn back on. In 1765, Buell received a patent for a lapidary machine, making him the first Connecticut resident to receive a patent. After creating a ring on that machine, and presenting it to the prosecuting attorney, Buell's counterfeiting sentence was pardoned.