We present the design, construction, and simulation of a simple, low-cost external cavity diode laser with a measured free-running frequency drift rate of 1.4(1)~MHz/h at 852 nm. This performance is achieved via a compact, nearly monolithic aluminum structure to minimize temperature gradients across the laser cavity. We present thermal finite element method simulations which quantify the effects of temperature gradients, and suggest that the drift rate is likely limited by laser-diode aging.
