Interference lithography (IL) has proven itself to be an enabling technology for nanofabrication. Within IL, issues of spatial phase distortion, fringe stability, and substrate development have been explored and addressed. However, IL tools are still unnecessarily expensive, large, and complex. To address these issues, the authors previously built a simple IL tool that used a blue laser diode to produce ∼300 nm pitch structures. The resulting patterned areas (∼mm2) were limited by both the temporal and spatial coherence of the laser. Here, the authors report on the advancement of their low-cost interference lithography tool that makes use of newly available blue laser diodes and a simplified spatial filter to print larger-area (∼cm2) patterns. With this configuration, the authors have designed and implemented a small-footprint (∼0.2 m2) Lloyd’s mirror IL tool that can be assembled for less than ∼6000 USD.