Silent star Fatty Arbuckle roams the screen like a sophisticated baby: sometimes half-asleep or innocently malevolent, more often well-meaning and determined, though with a core passivity that keeps his nobler impulses (typically toward some waifish ingenue) from getting the best of him. From 1917 to 1920, a popular series of shorts teamed Arbuckle with Buster Keaton (already aiming at his ideal persona). Each comic spins in private circles of ingenious organization and fleeting pleasures; when they share the screen, they collaborate warily, then let everything rip, contriving and curing epic-scale calamities.

At the Somerville Theatre this Saturday, the Alloy Orchestra will perform live with three Arbuckle-Keatons: "The Bellboy," in which the comics cut up at a fleabag hotel; "The Garage," in which, as grease jockeys, they spoil a couple’s woo-pitching session; and the Pirandellian "Back Stage," in which they play stagehands who take over a small theater when the actors quit. Alloy’s percussive scores emphasize the films’ machine-age clatter and rambunctiousness while also doing justice to their immense delicacy.