Manufacturer functional interchange
Boston Gear F862BF/F863BF appears in the same manufacturer-published cross-reference row as David Brown M062(3)FAN at Match installed ratio/application · Boston 800 size 860 · Output flange mounted NEMA C-face.
Boston Gear publishes F862BF/F863BF for 800 Series size 860 in the output flange mounted nema c-face column of its in-line helical interchange guide. Boston states the 800 Series is designed to be functionally interchangeable with listed drives while requiring verification of ratings and dimensions.
The manufacturer describes the target family as functionally interchangeable with the listed competitor model or configuration.
David Brown M062(3)FAN and Boston Gear F862BF/F863BF are tied by the published source at Match installed ratio/application · Boston 800 size 860 · Output flange mounted NEMA C-face.
The source still requires ratings, dimensions, ratio, fit, and application conditions to be checked before ordering.