The steel saw is a weaker version of the auto axe, dealing roughly half as much damage. It appears to be a modified concrete cutter or concrete saw, with a rotating metal blade. Slaves use the steel saw for cutting through metal objects. However, this does not translate to an in-game damage bonus against robots.
The steel saw can successfully strike about 625 times from full condition before breaking.
Auto axe: A modified and stronger version of the steel saw made out of old car parts
Man Opener: A stronger variant that ignores armor (power armor included).