Are Toro Lawn Mower Blades Reverse Thread . Are lawn mower blade nuts reverse thread? Having said that the blades of a lawn mower would be reverse threaded. Are Lawn Mower Blades Reverse Thread? from lawnmowerguru.com However we may have to block the blade from turning in order to break the bolt loose. Just what does it mean to say that lawn mower blades are reverse threaded? Having said that the blades of a lawn mower would be reverse threaded.