We could use pool cues in Fallout 3, so I can't see why scythes and even brooms would be outta the question.
Yes fallout 3 had a nice collection of weapons, very few were effective but it looked fun.
The scythe is ineffective because the blade point the wrong way, yes it can be modified but then it would not work for cutting grass.
The pitchfork probably the tool who makes the most effective weapon, a metal spade or a pickaxe is also good even if heavy. A hoe can also do decent damage.
Chairs are shields not lethal weapons, brooms are not lethal, a frying pan should be pretty effective, even better if hot, boiling water or other hot liquids is the best weapon in a kitchen.
In short ignore anything that is less lethal than a dagger because everyone has one.