taken from
http://www.ladyoftheearth.com/stories/household-lore.txt
"Knife
In previous centuries a knife was a very personal possession, carried at all
times by its owner and used for hunting and work as well as cutting food. A
steel knife was regarded as being protection against fairies and curses; a house
could be protected by a knife being thrust into the door and a baby protected by
a knife stuck into the headboard of its cradle. A knife could also be thrust
into the mast of a boat for luck, although the word 'knife' was never spoken at
sea.
If two knives are crossed accidentally at the table it means bad luck or
quarrels unless one of the knives is immediately straightened. A knife falling
to the ground means the arrival of a male visitor. A knife with a white handle
could be used to divine whether the inquirer's future spouse would be fair or
dark; the knife was spun round, and if it came to rest with the handle pointing
towards the inquirer, the spouse would be fair; if the blade pointed at them,
the spouse would be dark.
The most common belief about knives is that a knife given as a gift will sever
the love or friendship between giver and recipient; a knife should never be
taken without something being rendered in exchange, generally a penny or other
small coin."