Covering or removing a knife for the blessing after meals

Hi,

There is a practice of covering or removing knives from the table when reciting the birkat hamazon blessing after eating a meal. Various explanations are offered, including the idea that the table is like a mizbeiach [altar] when one gives from his food to the poor, and just as a mizbeiach may not have a blade upon it, so one's table should not.

The reasons that are suggested for this practice do not seem to apply to a snack, and so one would not need to cover or remove knives when reciting the al hamichyah or borei nefashot blessing after a snack.

(Rivivot Ephraim 1:136:2)

Have a great day,
Mordechai