a saw includes a surface defining an opening therein , a plate structure configured to be attached to the saw below the surface , and an arm attached to the plate structure about a first shaft . a blade is configured to be engaged with the arm at a location spaced from the first shaft . the blade extends through the opening when the saw is in a normal operating position . the saw includes a firing mechanism including a barrel end portion having a bore defined therein and an extendable piston at least partially positioned within the bore . the barrel end portion is attached to the plate structure . the extendable piston engages the arm during its extension and causes the arm to pivot about the first shaft when the firing mechanism is activated by an activation signal . the pivoting of the arm causes the blade to be moved downwardly below the surface .