Fiberglass insulation hole cutter

[gatz]

Years ago, I was faced with the problem of cutting down the width of fiberglass batting for a 2nd story bedroom.
The local hdwe store only had widths that didn't fit the spaces between studs/rafters. No big deal, right? just trim 2" off the side, right?
Scissors and shears did NOT work worth a darn as the batting would bunch up, and make it near impossible to cut.

After some serious thinking (?) a truely aha moment came.
(1st, check to make sure the wife wouldn't see)
Grabbed the electric knife from the kitchen and gave that a try. Couldn't believe it, that worked like a hot knife through butter.
Took just a few moments to trim the excess away.
The opposing blade direction is what makes it cut so easily. This is along the lines of how the "nose hair trimmer" works without pulling hairs.

Now, if someone could apply the counter-rotating principle to a hole cutter to cut fiberglass, they may be on to something.