Evidently, some of the folks who hang drywall in Europe are not satisfied with mere utility knives. Why? I can’t say for sure because I don’t speak German, can’t read Czech, and understand only a smattering of French. No matter; I watched the videos below and figured out the following things about this most bizarre saw from Mafell.

a) There are applications where the preferred method is not to butt drywall at outside corners but to cut v-grooves in the back and then bend the board around. Why? I don’t know – maybe they don’t like corner bead in Europe (see first video below). Or maybe they are hanging some special kind of board where you don’t want to cut through the face paper.

b) If you want to bend drywall around a tight corner kerf the back. I knew this from bending wood but with drywall it’s hard to do—unless you have a saw that will cut it. The nice thing about doing it the way it’s shown on the video on this page (at about the 3:50 mark) is that it cuts more than one kerf at a time, the track gives you nice straight cuts, and the vacuum collects all the dust.

c) As a carpenter I can relate to putting a molding head on a saw and using it to cut v-grooves, dados, and rabbets in wood—enough to overlook the fact that its being described to me in French by some dude wearing a dress shirt and a bunch of rings. Still, wouldn’t it be easier to just use a router? (See second video below)

Don’t worry about the language thing when you watch these videos. If you know tools and construction you’ll figure it out. I showed these to a carpenter friend and he said WTF—which I think means something in German or Czech. But it could be French.