Every once in a while I'll pick up a hand plane that I was just using and it will refuse to cut. If I'm working my way through a pile of stock, I'll assume the thing that's changed is the board. Maybe this particular piece is cupped or warped. So I advance the blade, thinking that I'll go back to a finer cut after I get the surface flat.
Usually I'm right. Usually the stock isn't flat and the coarser cut straightens the thing out. But I ran into a situation recently that has me checking for something else before I habitually advance the blade.
I was prepping a blank for a sliding deadman. I had already cleaned the thickness planer marks off one face and set the plane down to flip the board. The first face hadn't required any special technique. I just worked my way across the board and, after a couple passes, the face was clean. When I picked the plane up again to work the other side, I could only get it to bite on the ends.
I figured the part must have really bowed since I milled it up. I advanced the blade and it made almost no difference in the cut. I fought with this for too long before my brain started think about the problem in a different way. If the board was bowed than both faces would be effected. The first face had presented no challenges. That means I either pressed it flat while I was planing or I planed right over the top of the hump. The board was 1-1/4" thick, so I doubted I had pressed hard enough to make it lay flat. And now that the first face was lying on the bench, the board wouldn't rock. So it wasn't bowed.
I was at loss. So I went back to the basic premise of woodworking... "Sharp Fixes Everything." And as I was about to remove the iron from the body of the plane I noticed something.
The mouth was closed.
I don't know how it happened. Maybe I loosened the front knob when I set the plane down. Maybe I had bumped the toe of the plane on the work or the bench on my last pass over the first face.
I still sharpened the blade. I had, after all, driven edge into the mouth when I advanced the iron.
So now I have a new strategy for when my plane suddenly quits cutting. Instead of cursing it, I'll watch my mouth.