Stop cuts are one of, if not the most, basic and useful cuts a wood carver makes. First, "what is a stop cut"? A stop cut is a cut that is used to create a hard line, that will "stop" the knife from going further, hence the name stop cut. Lots has been written about stop cuts, but not too much on how to make them safely in smaller and/or rounded pieces. Some directions on making a stop cut suggest using the tip of the knife. This is well and good for some areas of wood carving (chip carving), but should not be universally employed. Lets say that you need to make a stop cut around a piece of smaller rounded wood. The safest way to do this stop cut is to use the length of the knife blade rather than the point. And In my opinion you should hold the knife firmly, applying pressure with the blade against the stop cut line and turn the wood into the knife blade. The following photos attempt to illustrate this stop cutting technique.
Photo 1: Penciled line where stop cuts goes.
.Photo 2: Place knife blade on penciled stop cut line near the tip of the knife blade.
Hold knife firmly with some pressure and "roll" the wood into the knife blade.
Photo 3: Never use the tip of the knife blade to make the stop cut on a curved surface of the wood. If you do, the knife blade under the pressure to make the stop cut may exit the wood at the edge and----well in this photo, my leg is right in the blades path.
Photo 4: Here's an application of this stop cut technique. This is a simple Santa, and the first stop cut is at the bottom of Santa's cap. Plunge the knife tip into the wood as shown, and while holding the knife firmly."rock" the wood into the blade following the stop cut line at the bottom of the cap. Continue rocking/turning the wood into the blade all the way around the cap's bottom. You may have to reposition the blade from time to time as you"run out of blade".
I would never use the knife blade like a pencil and try to make the stop cut in rounded wood by moving the knife blade to achieve the stop cut. By moving the wood instead of the knife blade you lessen the chance of the blade going off the edge of the wood. It's when knife blades go off the edge of the wood that something else gets cut.