You are planing a curly maple panel with a sharp iron and it is tearing out anyway. The grain reverses under the blade and lifts a chip before the edge can sever it. You stop, look at the surface, and start thinking about the bevel-up plane in the catalog. The one set up for high-angle work. The one that is supposed to fix exactly this.
Put the catalog down for a minute.
The plane in your hand already has the part that solves this. It is the cap iron, the chip breaker, the second piece of steel sitting on top of the cutting iron. Most woodworkers set it once at a millimeter or two from the edge and never touch it again. Set close to the edge, it does the same thing a high-angle plane does, by a different route.
Here is the number, because a number is the only thing worth keeping from this. A chip breaker set 0.1mm back from the cutting edge gives you the tearout protection of a 60-degree plane. Set it back to 0.2mm and you get the equivalent of 55 degrees. That is not a rough comparison. It comes from measured cutting-force work, and the two methods are reaching the same place: they stop the chip before the crack ahead of the edge can run.
So the figure in front of you tells you where to set. Moderate stuff, ordinary reversing grain, comes clean at 0.2mm. Strong figure, hard curly maple, interlocked grain, wants 0.1mm. Only the extreme cases, burl and badly interlocked tropicals, need more than the cap iron can give, and that is a different note about back bevels and scrapers. For the panel that is actually giving you trouble most days, the answer is on the dial you already own.
Setting it is the part that takes nerve. 0.1mm is close. It feels like one fat shaving away from a jam, and the first time you set it that tight you will be sure you have gone too far. Pull the iron, set the cap iron down near the edge, sight the gap against light or a loupe, take a test pass on a scrap of the same wood. If it clogs, you are too close or the cap iron is not seated flat. If it tears, you are not close enough. It is a feel you pick up in about twenty minutes of fiddling and then have for good.
Now the part the catalog leaves out. The cap iron is not a poor substitute for the expensive plane. At the same tearout protection, the chip breaker takes about 30 percent less force to push than the high-angle cut does. Less force, same clean surface. You don't need a new plane for this. That is not a position. It is just what the numbers say.
One honest boundary. If your plane is bevel-up, none of this applies. A bevel-up plane has no cap iron, so cutting angle is your only lever and the high-angle iron is a real answer for you. The chip breaker route is for the bevel-down planes, which is most of the planes on most benches.
So the next time a panel tears, go to the bench before you go shopping. Pull the iron, set the cap iron to 0.1mm, sight it, test it on a scrap. If it solves the panel, you have saved yourself a plane and learned the most underused adjustment on the tool. If it doesn't, the catalog will still be there.