There are five cures for tearing:
- Reverse the direction of planing.
- Sharpen the blade.
- Take a very fine cut.
- Set the cap iron very close.
- Close up the mouth.
Anyone of these or a combination of any number of them will prevent tearing. On the other hand, too close a cap iron and too fine a mouth will cause “clogging.” It is always worth examining the mouth as this may be poorly formed or obstructed by a blob of paint, which can be removed by gentle filing.
– Robert Wearing’s “The Essential Woodworker”