How to Adjust a Carpenter's Jack Plane

Place the jack plane on a flat surface, and then look at how it is put together. Notice the one and three adjustment points on the plane. The primary adjustment that is necessary determines the depth of the cut. This is a knob with a threaded screw that holds the blade in place. A second knob is located behind the blade. This determines the angle of the blade. The third adjustment on some planes is a lever that controls the side-to-side angle of the blade.

Loosen the primary adjustment knob by turning it counterclockwise. This allows you to adjust how deeply the blade penetrates into the wood. Avoid attempting to remove more than 1/16 of an inch at a time. When the desired depth is set, tighten the primary adjustment knob.

Loosen or tighten the knob located on the backside of the plane, just underneath the blade. Turning the knob counterclockwise reduces the angle of the blade's cut, making the blade pass through the wood more easily. Turning the knob clockwise increases the angle of the cut, creating more of a scraping pass when the plane is used.

Set the blade angle adjustment at the top of the blade to its neutral position to create a straight cut in the wood. Move it to the left or right to angle the blade to one side or the other and create an angled cut in the wood.