Jack And Jointer Planes

Posted by Easy WoodCraft on

Jul 25, 2016

Traditionally, a craftsman's jack plane and jointer plane were his bread and butter. With these two planes, he could take a rough sawn board and turn it into a straight board, smoothly surfaced on all four sides. The edges would be perpendicular to the faces, so the boards could easily be joined together to make larger panels. Although the electric jointer and planer have taken over these tasks in the modern shop, jack and jointer planes are still incredibly useful in the shop for surfacing a panel, jointing edges, and all around smoothing. If you've never planed a rough sawn board so that it's perfectly square, give it a try; you'll have a lot more respect for the cabinetmakers of the past.

Jack and jointer planes are very similar in appearance. The big difference is in the length of the sole and the width of the blade. Generally, the cutoff between a jack and a jointer plane is 18". Jointer planes begin around 22", and a mid sized plane, often referred to as a fore plane, resides in the no man's land between the two (see the chart below). Another common rule of thumb is: The longer the sole, the wider the blade but there are some exceptions to this.

Whether your plane is a jack, fore, or jointer. it will have similar parts. Older planes had wood bodies or soles, and modern planes have metal bodies. For a short while, "transitional" planes were made that supposedly offered the best of both worlds. (For more on this, see Wood and Transitional Planes in Using A Jointer Plane.)

One of the best ways to get familiar with a jack plane or jointer plane is to take one apart. Start by loosening the cap lock to release its pressure. Then slide the lever cap up and off the screw. Now you can lift out the blade and cap iron assembly. These two pieces are held together by a screw that can be loosened with the lever cap or a wide blade screw driver. Twist the cap iron, slide it over until it slips over the screw, and lift it off. The cap iron (also called a chip breaker) helps sever chips as they are lifted up by the blade; it also serves as a stiffener to help prevent chatter.

The cap iron and blade fit onto the frog a separate casting that's screwed to the body of the plane. On better planes, there's an adjustment screw in the rear of the frog that allows you to move the frog to open or close the throat opening.

The frog also houses the lateral adjustment lever that aligns the blade parallel to the sole, and the depth adjustment knob that raises or lowers the blade. A wood handle on the back and a knob on the front complete the plane.

The blades may be sharpened in one of three common ways: straight, convex, or with softened corners. Convex is useful for rough work, and softening the corners helps prevent them from digging in.

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