How to Measure the Projection of Knobs

Cabinet and drawer knobs are more than a decorative touch added at the last minute. The size of the knobs will determine how well they are used. Width and projection of the knobs will help you decide if they are the right-sized accessories for your cabinets or drawers. The answer is not as straightforward as you might think.

Knobs project out from a surface for you to grab, making opening a drawer or cabinet easier. The drawers also serve as a decorative piece of hardware. Match the knobs to seamlessly integrate into your decor. With the wide variety of knobs available, finding one to match your space is easy, but before you buy, you need to make some measurements.

Knobs need to be proportionate in width to the surface on which they are installed. The raised portion around the border of the front of the cabinet where the knob sits is the stile. Knobs should not be wider than the stile because when pairs of cabinets are closed, the two knobs will hit each other, preventing the cabinets from properly closing. How far the knobs protrude also needs to be considered. In low-clearance spaces, knobs that jut far away from a surface can be hit by passers-by. They can also prevent a cabinet from being fully opened when the extra-long knob hits the wall.

The width of the knob will be the diameter of round knobs. Measure the knob across the widest part. According to the book "Woodworking Techniques: Best Methods for Building Furniture from Fine Woodworking" by Fine Woodworking, most cabinet knobs set in the stile are in the center of the stile, 2 3/8 inches to 2 3/4 inches away from the outer edge of the cabinet. This means that to keep the knob from hanging over the edge and hitting the knob of the adjacent cabinet in double doors, it should be no wider than 4 2/3- to 5 1/4-inch wide.

When installing knobs, the only part that is below the surface is the screw. How far the knob projects in front of the door is measured from the butt of the knob material to the farthest tip. This applies to drawer, cabinet and doorknobs. For cabinet and drawer knobs, a screw might already be installed inside the knob and attached through the front of the drawer, but some knobs have the screw inserted through a hole in the drawer into the back of the knob. In either instance, the screw for the knob must be as long as the sum of the knob's length and the width of the drawer or cabinet.