Planer knives are the long sharp rectangular knives used in planer machines. These machines smooth and cut wood boards for woodworking. Most planers have multiple blades and various methods for tightening and removing them.

Planer knives should be replaced roughly once a year, but this depends on how often the machine is used and whether the wood you're cutting is clean. Paint, sand and dirt can all prematurely dull planer knives, so professionals working with reclaimed wood will have to replace them more often.

1. Improperly positioned planer knives can cause grooves and wave-like ripples in your wood when cutting. Always follow the manufacturer's recommended procedure when replacing blades.

2. Some planer knives are conditioned to last longer than normal. Often, you can find knives made or tipped with carbinide or tungsten that provide a longer blade life.

3. There are many different sizes of planer knives, so make sure you have the exact measurements of the blades you are replacing before ordering new ones. Planer knives information can usually be found in the machine manual or on the blade packaging.

Action Steps
The best contacts and resources to help you get it done

Choose a planer knives provider that sells reusable blades

Planer knives are available from many machining and woodworking stores, as well as some tool stores. Most sell a wide variety of lengths and thicknesses; but depending on your planer's model, you may have to order replacements directly from the manufacturer. Planer knives are generally available separately or in sets. What you get depends on whether you need to replace them all at once, or just fix one.

I recommend: Check out International Tool's planer knives list, or buy from Amana Tool.

Find a planer knives sharpening service

Sharpening services for planer knives vary from hand-sharpening to computer-calculated machine sharpening. If you're using carbonide tipped blades, its important to use a service that specializes in them, so that they can reapply the protective coating after each sharpening. Other blades generally sharpen best on diamond tipped wheels to prevent nicks. Some places even offer a perfect sharpening guarantee.

I recommend: Find planer knives sharpening services at Dynamic Saw's website, or check out the perfect sharpening guarantee from Burns Tools.

Buy disposable planer knives for quick replacement

Disposable planer knives are usually double-sided to provide the most use. Although they are generally not as high quality as reusable blades, disposable planer knives are cheaper and less hassle. When a disposable planer knife is nicked or dull, you simply reverse it and use the other blade. Once both blades are worn, you replace the blade with a new disposable. This saves the downtime you'd experience during sharpening shipments.

I recommend: Check out the selection of disposable planer knives at Sears, or buy from PlumberSurplus.com.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Sharpening planer knives can reduce the depth of your planer machine's maximum cut. Depending on how often you make larger cuts, this may be a problem. Those who routinely make large cuts may want to use disposable blades.