How to use a wood jointer

The critical part of using the wood jointer is making sure the blades are set at the same height as the outfeed table or, for best operation one- to two-thousandths of an inch higher.

A wood jointer is used to create accurate dimensional boards, creating finished board from cheap lumber or even recycled material. Here’s how to use a wood jointer to get the best results.

With a wood jointer you can create an absolutely flat surface and a true vertical edge before the piece is put through the surface planer. The surface planer then takes over making the other surface of the board absolutely flat so the top and bottom of the board are identical.

Using a wood jointer

A wood jointer is relatively simple to set up and use. Jointers are usually 6- or 8-inch tools, determined by the width of the cutting head. Generally, the 8-inch jointer is regarded as the more useful but it is more expensive. There are bigger machines as well, but they start to become prohibitively expensive unless the work you do justifies the investment.

The jointer has an infeed table and an outfeed table set at different heights. The difference determines the depth of cut.

The critical part of using the jointer is making sure the blades are set at the same height as the outfeed table or, for best operation one- to two-thousandths of an inch higher. This is best done using a straight edge. Place the straight edge on the outfeed table and rotate the drum. The knives should just brush the edge, and as a blade passes it will slide the straight edge slightly. When this movement is just 1/8 inch, the blade height is correct.

Align the fence so it’s at right angles to the feed tables. This can be done with an engineer’s square. Position the square next to the fence. If you see any light, it’s not square. Adjust the fence and recheck. Once the fence is set and the table height is correct, leave these adjustments alone unless you need to angle the fence to make an angle cut or replace blades.

As with the hand planer, the ideal cut with a jointer is 1/16 inch or less. To achieve this, set the infeed table using the gauge on the jointer.

Then, before you make a cut, inspect the lumber you’re jointing. If it’s cupped, put the concave side down and note the direction of the grain. Feed the piece into the jointer cutting with the grain as this will minimize any tear-out of the surface. Mark the surface you’ll be cutting with pencil or chalk, then continue making passes until all of the marks are gone. At that point your surface is true.

You’ll be creating the flat face on the piece on the outfeed side. Use a push block to hold the cut face down tight to the outfeed table surface. Use another push block or push-stick to feed the board. Only push with blocks over the cutter, never with your hands. If the board kicks out, your hand could drop onto the cutter.

Always use push blocks and push sticks when using a jointer. Never walk away from a jointer unless the drum has stopped spinning.

How to use a wood jointer safely

Planers have fast-spinning drums with exceedingly sharp blades and jointers should be treated with extra caution. Keep hands well clear of the spinning knives. Use eye and ear protection.

Never wear loose clothing or anything around your neck like a dangling pair of spectacles when operating a jointer. Always use push blocks and push sticks. Never walk away from a jointer unless the drum has stopped spinning.

–By Steve Sturgess, SteveSturgess.com