Jointer vs Planer

Beginning woodworkers all ask this basic question; what is the difference between a jointer and a planer? The answer is simple… a lot! Each machine does a completely different surfacing operation. A jointer flattens a face or straightens and squares an edge, and a planer thicknesses wood. Whether you need one, the other, or both can easily be answered by knowing how they work, what they do, and how much wood surface preparation you pay your lumberyard to do for you. And honestly, you probably could be a great woodworker without either machine. They are just time savers. Heck… You could use hand planes! Ultimately, you need to convert your wood stock to usable pieces for your projects. A jointer and a planer will help you get there.

Jointers work this way: There’s an infeed table and an outfeed table. The tables are aligned in the same plane. A cutter head with knives is mounted between the tables, and its cutting circle (tops of the knives) is aligned flush with the outfeed table. The infeed table is lowered to a depth equal to the amount of wood you want to remove. Passing a board across the running machine (with guard in place) removes the wood, and the cut portion of the board is then supported on the outfeed table. A fence is used as a guide when flattening a face, and as a support when jointing board edges. The fence is adjustable for different angles, typically up to 45-degrees.

What a planer does and how it works. A planer is used to make a board that’s been jointed flat equal thickness from end-to-end. Mechanically it’s more complicated than a jointer, but functionally it’s simpler. A flattened board is placed on the planer table (bed) and pushed in. The machine’s feed roller grabs the board and pulls it through and past a rotating cutter head set above the bed, which removes wood. The distance the bed is set from the cutter head is the resulting thickness. All planers have limits to how much wood they can remove in one pass, so to achieve your finished thickness will likely require multiple passes.

Different levels of lumberyard-produced surface preparation.

Your lumberyard can do none, some, or all of your required surface preparation to the boards you purchase. The more they do, the more it costs, and the less control you have. You could take this to the extreme, give them a cut list, have them size all the pieces, but you’d go broke and have no fun woodworking. I’ll start by telling you how both machines are used to surface rough lumber, and then give three more scenarios where your lumberyard does increasingly more of the work for you.

Rough. I buy my lumber rough (no surfacing), or surfaced hit & miss, which is how almost all the lumber I buy today comes. That removes 1/16” and planes the wood so it’s easy to see the grain and color. The pieces I need for my projects are “inside” the boards I buy, and I have to machine the boards to make my pieces. I have much greater control over the shape and flatness of the wood I use when I machine a rough-cut board just prior to using it in my project. One thing is for certain with surfaced wood… it will not be the same size and shape tomorrow. Sizing rough lumber requires a jointer to flatten one face, and a planer to cut the thickness. To cut the width you use a jointer to square and straighten one edge, and then rip the width on a table saw. I rip my boards 1/32” wide, and then joint off the last 1/32”. See my article “9 Steps to Sizing Rough Lumber” Click here.

Surfaced Two Sides (oversized)- S2S. Example: You ask your lumberyard to surface your 4/4 boards to 13/16” even though you know you will eventually use them as 3/4” thick boards. They surface the boards using a doubled head planer that cuts both faces at the same time and does a pretty good job of flattening. Doing the surfacing this way can save you a lot of time. Then just prior to using your boards in your project you will “kiss” the boards down to 3/4” to clean up any rough surfaces left from the lumberyard machining, remove any dirt and oxidation that might have accumulated over time, and provide a fresh surface, which is critical for gluing. With this type of surfacing you’ll need a planer for final thicknessing, and a jointer to straighten edges.

Surfaced Two Sides (final thickness)- S2S. All is the same as above but this time your lumberyard surfaces your boards to their final thickness. All you need now is a jointer to straighten edges.

S2S with Straight Line Rip - SLR. All is the same as S2S but this time your lumberyard cuts one edge of every board straight and square. You can now mange without either machine, but even so, having a jointer to remove saw marks and smooth edges is nice.

Conclusion: A jointer can be used to make a board’s face and edge straight and true.  A planer makes your boards uniform in thickness, with two parallel faces. The operations aren’t interchangeable between the two machines.

Owning both machines gives you the greatest control over the flatness and smoothness of the wood you use in your projects. My jointer is a monster at 12-in. wide and 84-in. long. It’s really nice for flattening long and wide boards, but may be overkill if your projects will be small. My planer is 13-in. wide making it the perfect companion to my wide jointer.