A Field Guide to Large Power Tools: Jointers and Planers
Both the jointer and the planer operate on the same principle: a series of knives on a roller pass over or under the surface of a piece of wood, taking off a tiny layer such as 1/32nd of an inch. Where they differ is in their purpose as well as the dimension of wood used in them.
You typically run the edge of a piece of wood through the jointer (on a 1×4, that would be one of the sides that is an inch). After wood has been through the jointer, that side is perfectly flat. You can then use it to rip the wood on a table saw with the flat side toward the fence. If you run a piece of wood with bumps in it against the fence, your cut will be inaccurate. Unfortunately, in woodworking, as in life, a small mistake or inaccuracy seems to multiply itself to the point of significantly affecting the final product.
In contrast to running the edge of a piece of wood through the jointer, you run the large surfaces through a planer. The planer helps you to make sure all the wood you are using in a project is the same thickness. If you want true accuracy in your projects and a professional look to them, a planer will help you with accuracy. Planers can also “flatten” small irregularities such as shallow grooves in wood.
Maintenance on both machines is similar; the most common job is to change the knives in the roller. Sometimes a piece of dirt or metal will nick a knife and you will see the evidence of it on the out table in the form of a little ridge. In that case, you can change the knives or you can shift one knife over to the right or left just a little bit so the nicks in the knives no longer line up. Changing knives is not too difficult; paying for new knives or for sharpening can be a challenge, so a lot of woodworkers learn how to sharpen their own knives.
As you can imagine with any tool that has multiple knives as part of its makeup, both of these tools can cause serious damage to the human body. It is important to use standard shop safety practices such as wearing safety glasses and ear protection as well as safety rules specific to these tools, found in the manual. Lost your manual? You can usually download a replacement from the manufacturer’s website.
Finally, these tools produce a lot of shavings! You will want to use some sort of system to keep them from spilling all over your floor.
If you have knocked together a few book cases and the like and are ready to move on toward a higher standard of woodworking, having a jointer and a planer will help you to take that next step.