12-inch Limit on Planers
Issue: Issue 104
Posted Date: 7/26/2004
Q. I have a 12-inch planer. I have read that you cannot plane boards that are shorter than 12 inches. Is there a recommendation or requirement on the shortest length that one can run through a planer? If so, could one make a jig to hold shorter pieces of wood and run it through the planer? The reason I want to plane the smaller pieces is that I have a large quantity of maple, birch and pine slice that I want to use in scrollsaw work but need to plane them down to proper thickness, and want to use the planer. Any suggestion will be appreciated.
Michael Dresdner: "Good question, and the good news is there is a yes answer. First, let's look at why short pieces won't work, and then the solution will make more sense.
"A planer has two pressure rollers, one in front and one behind the cutter. These rollers hold down the board while it is being cut. If the board is short enough to fit in between the rollers -- so that it is not being held down by either when it is being assaulted by the cutter head -- it will be picked up and shredded, or possibly thrown back at you. The spinning cutter head creates a slight vacuum, and will lift a small piece of wood into its path. You can imagine the result.
"The solution is to attach longer outriggers of scrap wood to either side of the board. You'll end up with an H shaped unit, with the short board forming the cross of the H and the grain going the same way as the grain of the long outriggers. The planer will cut the outriggers as well, but they are scrap. More importantly, it will allow you to plane short pieces. Gluing them on is the simplest - you can cut them off once the board is thicknessed - but if you decide to use mechanical fasteners, such as screws or staples, make certain that you do not cut into the area where they are. Planer blades don't like eating metal."
Rick White: "The reason you don't go much shorter than 12" is so you have enough material on either side of the blade do you don't get kickback. You could make a sled or saddle, similar to what Michael describes, to run through the planer. Or, if it's only 3" pieces you're thinking about running through your planer, I'd try to figure out how to use my table saw or band saw instead - there might be other ways to resaw these pieces to get the right thickness. If your piece was small enough, you could make the sled and use a belt sander to bring it down in size."
Linda Haus: "One way to achieve this would be to put short dowels or biscuits between each small board to attach them before you run them all through the jointer together - that would be a neat little trickery. You wouldn't need very much glue, just a little dot to hold them together so you could break them apart again where you needed to. Or you could just cut the small pieces apart again."