JOINTER Tune-Up

Simple steps that yield smooth, square stock edges

- Paul Anthony

The jointer is one of those “heaven or headache” tools. When it’s working properly, it makes quick, sweet work of straightening and flattening boards. However, a poorly-tuned jointer can cause no end of frustration, yielding crooked edges, weirdly tapered pieces, and washboard surfaces.

Though a relatively simple tool, the jointer requires an exacting setup. Fortunately, it’s not that difficult to tweak the tool into proper working order. All you need is a good straightedge, a simple shop-made jig, a few common workshop tools, an automotive feeler gauge, and a bit of patience. The set-up sequence involves checking the tables for flatness and parallelism, correcting them if necessary, and then adjusting a set of sharp knives to the proper height. The entire procedure should only take an hour or so, paying big dividends in accuracy and time saved down the line.

Check the tables

Make sure your outfeed table is set to its proper height in relation to the cutter head and knives. As shown in the drawing on the facing page, it should be level with the knives when they are at the top dead center. Check this with a straight piece of wood (about 1/2× 11/4× 18). With the machine unplugged, rest the piece on the outfeed table with about 2 extending over the cutter head. Rock the cutter head while adjusting the outfeed table until a knife just barely grabs the piece. Lock the table.

Check each table for flatness as shown. Humps or dips can compromise operational accuracy. If a tune-up doesn’t correct problems, it may just be time to invest in a better machine.