Tool Review: 6" Jointers
Some woodworkers consider a jointer a luxury. Rather, we call any machine that flattens faces and squares the edges of rough, warped, or oversize lumber a godsend. Sure, you can buy larger--and more expensive--jointers, but a machine that face-joints 6"-wide stock will satisfy most of us. With user-friendly options galore in this class, from long tables to spiral cutterheads to built-in mobile bases to power switches mounted on pedestals, buying a jointer can be more rewarding--and confusing--than ever before.
In our testing, those jointers with straight-knife cutterheads most often delivered perfectly flat, unblemished workpiece faces and edges. Granted, faster feed rates left scallop marks, but these virtually disappeared with slower feed speeds. On other models, high-speed-steel knives that conform to grooves in a helical head produced shallow grooves down the length of the workpiece, and the carbide cutters arranged in a spiral around the cutterhead created a similar pattern. Both of these surfaces required about twice as much planing, scraping, or sanding (compared to straight knives) to remove the linear striations. But the spiral carbide cutterhead blew away the field when we face-jointed bird's-eye maple. The remaining jointers showed at least 1/32"-deep tear-out.
You also have to factor in the cutterhead when figuring cutting power because spiral models with carbide cutters require greater oomph to power through cuts. (This happens because two to three cutters are always in contact with the wood; straight knives have intervals--albeit split-second ones--between knife cuts.) In our tests, four machines with 1-hp-rated motors held their own against two of the leading machines with 1-1/2-hp motors, and all six single-horse models outpowered the model with the spiral carbide cutterhead.
Ultimately, it becomes a question of which matters most to you: cut quality or time. With a jointer you can compensate for a lack of power with shallow cuts and slower feed rates. But you can't compensate for average to poor cut quality; all you can do is smooth it afterward with other tools.
• Beds and fences. To create flat surfaces on hardwood and softwood, a jointer must have dead-flat tables that are parallel with the knives (front to back). We found all within .0025" of perfectly flat. So, no problems there. For setting the height of the outfeed table we prefer a handwheel for its ability to make finer adjustments. An outfeed table set lower than the knives results in snipe, a scooped cut on the last inch or two of the workpiece. Levers and handwheels work equally as well on the infeed table, where adjustments determine the depth of cut. If you work often with 6' or longer stock, and have room in your shop, buy a jointer with a long bed. This enables you to work more accurately and safely with longer boards.
Greater length also comes in handy with fences. The tested models measured between 29" and 35" long. The "worst" three fences measured about .006" out of flat (bowing away from the cutterhead), but again it was no problem. (A fence more than .010" out of flat would need to be machined, if possible, to straighten it.)
• Mobility. Because these machines weigh 200 lbs or more, built-in mobile bases on some models come in handy when you need to move them. Adding an aftermarket mobile base adds $50 or more to the price of other jointers.
Top Tool: Grizzly G0604X
Top Value: Ridgid JP0610
Learn the complete results of our testing of the Craftsman 21705, Delta 37-275X, General International 80-075L M1, Grizzly G0604X, Grizzly G0452Z, Jet JJ-6CSX, Ridgid JP0610, Rikon 20-110, Shop Fox W1745, and Sunhill SM-150 in the March 2009 issue of WOOD magazine, or download the review.