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Quick, what's the most important stationary shop tool? The tablesaw, of course. Nothing else on the planet offers the same mix of versatility and accuracy for general workshop cutting tasks. And the new breed of high-performance benchtop saws also deliver portability, while still retaining the torque to glide through 2 oak. Impressive. But as useful as they are, tablesaws don't come ready-to-use. Planers, jointers, drill presses and sanders are all set to go soon after you've torn off the cardboard shipping box, while at this same stage tablesaws aren't even close. Why? Simply because so many subtle interactions have to work in harmony for a tablesaw to sing sweetly. Now don't get mad at the factory folks, they can't help it. Tuning up a tablesaw demands quite a few interrelated adjustments that take lots of time and finesse; adjustments that could be easily thrown out of whack during the boat ride from the factory, the truck ride to the wholesaler, and the car trip to your shop. Helping a tablesaw to live up to its potential is your job. Here's how to do it.
The Easy Stuff
Knock off the simple things first. This means adjusting the height of the throat-plate and any metal outfeed wings so they're flush with the surface of the main table, as shown to the right. Adjustment details vary, but your aim is always the same: to arrange the separate parts of the saw's work table so they're all flat and even. If the throat plate sticks up higher than the table, for instance, wood will catch during critical phases of each cut. Droopy outfeed wings, on the other hand, mean wide workpieces may sag during a cut, causing blade binding and inaccuracy. Use a metal ruler, the edge of a cast aluminum carpenter's level or an edge-jointed piece of wood to gauge how evenly all tabletop parts line up. Most saws require Allen keys, open-end wrenches or a socket set to tweak these parts.
Now's also a good time to lubricate any levers, wheels and knobs with light machine oil, and treat the table with a coat of paste floor wax. Wax is my choice of lubricant for the fence support bars, too. Getting your saw's parts to operate smoothly is 50% of the tuning job, and this depends on thorough lubrication.
Making the Blade Behave
The heart of any tablesaw is its blade, and how your saw holds a blade and responds to adjustment is critical. It's possible to spend astonishing amounts of time measuring and tweaking blade run-out -- the degree to which rotation deviates side-to-side from a single plane. But from what I've seen, this job isn't something that most workshoppers need to do. Unless there's something dreadfully wrong, you'll do just fine making sure the blade is square to the table when the angle scale says it is, and the height and angle adjustment mechanisms are well-lubed. To check the blade angle (and similar settings on other machines), get yourself an all-steel machinist's square. The 4 size is good.
Nothing else offers a more accurate, more stable reference for the all-important 90 degree angle that woodworking is based on. |
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A gem like this won't go out of whack and is also great for checking the edges of jointed boards.
Fence Finesse
The most important part of tablesaw adjustment is getting the fence and blade parallel. This is also the most likely source of trouble. A fence that isn't parallel to the blade always leads to burning and splintering as wood is forced into the side of the spinning blade. A tuned fence, by contrast, prevents the workpiece from ever touching the side of the blade. The difference between a good fence and a bad one is how effectively it'll hold a parallel adjustment as you slide it across the saw table, lock it, unlock it, and slide it again during day-to-day use. It's actually quite an engineering feat to build a fence that both slides well and returns to a blade-parallel position on its own every time, and every place, you lock it down. That's why the best fences are made by specialized manufacturers that usually produce nothing else. The quality of factory-supplied fences varies a lot, and inexpensive saws generally have pitiful fences that either make you laugh when you see them in stores, or yell like a crazed maniac when wrestling with the one you have the misfortune of owning.
Tablesaw fence adjustment is a two-part process. Initial work begins after you've installed your best blade, then adjusted the tilting mechanism so the blade's square to the table and raised as high as possible. Next, cut a scrap wood measuring stick about 3/4 square and 8 to 12 long, then slide and lock the fence so the ends of the strip are snug between the blade's teeth on the left, and the fence on the right. Be careful not to bend the blade to one side as you do this. Now with the fence locked, pick up the wooden gauge strip and use it to check the same fence-to-blade distance at the back of the blade, just as you did at the front. How does it look? Every fence has an adjustment bolt (sometimes near the locking lever, sometimes at the far end) that can be loosened to allow the fence to be angled one way or another, independent of the locking mechanism. Arrange the fence so it's parallel to the blade, lock it down, and test again.
The second part of fence adjustment involves trying the saw out. Get a scrap piece of wood, then adjust the fence to allow a random cut somewhere down the middle. Halfway through the cut, switch off and let the blade come to rest. Is the body of the saw closer to one side of the saw kerf or the other? A little bias towards the left side of the cut (that's usually the waste side) is fine, but no part of the blade except the teeth should be touching either side of the cut. Spin the blade by hand and listen for periodic contact as it rotates slowly.
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