Popular Woodworking 2003-04 № 133, страница 40

such saws have a cut-depth adjuster; you set the cut depth (with some trial and error), then "waste" each dado with kerf after kerf.

It's one of those operations you do once, just to try it. And once was enough for me. I prefer to stick with my table saw and my router for cutting dados.

Table-saw Dados

Let's look at the table saw first. It's powerful and equipped with accessories - a rip fence and a miter gauge - useful in positioning cuts. Like a lot of other woodworkers, I use a shop-made cutoff box (instead of the miter gauge) for crosscutting - it also works for dados. To use the saw effectively for dadoing, you need a dado cutter, either a stack set or a wobbler.

You can waste a narrow dado pretty quickly with whatever blade is on the saw. If you've got a manageable workpiece and just one or two dados to cut, you make five to seven kerfs to form each one. But to cut a cabinet's worth of dados, use a dado cutter.

If you're making cabinetry assembled with through-dado joints, you can knock out a lot of consistently sized and placed cuts in short order. What isn't necessarily quick and easy is achieving the precise width of cut you want. Stack sets, which give the cleanest cut, consist of separate blades and chippers. You have to select the combination needed to produce the approximate width of cut desired. To tune the cut to a precise width, you insert shims between the blades. It's got more trial-and-error in the setup than I like.

Some woodworkers (those with too much time on their hands, I think) make a chart or a cut sample with notes on the combinations of blades, chippers and specific shims needed to produce common-width dados. If you have the patience for this endeavor, my hat is off to you. Go for it.

But the woodworkers most likely to use the table saw for dadoing are those who are looking at a lot of cuts and not a lot of time to make them. Often, these folks adopt workarounds to avoid protracted setups. They'll shoot for an undersized dado, and then plane or sand the part to be housed in it to fit. Or they'll use the dado-and-rabbet joint: The mating part is rabbeted to form a tongue that fits whatever dado has been cut.

How do you locate and guide the cut? The rip fence is seductive, because it allows you

to locate a cut consistently on both sides of a cabinet or bookcase. It eliminates the need for layout. But it isn't a crosscutting guide, and dados are crosscuts.

Of the two cross-cutting guides, I prefer the cutoff box. It's built specifically for right-angle cuts and rides in both miter-gauge slots (instead of just one). In addition, it effectively immobilizes the workpiece, because the box is what moves, carrying the stationary work-piece with it. The work doesn't squirm or twist as you push it into the cutter. Fit the box with a stop so you can accurately and consistently locate a cut on multiples without individual layouts.

Stopped cuts can be problematic, and blind cuts can be downright hazardous. Because the work conceals the cutter, and because the cutoff box conceals most of the saw table, it's tricky to determine where to stop the cut. One good option is to clamp a stick to the outfeed table that stops your cutoff box at just the right spot.

A blind cut would require you to drop the work onto the spinning dado cutter. Not a routine that I'd recommend.

Any stopped cut done with a dado head will ramp from the bottom of the cut to the surface. You can leave it and simply enlarge the notch in the mating piece, but in so doing, you sacrifice the strength in the joint that comes from a tightly fitted shoulder. Better to chisel out the ramp.

Routing Dados

The router's often touted as the most versatile tool in the shop, and it certainly is useful for dadoing. The cutters offer convenient

An accurate, shop-made cutoff box is the best guide accessory to use for dadoing on the table saw. Set the cutoff box on the sled base, tight against the fence.The work won't shimmy or shift out of position as you slide the box across the dado cutter.

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