The DWS780: DeWalt's New 12-in. Slider | THISisCarpentry

As carpenters, we rely on our miter saws to help us do fast, accurate work. Our cut stations are the heart of our jobsite setups. It comes as no surprise that we expect a lot out of these tools—we are continually on the lookout for a saw that is precisely calibrated, feels natural, operates strong and smooth, offers large cutting capacity, and doesn’t weigh a ton. No single saw satisfies these criteria perfectly, and the new DWS780 is no exception. I had high hopes for this saw, some of which it met and some of which it didn’t.

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I never used to be much of a DeWalt fan, but their stuff seems to be getting better and better. A good number of my new and replacement tool purchases over the last year have been DeWalt. I had recently started a new position as a lead carpenter for a trim subcontractor when I first noticed this new DeWalt 12″ sliding saw, and I was intrigued to see how it performed against the competition.

First, the light: DeWalt’s XPS Crosscut Positioning System utilizes bright LEDs that are projected on both sides of the blade. This illuminates the work-piece while simultaneously creating a shadow line you can cut to. It’s brilliant. Every saw should have one.

The kerf ends up slightly wider than the shadow line, but it really helps you index to your mark quickly, especially when making bevel cuts where it is more difficult to visualize where the blade will enter the work-piece.

The saw is impressively lightweight (56 pounds) and a well-placed handle makes it easier to carry. It offers very good cutting capacity: 60-degree miters to the right, 50-degree miters to the left, and 13 7/8-in. (advertised) square cuts.

The miter scale is chrome with crisp, etched black angle markings. There is no vernier or micro-adjust knob, but the angle gradations are a full 1/8 in. apart so it is pretty easy to set the saw to cut at 1/2 a degree.

The detents feel reassuringly solid, and the detent override located to the side of the miter lock knob allows you an unhindered angle adjustment when you need it.

If you depress the button behind the miter lock knob with your thumb while swinging the saw from side to side, you can glide over the detents, preventing them from wearing out prematurely.

The saw was square out of the box, so no adjustment was necessary. I removed the miter scale anyway to see how difficult it would be to calibrate again. If your saw isn’t cutting square, the recalibration process would begin with loosening the four star screws while holding the miter scale in place, using the onboard star driver/wrench. You don’t need to take them all the way out, but if you do, note that the two near the front are shorter. From the factory, these screws are pretty tight; it helps to stick a nut driver in the onboard wrench to give you some extra leverage. After you get the miter scale loosened so it rotates freely, lock the saw into the 0* detent and nudge it back and forth until it is square, checking both fences as insurance. I like to use a digital bevel square for this. Once you’re satisfied, tighten the screws back up and re-check to make sure the position didn’t change. Overall I think this design makes adjustment easier and more accurate than the Makita, where you have to move the fence to correct for square.

The bevel scale is yellow with etched black angle markings. It measures over 5 inches across, but due to the design of the pointer it is difficult to set it finer than 1 degree. The bevel calibration screw is located in front and to the left of the bevel scale. Turning it adjusts the default position of the saw at 0 degrees (90 degrees to the saw table).

The saw required some minor adjustment out of the box, and I have adjusted it several times since, which does make me suspicious about the long-term reliability of the bevel calibration. (Read David Collins’ “Miter Saw Tune-Up” article for more information on miter saw adjustments.)

Changing the bevel-cutting angle requires reaching around the back of the saw to the three-pronged 4-in. cast knob. It’s not the most comfortable arrangement, but I tend to prefer it to the single plastic lever on my Makita.

After I received the saw I immediately changed the blade out for a Freud 80T since I prefer to use Freud blades instead of stock blades. Changing the blade is simple: unplug the saw, loosen a bolt (using the onboard star driver/wrench) in order to slide back the blade cover and fix the guard in the raised position. Next, engage the spindle lock and unscrew the arbor nut, again using the onboard wrench. Reverse the process after installing the new blade. (A rule of thumb I like to remember for blade changes: loosen with the blade rotation, tighten against the blade rotation.)

Out of the box, I noticed the slide action was quite rough. I added some lubricating oil and tinkered with the slide adjustment screw, but my tinkering was to no avail. This is a bummer, especially on bevel cuts where there is added torque on the slide rails while cutting. I suppose the smaller-than-normal rails could have something to do with it, but it just feels like sloppy machining between the rails and the guides.

The other major detriment to this saw is the huge amount of flex in the saw head at full extension—almost a full 1/8 in. in either direction from center. You can’t cut trim accurately when the saw head is flexing all over the place, especially when you’re shaving 1/32 in. off the end of a work-piece. The blade gets “pushed” right off the edge of the board, and makes this common and simple task frustratingly difficult.

I put the saw through its paces cutting poplar trim, AZEK, 2x pine, ash tongue and groove, and oak paneling. Cutting cupped 1×8 oak baseboard on a bevel, the saw visibly struggled, mostly due to the issues mentioned before—rough slide operation and excessive flex in the saw head. As a result, I tried to avoid using this saw for wide, demanding cuts. The 10-inch Makitas and Hitachis that I use track much more reliably.

Dust collection is a challenge on any miter saw, but hooking up a vacuum to this saw does make a worthwhile difference, which is more than can be said for some other saws. I wondered if the light would trigger the auto-start on our Festool vacuums, but it didn’t—the vacuum only came on when the saw motor was switched on.

The base of the saw has a low profile—it sits close to the table when mounted, which aids in keeping the cut station clean by preventing chips and sawdust from building up underneath.

This saw does come with a built-in dust shroud, which can also be helpful.

Overall, here’s where I’ve landed: This saw excels if you need to be highly mobile and handle a wide variety of small- and medium-sized jobs. That said, it wouldn’t be my first choice to set up on a technical and demanding trim-out—it’s just not precise enough throughout the slide range, which is really unfortunate, as there are a lot of other things about the DWS780 that are really compelling.

Pros: Great light; easy-to-read miter and bevel scales; not terribly loud; good capacity/weight ratio.  

Cons: Rough slide action; excessive flex in saw head; no soft start; feels slightly underpowered.  

Price: $530-$675, depending on retailer.