DeWalt FlexVolt DCS781 12in Cordless Miter Saw Review: Dust Collection Done Right

Introduction

Cordless miter saws have always asked for a compromise: dual batteries for power, weak dust collection, and a saw that weighs a ton. The DeWalt FlexVolt DCS781 12in cordless sliding compound miter saw makes a different bet. It runs on a single battery, packs regenerative braking to squeeze more cuts per charge, and claims to capture 90% of the dust it creates. After cutting through hundreds of pieces of trim, dimensional lumber, and hardwood, that claim holds up better than most marketing numbers do.

Key Features That Stand Out

The DCS781 is loaded with thoughtful controls. The slide lock moves from the transport position into a forward chop position, which lets you cut upwards of 6 1/2 inches of base in a vertical position. Right next to it, the head lock moves the head up and down or automatically locks it in place when pushed down.

There is also an adjustable depth stop controlled by a wing nut and lever, and it flips out of the way entirely when you don’t need it. The saw miters 50 degrees left and 60 degrees right, with detents at 0, 15, 22.5, 31.6, and 45 degrees, plus a 60-degree detent to the right. It bevels 46 degrees in both directions, with bevel paw detents at 22.5 and 33.9 degrees along the way, and the bevel return lock brings it back to zero quickly.

Other nice touches include adjustable and removable upper fences on both sides for extreme bevel cuts, a secondary lever that locks the slide in any position, and an LED light on the dandle for shadow-line visibility that also turns on with the trigger. The saw spins at 3,800 RPM and ships with a DeWalt fine cut 60-tooth blade. Total weight is 51 pounds, with a horizontal cutting capacity of 12 3/16 inches and 6 1/2 inches of vertical trim capacity.

Dust Collection: The Headline Act

Dust collection is where this saw separates itself. You can use the included bag, the DeWalt locking mechanism for a flexible vacuum, or a slide-over adapter for standard vacuum connections. Connected to a DeWalt Stealth Sonic style vacuum, a 45-degree cut produced almost nothing escaping the system. Even underneath the saw and inside the vacuum, dust ends up where it should.

Over more than 300 cuts in one session, very little dust accumulated on the saw, on the operator, or around the work area. One technique tip: making a full-depth cut with the rubber deflector bent up lets a little dust escape around the top. Coming forward only as far as needed and making the cut smartly sends nearly everything straight up into the chute. Cutting taller stock like 2x10s or cutting baseboard standing upright produces slightly more escaping dust, but it remains minimal. This is a saw you could genuinely use inside a finished home for trim carpentry without spreading dust through the whole house.

Runtime and Battery Performance

DeWalt claims upwards of 600 cuts in trim and 255 cuts in 4x4 lumber on a charge. In testing, after 92 cuts into a 4x4 chopped into small pieces, the 9Ah FlexVolt battery still showed two bars. At 192 cuts it dropped to one bar, then briefly popped back up to two while idle.

The test continued into a 2x10, where 68 additional cuts were made while the battery held steady at one bar and stayed warm but not hot, roughly in the 85 to 90 degree range. The saw itself barely heated up, peaking around 89.6 degrees even with back-to-back continuous cutting. Since this works with 9Ah, 12Ah, and 15Ah FlexVolt batteries, heat and runtime should not be a concern for most users.

The regenerative braking system uses the motor as a generator while the blade slows down, putting energy back into the battery, similar to electric vehicle technology. How many cuts it actually recovers is hard to quantify, but the mechanism works and contributes to the impressive overall runtime.

Cutting Performance and Accuracy

The saw is incredibly smooth, and cut quality on oak was excellent with only a slight tear-out on the back face. The 60-tooth fine cut blade leaves clean, accurate cuts, and the detent system is precise and easy to use. One small improvement worth making: adding tape to create a zero-clearance insert helps stop small offcuts dropping through the throat plate.

Power held strong even as battery voltage dropped partway through the session, which matters since nobody works exclusively on a freshly charged pack. For trim work, the claimed 600 cuts per charge is entirely believable. Heavier stock like 4x4s and 2x10s puts more stress on the saw, but it never faltered during testing.

Buying Advice

At $699 bare and $850 for the kit that includes a 9Ah FlexVolt battery and 6-amp charger, the DCS781 is not cheap. But the kit is not skimping on the extras: you get a good battery, a good charger, and a good blade in the box. Anyone moving from the older dual-battery FlexVolt saw will find this single-battery design makes the previous generation look dated in nearly every way.

Conclusion

This is the best miter saw we have tested to date. The dust collection is genuinely phenomenal, the runtime on a single 9Ah battery is spectacular, and the overall refinement of the cutting experience is spot on. For trim carpenters and contractors who work indoors and care about clean jobsites, the DCS781 is worth every bit of its asking price.