DeWalt DCS391N 18V XR 165mm Circular Saw (Body Only)

In-Depth Look

The DCS391N is part of the DeWalt 18V XR range. It uses a brushed motor rather than the brushless technology found in the newer DCS572.

Cutting Capacity

The 165mm blade delivers 55mm depth at 90 degrees, with a reduced depth at 45 degrees, handling 2x4 framing timber, 18mm sheet materials, decking boards, and most panel cutting tasks without difficulty. The bevel adjustment covers compound mitre cuts on skirting, architrave, and flooring work. For cutting full sheets of 8x4 ply or OSB, a straight edge guide or ripping fence improves accuracy and prevents the saw from wandering.

Electronic Brake and Safety

The electronic motor brake stops the blade within seconds of releasing the trigger, a significant safety advantage over saws that coast to a stop. When making repeated cuts in framing or sheet materials, this reduces waiting time and keeps fingers safer around the work area.

Brushed vs Brushless Consideration

Brushed motors are generally less efficient than brushless equivalents, so runtime per charge may be lower. For general site cutting rather than continuous heavy production work, this is unlikely to be a practical limitation. Check the DeWalt data sheet for the exact bevel range and cutting depths.

Battery Platform

As part of the DeWalt 18V XR platform, the DCS391N takes any standard 18V XR slide battery. Trades already running DeWalt drills, impact drivers, and lights can add this saw without buying a new battery ecosystem.

Verdict

A cordless circular saw for tradespeople already on the DeWalt 18V XR battery platform who do not need a brushless motor.

How It Compares

The DeWalt DCS391N is a cordless circular saw with a 165mm blade and a maximum cutting depth of 55mm at 90 degrees. It is supplied as a bare unit, so the battery and charger are bought separately, and it runs on the DeWalt 18V XR slide battery platform. It has a brushed motor with replaceable brushes, a cast magnesium base, an electronic motor brake, keyless bevel and depth adjustment, a spindle lock and a dust port.

That feature list suits it to site carpentry, cutting floorboards, stud work and sheet material for jobs where a cable would get in the way. Here is how it sits against the other types of saw you might consider.

The manufacturer does not list guide rail compatibility for this saw, so if rail work matters to you, a track saw is the more suitable tool. Adapters from other makers exist, but they are not on the official DeWalt list.

If you already own DeWalt 18V XR batteries, a bare unit adds a saw to the same platform. If you are starting from scratch, compare the whole platform, not only the saw.

Common Questions

What is the difference between a brushed and brushless circular saw in practice? A brushed motor uses carbon brushes that press against the motor, and these wear over time and can be replaced, as on this saw. A brushless motor uses electronics instead, so there are no brushes to wear. In everyday use both cut timber well. Check the data sheet for the exact model if motor type matters to you.

Which blade should I use for timber, sheet material and laminate? Fewer, larger teeth cut quickly through timber but leave a rougher edge. More, finer teeth leave a cleaner edge in sheet material and laminate, with slower cutting. Always match the blade diameter, bore and maximum speed to the saw, and choose a blade made for the material you are cutting.

How do I cut a straight line in a full sheet? Clamp a straight edge to the sheet and run the saw base along it, allowing for the gap between the blade and the edge of the base. Support the sheet so the offcut cannot drop and pinch the blade, for example on battens or sacrificial foam board, and set the depth so the blade just clears the underside.

What does the electronic brake do, and can I put the saw down straight after a cut? The brake stops the blade quickly after you release the trigger, which reduces the time it spins freely. Even so, wait until the blade has fully stopped before putting the saw down, and follow the instructions in the manual. Always unplug or remove the battery before changing a blade.