DEWALT DCS391B: problems, parts and running costs
Checked: 2026-10-12
Summary
The DCS391B is a lightweight brushed-motor 20V MAX cordless circular saw sold as a bare tool, so batteries and a charger are extra. The main complaints are slow ripping, a brushed motor that drains batteries faster than brushless saws, and missing features such as positive bevel stops, an LED light and a dust port. It is a good buy under $99 for someone who already owns 20V MAX batteries and cuts occasionally.
Common problems and fixes
- Brushed motor is less battery-efficient — it draws more than the brushless DCS565B and DCS570B, and owners on r/Dewalt call the DCS391 outdated for that reason; there is no fix short of buying a brushless saw. [7]
- No positive bevel stops — the bevel has no stops at 22.5° or 45°, and the scale is engraved with no contrast fill, so it is hard to read; set the angle against a square. [1]
- No LED light, no dust port, no rafter hook — the saw has none of these; add an external light or a vacuum where needed. [1]
- Depth adjustment indicators are awkwardly placed — owners report setting depth by eye against the blade instead of the markings. [1]
- Not for daily or professional use — TechGearLab recommends it for casual and weekend DIY use only. [1]
Parts and consumables
- 6-1/2 in carbide-tipped blade — included with the saw; it uses a 5/8 in arbor, so standard 6-1/2 in blades fit. [1][4]
- On-board Allen wrench — included for blade changes using the spindle lock. [1]
- 20V MAX battery and charger — sold separately; the saw runs on any DEWALT 20V MAX battery. [4]
Yearly running cost
Not enough data. Battery life in real-world use (cuts per charge) was not independently measured, so no yearly figure can be computed. Blades and any extra batteries are the main costs.
When it is a good buy
At $99 or less the DCS391B is strong value for occasional use by someone who already owns 20V MAX batteries. Between $100 and $139 it is fair value, and the brushless DCS565B is the better choice because it is more battery-efficient. Above $159 the DCS570B, with a 7-1/4 in blade, brushless motor and positive stops, is the better saw. TechGearLab listed the saw at $159 in February 2026, Empire Rigging listed it at $159.00, and Global Industrial listed it at $165.95.