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For decades, cutting a 2×4 meant dragging out a 50-foot extension cord. Then the DeWalt DCS391 showed up.
This saw is legendary not because it is the most powerful (it isn’t), but because it was likely the first cordless saw most people ever owned. It is the backbone of the standard DeWalt 20V Combo Kits.
But in 2025, with high-powered “FlexVolt” and “XR” saws on the market, is this old-school brushed model still worth buying?
The “One Thing” (The Hook)
The “Blade-Left” Design. If you are right-handed (like 90% of the population), this saw is a dream. Most corded saws have the blade on the right, meaning the motor blocks your view of the cut line. The DCS391 puts the blade on the left.
- The Benefit: You have a perfect line of sight to exactly where the blade hits the wood. You don’t have to lean over the tool to see your mark. It makes following a pencil line incredibly easy for beginners.
The Good
- Magnesium Shoe: Cheap saws use stamped steel bases (“shoes”) that bend if you drop them. Once the shoe bends, you never cut square again. The DCS391 uses a cast Magnesium Shoe. It is thick, flat, and highly durable.
- Weight: At roughly 7 lbs, it is significantly lighter than a standard corded worm-drive saw. You can carry it up a ladder or use it overhead without straining your shoulder.
- The Speed: It spins at 5,150 RPM. While it lacks torque compared to the bigger saws, the high speed gives it a surprisingly clean cut on plywood and trim.
The Bad (The #1 Complaint)
It eats batteries (Brushed Motor). This is an older design with a Brushed Motor. As we discussed in our Decoder Series, brushed motors are less efficient.
- The Reality: If you try to rip a long sheet of 3/4″ plywood, this saw will drain a standard 2.0Ah battery in minutes. It gets hot and hungry. You must use at least a 4.0Ah or 5.0Ah battery to get any real work done.
Note: It is also a 6-1/2 inch saw, not a full size 7-1/4 inch. It cannot cut through a 4×4 post in a single pass (you have to flip the post).
The Verdict
Who is this for?
- Buy it if: You are a DIYer or Remodeler. If you primarily cut 2x4s, 2x6s, and plywood for weekend projects, this saw is cheap, accurate, and reliable. The blade-left visibility is unmatched for accuracy.
- Skip it if: You are a Professional Framer. If you rip wet pressure-treated lumber all day, this saw will stall. Buy the DeWalt DCS570 (Brushless) or the FlexVolt DCS577 instead.
Specs at a Glance
| Feature | DeWalt DCS391 |
| Blade Size | 6-1/2 Inches |
| Motor | Brushed |
| RPM | 5,150 |
| Bevel Capacity | 0-50 Degrees |
| Shoe Material | Magnesium |
| Warranty | 3 Years |
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