Dewalt 20V Atomic DCF850 Impact Driver Review

Dewalt DCF850 Angle 5

Quick take

The Dewalt 20V Atomic DCF850 fills the promise of the Atomic lineup with a highly compact design that squeezes well into tight spaces. It’s best suited for use on the job site or for the home prosumer that appreciates a quality, powerful tool. It capably drives big screws and lag bolts and offers good versatility with three drive modes. However, the battery run time is a letdown, and other flagship models beat its driving speed, all while retaining a compact footprint and lighter weight. This brute-force impact driver lacks precision for lighter-duty tasks, though the lower-speed drive modes do help recess screws somewhat accurately.

Brand Dewalt
Platform 20V Atomic
Motor Brushless
Tested torque in-lbs 659.4
IPM 3,800.0
Drive modes 3
Collet 1/4-inch hex
Same as DCF850B

Global rankings

21 models tested

TestResultRank
Driving speed (sec.)15.29
Torque (in-lbs)659.49
Battery run time (min.)30.015
RPM3,386.03
Bare weight (lbs)2.0812
Impacting noise (dBA)98.916

Editorial opinion

Methodology used: Heavy duty

Editorial rating

4.17 / 5 stars

Pros

  • Exceptionally compact collet-to-back length
  • Brushless motor
  • Drive modes
  • Long tool and battery warranty
  • One-handed bit changes

Cons

  • Battery run time
  • Lighter-duty impact drivers finish screws more consistently and accurately

Recommended configuration

DCF850P2

Includes (2) Max XR 20V 5Ah battery

Series lineup

Model #PlatformDrive ModesTorqueIPMReview
DCF84520V Max XR3612.6 in-lbs4,200.0Full review
DCF85020V Atomic3659.4 in-lbs3,800.0Full review
DCF88720V Max XR3880.2 in-lbs3,600.0Full review

Lab results

Torque

Dewalt DCF850 Torquemeter
Dewalt DCF850 Torque Charts

Max torque drive mode 1 (in-lbs): 659.4
Max torque drive mode 2 (in-lbs): 613.8
Max torque drive mode 3 (in-lbs): N/A
Max torque drive mode 4 (in-lbs): N/A

The DCF850 impresses with the torque output for its compact size, two features not commonly mentioned in the same sentence. It has sufficient torque to easily tackle most tasks around the job site and any demanding tasks for DIY projects at home.

Interestingly, the Dewalt 20V Max XR DCF845 has less torque in a larger footprint, highlighting the DCF850’s outstanding performance in its class.

Within the Dewalt lineup, the Dewalt 20V Max XR DCF887 has the most torque output of the models we’ve tested.

Compare torque test results

RPM

Dewalt DCF850 RPM Charts

Max RPM drive mode 1 (fwd.): 3,386.0
Max RPM drive mode 2 (fwd.): 2,705.0
Max RPM drive mode 3 (fwd.): 1,028.0
Max RPM drive mode 4 (fwd.): N/A
Max RPM drive mode 1 (rev.): 3,416.0
Max RPM drive mode 2 (rev.): 2,870.0
Max RPM drive mode 3 (rev.): 1,018.0
Max RPM drive mode 4 (rev.): N/A

The DCF850 impresses with its high RPM measurements in our tests. But RPM only tells one side of the story regarding driving performance, hence why the DCF850 didn’t shine as we expected in our driving speed tests.

The high RPM drives screws rapidly when not impacting. This impact driver ramps RPM quickly and achieves lofty readings, great for rapidly driving medium-length screws into soft materials without impacting.

But the high RPM can also lead to cam-out without the proper amount of downforce on the screw head.There are no consistent differences in RPM in forward or reverse.

Compare RPM test results

Driving speed

GRK total driving time forward (sec.): 15.2
GRK average driving time forward (sec.): 3.0
GRK total driving time reverse (sec.): 9.9
GRK average driving time reverse (sec.): 2.0

One sacrifice the DCF850 makes to achieve such a compact size is the driving speed for big screws and lag bolts. Let’s be clear: the DCF850 turned in solid results in our speed tests, powerfully driving long GRK screws without bogging down. This impact driver is competent for any heavy-duty task thrown its way around the home or on the job site.

But the bar is raised when competing with flagship models explicitly designed for brute force impacting. Check out the Milwaukee M18 Fuel 2953-20, Dewalt 20V Max XR DCF845, and Makita 18V LXT XDT19Z for faster driving speeds.

Compare driving speed test results

Drive modes

Dewalt DCF850 Drive Modes

Drive modes: 3
Drive mode 1:  High speed 
Drive mode 2:  Medium speed 
Drive mode 3:  Low speed/tightening 
Drive mode 4:  N/A 
Variable speed trigger: Yes

The DCF850 includes the essential drive modes that most users will find helpful. There’s a high and low speed impacting mode and a precision driving mode.

The high-speed mode is best for driving big structural screws, lag bolts, and longer common screws into dimensional lumber.The low-speed mode works well for driving screws flush into less dense materials, such as MDF, plastics, and drywall studs. This mode also works well finishing screws into dimensional lumber and other woods.

The precision mode works similarly well driving screws, but we found ourselves favoring drive mode 2 for precision driving tasks due to the extra power offered.

Users desiring more driving versatility should look to a Makita impact driver. The Makita 18V LXT XDT19Z and Makita 40V XGT GDT01Z include similar drive modes as the DCF850 but layer in additional assist modes, including self-tapping and bolt-specific settings.

Collet

Dewalt DCF850 Collet

Collet size: 1/4-inch hex
Quick-change collet: Yes
Bit-eject collet: Yes
Easy-insert collet: Yes

The DCF850 is excellent for one-handed bit changes. The quick-change collet has an easy-insert feature that doesn’t require sliding the collet forward to accept a bit. A bit-eject feature also lightly ejects the bit when sliding the collet forward.

Dewalt’s collet design is better executed than other brands offering similar features. The easy-insert mechanism is smooth for simple operation, and the bit-eject feature doesn’t jettison the bit too hard to potentially miss catching the bit.

Motor

Motor: Brushless
Impacts per minute: 3,800.0

Brushless motors offer significant performance improvements over brushed motors. The brushless motor in the DCF850 improves longevity, driving performance, and increases battery run time.

The advertised 3800.0 impacts per minute are surprisingly low for an impact driver with this much torque, partly explaining why it lags slightly behind flagship models from other brands in our driving speed tests.

Battery run time

Power type: Cordless
Battery run time (min.): 30.0
Battery tested: 20V Max 2Ah (DCB203)
Voltage: 20

One major letdown of the DCF850 is the performance in our battery run-time tests, barely reaching 30 minutes of no-load run time. The Dewalt 18V Max XR DCF845, Makita 18V LXT XDT14Z, or Makita 18V LXT XDT19Z are better options if you covet impressive battery and driving performance.

We tested battery run time with the 2Ah battery version. We expect the battery run time to similarly underperform when running the DCF850 with a 20V Max XR 5Ah battery and comparing it with other 5Ah setups, albeit battery run time will increase significantly.

Compare battery test results

Charging time

Dewalt 20V Fuel Gauge

Charger tested: Dewalt 20V Max (DCB115)
Charging time 2Ah battery (min.): 59.0
Charging time 2.5Ah battery (min.): Not tested
Charging time 4Ah battery (min.): Not tested
Charging time 5Ah battery (min.): 139.0
Charging time per Ah (min.): 28.7
Fuel gauge: On battery

One letdown is that the standard charger included in most Dewalt kits (model DCB115) charges batteries slowly compared to other manufacturers. In our testing, the DCB115 charged at a rate of 28.7 minutes per Ah. Several other brands charge at a rate of 20 minutes per Ah or lower.

However, this charger charges 12V and 20V Max platform batteries in one, conveniently saving shelf space in your shop if you have several tools in the Dewalt ecosystem.

Compare charging test results

Design & ergonomics

Stands upright w/o battery: Yes
Stands upright w/ battery: Yes
Grip material: Rubber overgrip
Magnetic holder: No
Bit holder: No
Belt hook: Yes
Handle angle (deg.): 83.0
Head angle (deg.): 92.0

Weight

Dewalt DCF850 On Scale

Bare weight (lbs): 2.08
Weight w/ 2Ah battery (lbs): 2.88
Weight w/ 2.5Ah battery (lbs):  Not tested
Weight w/ 4Ah battery (lbs):  Not tested
Weight w/ 5Ah battery (lbs): 3.48

The Dewalt DCF850 is compact, but its size doesn’t translate to low weight. The DCF850’s bare weight is moderately heavy. The Makita 18V LXT XDT19Z has similar driving performance and size at a lower weight.

The working weight can differ significantly depending on the battery run in your setup. To keep it as lightweight as possible, We recommend combining the DCF850 with Dewalt’s 20V Powerstack 1.7Ah battery, which weighs less, has a smaller footprint, and runs longer than Dewalt’s 20V Max 2Ah battery, which is a solid alternative for a svelte setup.

If weight is less of a concern, pair the DCF850 with Dewalt’s 20V Max XR 5Ah battery for a longer run time and improved driving performance. Interestingly, this impact driver is lightweight with the 20V Max XR 5Ah battery compared to other 5Ah battery and tool setups.

Compare weight test results

Footprint

Dewalt DCF850 Footprint1
Dewalt DCF850 Footprint2

Max height (bare tool, in.): 8.125
Max width (bare tool, in.): 3.000
Collet to back length (in.): 3.875
Base length (bare tool, in.): 3.625
Base width (bare tool, in.): 3.000
Trigger circumference (in.): 6.750
Handle circumference (in.): 5.125

The DCF850’s footprint is best described as compact for a heavy-duty impact driver. Notably, the collet-to-back length is incredibly short. However, the max height and max width add bulk, limiting its ability to squeeze into some tight corners with little clearance height or width.

Compare footprint test results

Driving clearance

Min. interior width clearance (in.): 7.250
Min. top edge clearance (in.): 1.250
Min. interior 45-deg. clearance (in.): 5.500

The DCF850 performed exceptionally well in our interior width and 45-degree clearance tests thanks to its stubby collet to back length. Few models break the 6-inch threshold in our 45-degree test, which the DCF850 handily beat. This combined performance makes it an excellent fit for squeezing into tight spaces and corners.

Compare driving clearance test results

Noise

DCF850 Impact Driver Noise Chart

Max noise no load (dBA): 85.2
Max impacting noise (dBA): 98.9

The DCF850 is designed for heavy-duty tasks, and its impact noise reflects this approach. It’s one of the louder impact drivers we’ve tested. The Milwaukee M18 Fuel 2953-20 shaves off a few decibels when impacting, should you be looking for a similarly powered and compact option.

Jumping down in torque, the Milwaukee M12 Fuel Surge 2551-20 and Milwaukee M18 Fuel Surge 2760-20 are other options to consider. Both are hydraulic impact drivers with far more subtle impacts.

Compare noise test results

Vibration

Max head vibration no load (m/s2): 54.0
Max grip vibration no load (m/s2): 3.5

Compare vibration test results

Light

Dewalt DCF850 Light
Dewalt DCF850 Light Closeup

Light: Yes
Light on/off: No
Number of lights: 3
Light time delay (sec.): 20.0

The DCF850’s work light illuminates a small surface area but is focused in the right location and is bright. One minor gripe is the light’s time delay, which doubles the time for most impact drivers, unnecessarily draining battery life.

There is no dedicated flashlight mode, one featured included with some Makita impact drivers, where the trigger acts as an on/off button to turn on the light without moving the motor. You also can’t disable the light.

Warranty

Tool warranty (years): 3
Battery warranty (years): 3

Dewalt stands behind the durability of its impact drivers with exceptionally-long warranties. The DCF850 has a three-year warranty. Dewalt 20V Max XR batteries include a two-year warranty.

Dewalt also offers free maintenance and replacement of worn parts for one year for the DCF850 and three years for its 20V Max XR batteries.

Nathan Hamilton
Nathan Hamilton
Nathan Hamilton is the founder of DIY Gear Reviews and a recognized expert in the home and DIY space. He has over 200 bylines covering topics such as power tools, hand tools, and woodworking. Nathan is the strategic director for DIY Gear Reviews, deciding everything from the content covered to designing the testing methodologies for lab-tested reviews. He can be emailed at nhamilton@diygearreviews.com.

Related

Leave a Comment