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crwdns2935311:0crwdnd2935311:0crwdne2935311:0 crwdns2935313:0Dewalt Impact driver DCF840crwdnd2935313:0crwdnd2935313:0crwdne2935313:0

  1. Dewalt Impact driver DCF840 Teardown, Complete tool and battery: crwdns2935265:01crwdnd2935265:01crwdnd2935265:02crwdne2935265:0 Dewalt Impact driver DCF840 Teardown, Complete tool and battery: crwdns2935265:01crwdnd2935265:02crwdnd2935265:02crwdne2935265:0
    • This guide covers the complete tool and battery.

  2. Dewalt Impact driver DCF840 Teardown, Opening the tool: crwdns2935265:02crwdnd2935265:01crwdnd2935265:01crwdne2935265:0
    • Remove the 8 screws holding the two halves together.

  3. Dewalt Impact driver DCF840 Teardown, Internal mechanism: crwdns2935265:03crwdnd2935265:01crwdnd2935265:02crwdne2935265:0 Dewalt Impact driver DCF840 Teardown, Internal mechanism: crwdns2935265:03crwdnd2935265:02crwdnd2935265:02crwdne2935265:0
    • Battery Contacts

    • Potted Circuit

    • Brushless Motor

    • Impact Gearbox

  4. Dewalt Impact driver DCF840 Teardown, Gearbox removed: crwdns2935265:04crwdnd2935265:01crwdnd2935265:01crwdne2935265:0
    • With the Gearbox removed we are left with the motor on one side and the light ring on the other.

  5. Dewalt Impact driver DCF840 Teardown, Trigger mechanism: crwdns2935265:05crwdnd2935265:01crwdnd2935265:03crwdne2935265:0 Dewalt Impact driver DCF840 Teardown, Trigger mechanism: crwdns2935265:05crwdnd2935265:02crwdnd2935265:03crwdne2935265:0 Dewalt Impact driver DCF840 Teardown, Trigger mechanism: crwdns2935265:05crwdnd2935265:03crwdnd2935265:03crwdne2935265:0
    • Neutral: Trigger Locked

    • Forward

    • Reverse

    • When selector is neutral this tab keeps the trigger from being depressed

  6. Dewalt Impact driver DCF840 Teardown, Splitting the gearbox/impact section: crwdns2935265:06crwdnd2935265:01crwdnd2935265:01crwdne2935265:0
    • Gear box fits into housing as a press fit with two clips. Releasing the two clips allows the gear box to be freed from its housing.

  7. Dewalt Impact driver DCF840 Teardown, Gearbox / Impact section: crwdns2935265:07crwdnd2935265:01crwdnd2935265:03crwdne2935265:0 Dewalt Impact driver DCF840 Teardown, Gearbox / Impact section: crwdns2935265:07crwdnd2935265:02crwdnd2935265:03crwdne2935265:0 Dewalt Impact driver DCF840 Teardown, Gearbox / Impact section: crwdns2935265:07crwdnd2935265:03crwdnd2935265:03crwdne2935265:0
    • Planetary gear set: reduce motor speed and increase torque

    • Splines to gear box case

    • Internal teeth for planetary gear set

    • Spring (hard to see) for impact function: base spins and strikes output drive labeled with blue arrow in last picture

  8. Dewalt Impact driver DCF840 Teardown, Battery: crwdns2935265:08crwdnd2935265:01crwdnd2935265:01crwdne2935265:0
    • 20V battery at full charge

    • Nominally around 18.5V

  9. Dewalt Impact driver DCF840 Teardown, Splitting battery case: crwdns2935265:09crwdnd2935265:01crwdnd2935265:01crwdne2935265:0
    • Remove four screws to open battery

    • Spring for latch to lock battery into tool

  10. Dewalt Impact driver DCF840 Teardown, Battery details: crwdns2935265:010crwdnd2935265:01crwdnd2935265:02crwdne2935265:0 Dewalt Impact driver DCF840 Teardown, Battery details: crwdns2935265:010crwdnd2935265:02crwdnd2935265:02crwdne2935265:0
    • 5 cells nominally 3.7V in series.

    • 0V (GND)

    • 12V (likely for LED light ring)

    • 3.7V (not connected to tool)

    • 18.5V

    • 18.5V (main output)

Wieli

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