Milwaukee M12 SUBCOMPACT Brushless 3/8 in. Drill/Driver (Bare Tool)

Milwaukee M12 SUBCOMPACT Brushless 3/8 in. Drill/Driver (Bare Tool)

By Milwaukee · Cordless Drills · Power Tools

  • Subcompact brushless: 350 in-lbs torque, 0-1,650 RPM
  • 3/8 in. single-sleeve ratcheting chuck
  • Only 6.4 in. long, 2.0 lbs bare (2.8 with CP2.0)
  • 12-speed trigger control
  • M12 REDLITHIUM battery compatible (sold separately)

Lowest price seen
$129.00
from $129.00 at MaxTool · Checked Oct 8, 2026

Prices are snapshots. Check the current price with the store.

Summary

A lightweight, brushless M12 drill/driver for light and medium-duty work in cabinets, tight access and overhead jobs. It is the tool-only 3401-20, so budget for a battery and charger unless you already own M12 gear.

Strengths

  • At about 1.9 lb with a compact pack, it is light and balanced for overhead and tight-cupboard work.
  • A reviewer drilled a 2-inch hole saw through a pine 2x4 in about a minute.
  • The 12+1 clutch is precise for cabinet hardware and small screws.
  • Any appropriate M12 battery works, so existing owners need no new charger.
  • The brushless motor has no carbon brushes to replace on a schedule.
  • A five-year limited tool warranty outlasts many competing cordless drill warranties.

Weaknesses

  • The 3/8-inch chuck will not take a straight 1/2-inch shank.
  • There is no hammer mode, so masonry means switching tools.
  • The in-handle battery grip is chunky and may not suit small hands.
  • The tool-only 3401-20 ships without a battery or charger.
  • An intermittent no-start case was reported after only two uses.
  • The factory chuck is held with thread-locking compound, making modification hard.

Verified specifications

IdentityMilwaukee 3401-20, M12 Subcompact Brushless 3/8-inch Drill/Driver, 12 V DC; tool-only, no battery or charger.
Motor and gearboxbrushless, 350 in-lb claimed peak torque; two speeds, 0–450 RPM low and 0–1,550 RPM high.
Chuck and clutchmetal 3/8-inch keyless ratcheting chuck; mechanical collar with 12+1 positions.
Capacitiessteel twist bit to 1/2 inch with a reduced shank, 1-1/4-inch flat/spade wood bit, 1-inch auger, 2-inch hole saw, 1/2-inch maximum screw diameter.
Size and mass5.4 inches long and 2 lb with a kitted battery (maker); measured about 1.6 lb bare and 1.9 lb with a CP2.0 pack.
Featurestwo-speed selector, LED work light, fuel gauge, rubberized grip, belt clip, and direction switch with a middle trigger lock.
ProtectionREDLINK circuitry monitors current, voltage and temperature; recommended ambient operating range 0–125°F.
ManualPN-00-02389.
Service referenceparts bulletin PN0002390 (October 2024), serial family R07A.
Full research notes and sources

What it is and which model

The 3401-20 is the smallest practical M12 drill: a brushless 3/8-inch drill/driver rated 12 V. It is not M12 FUEL and not a hammer drill, so do not confuse it with the FUEL 3403-20 1/2-inch drill/driver or the 3404-20 hammer drill. Milwaukee’s own 3401-20 page carries a generic kit paragraph, but 3401-20 is tool-only and the kit is 3401-22. The drill takes slide-in M12 batteries and works with the maker’s current M12 system.

Clutch, gearing and capacity

Two mechanical gears give 0–450 RPM and 0–1,550 RPM. The keyless metal chuck is 3/8 inch, which is shank capacity rather than a hole-size limit: Milwaukee lists drilling up to 1/2 inch in steel with a reduced shank, 2-inch hole saws, 1-inch augers and 1-1/4-inch spade bits, and screws to 1/2 inch. The 12+1 clutch is mechanical and approximate, so test it on scrap before driving delicate screws. A ratcheting sound when the chuck opens or closes is normal, and a bit must sit centered in all three jaws.

Problems owners report

There is no published failure rate for this model, and it only reached buyers in 2025, so treat the reports below as individual cases. In February 2026 an r/MilwaukeeTool owner identified a 3401-20 bought about six weeks earlier that would only run intermittently after two uses, despite testing three different batteries that worked on other M12 tools; the cause and outcome were not posted. In the same thread another owner reported nine months of daily trouble-free use. Separate owners attempting an unofficial chuck-to-hex conversion found the factory chuck held by thread-locking compound, and a Milwaukee service center declined the custom work. General M12 battery-contact trouble is possible: if output drops, make sure the pack is fully engaged and clean and dry the contacts before returning the tool.

Parts and running costs

There is no subscription, filter or required paid app, so mandatory annual spend is zero apart from bits, electricity and repairs. A belt-clip kit, Milwaukee 42-70-0497, is $6.14 at Biedler’s and $6.25 at Great Lakes Power Tools. A housing connection clip, 42-70-0058, is $1.15 at Biedler’s and $5.95 at Home Depot Repair Parts. An optional side bit holder, 49-16-3697, is $14.99 at Home Depot; it does not turn the keyless chuck into a permanent hex chuck. A compatible CP2.0 battery, 48-11-2420, is $69 at Home Depot with two years of coverage, and the M12 charger 48-59-2401 was $22.40 at Home Depot, marked down from $64. Battery recharge is the only running energy cost: a CP2.0 pack stores about 24 Wh, and even 100 full cycles is only about 2.4 kWh of stored energy, with wall use higher. No separately priced OEM chuck, motor, control-board or gearbox parts appear in the public service sheet.

Prices and which version to buy

In October 2026 the 3401-20 was $129 at Home Depot, Acme Tools and Tool Nut, though Tool Nut showed it out of stock with a 14–20 day order time. Expired June 2026 Slickdeals offers hit $69 at Home Depot, with May offers at $79 and $89. The 3401-22 kit, with the same drill plus two CP2.0 batteries, a charger and a bag, was $149 at Home Depot, only $20 more than the bare tool. For a first M12 purchase that kit makes more sense; someone who already owns M12 batteries and wants more power should look at the M12 FUEL 3403-20 at $149 or the 3404-20 hammer drill at $159.

Sources

Manufacturer:

Independent reviews:

Owner reports:

Parts and stores:

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