What the tool is made for
DEWALT describes its DCF887 as designed for impact screwdriving, its impact function making it particularly useful for driving fasteners in wood, metal and concrete. Milwaukee's manual for the 2953 says the driver is intended for use with drill and driver bits. Both are 18 V tools with three speed modes; both hold accessories in a 1/4 in hex quick-release chuck rather than a jawed chuck.
| Feature | DEWALT DCF887 | Milwaukee 2953 |
|---|---|---|
| Chuck | 1/4 in hex, quick release | 1/4 in hex |
| Speed, by mode | 0–1000, 0–2800, 0–3250 rpm | 0–1700, 0–3000, 0–3900 rpm |
| Impacts per minute | 0–3800 | 0–1400, 0–3600, 0–4400 by mode |
| Torque stated | 205 Nm maximum | Not stated in the manual |
| Accessories | Impact accessories only; others may break | Drill and driver bits; only those recommended for the tool |
Each figure from the tool's own manual; Milwaukee gives speeds at no load and impacts under load. Not a ranking.
Bits in an impact driver
The chuck accepts 1/4 in hex shanks and nothing else, so a round-shank bit cannot go in at all. What does fit is a hex-shank bit, and here the two manuals part company. DEWALT says to use impact accessories only and to inspect each for cracks before use, because a non-impact accessory may break and create a hazard. Milwaukee says the 2953 is intended for drill and driver bits and to use only accessories specifically recommended for the tool. Follow the manual for the driver you own, and the bit maker's statement of what its bit is rated for; a hex shank alone does not make a bit impact-rated.
For holes that must be clean, square or flat-bottomed, the bits made for that work run in a drill or a drill press: the guide to wood drill bits sets out which tool each maker lists its bits for.
Driving screws with impacts
- Impacting tightens. Milwaukee: the longer a screw is impacted, the tighter it becomes; avoid excessive impacting, and take particular care with small fasteners, which need less.
- Learn by practice. Milwaukee suggests driving practice fasteners and noting how long each takes, and checking tightness with a hand torque wrench where it matters.
- Start slowly. DEWALT's variable trigger is for starting holes or fasteners; continuous use in the variable range can damage the switch.
- Prepare the hole. A pilot hole is sized for the screw and the wood, whatever drives the screw. Pilot and clearance sizes by gauge, for hardwood and softwood, are on the pilot hole chart.
Safety— Holding and changing bits
DEWALT: one hand on the main handle, held securely in anticipation of a sudden reaction; the direction button in its centre lock-off position, or the battery out, before changing an accessory. Milwaukee: wear eye protection.
Impact driver or drill/driver
| Job | Drill/driver | Impact driver |
|---|---|---|
| Drilling round-shank bits | Yes, within the chuck's 13 mm (DCD777) | Cannot hold them |
| Seating a screw to a set torque | Clutch collar, lowest setting that seats it | No clutch described; by feel and practice |
| Driving fasteners | Drilling and screwdriving, per DEWALT | Designed for impact screwdriving, per DEWALT |
| Hex-shank drill bits | Fit the jaws | Per each driver's manual on accessories |
From DEWALT's DCD777 and DCF887 manuals and Milwaukee's 2953 manual. How the drill/driver's clutch and gears work is in drills and drivers.
Before using an impact driver
- Bit has a 1/4 in hex shank
- Bit is one the driver's manual allows, and inspected for cracks
- Battery out or lock-off set while changing it
- Mode chosen, and a pilot hole drilled where the wood needs one
- Firm grip, ready for a sudden reaction
- Eye protection on
Sources
Every figure and instruction is DEWALT's for its DCF887 or DCD777, or Milwaukee's for its 2953; other drivers' manuals may say otherwise. Milwaukee's manual gives no torque figure, so the two drivers' torque is not compared. The primary keyword is editorial. No tool was tested.
- 1.
DCF887 Cordless Impact Driver instruction manual (English). DEWALT.
Used for: The DCF887: designed for impact screwdriving, useful for driving fasteners in wood, metal and concrete; 18 V; three modes at 0–1000, 0–2800 and 0–3250 rpm; 0–3800 impacts per minute; 205 Nm maximum torque; a 1/4 in hex quick-release chuck that accepts hex accessories only; impact accessories only, inspected for cracks, since non-impact accessories may break; the button in the lock-off position or the battery removed before changing accessories; one hand on the main handle, held securely against a sudden reaction; variable speed for starting holes or fasteners, not continuous use.
- 2.
M18 FUEL 1/4" Hex Impact Driver 2953-20 Operator's Manual (as hosted by a distributor). Milwaukee Tool.
Used for: The 2953-20: 18 V; 0–1700, 0–3000 and 0–3900 rpm and 0–1400, 0–3600 and 0–4400 impacts per minute by mode, plus a mode for self-tapping screws in sheet metal; intended for use with drill and driver bits; only accessories recommended for the tool; the longer a fastener is impacted, the tighter it becomes, smaller fasteners needing less; practice and checking with a hand torque wrench; eye protection.
- 3.
DCD777 Cordless Drill/Driver instruction manual (English). DEWALT.
Used for: A drill/driver with a 13 mm keyless chuck, a clutch collar for screwdriving and two gears, for comparison.
- 4.
Countersinks, Counterbores, Tapered Drills, Plug Cutters catalog (PDF dated 2006), page 4: Recommendations for Wood Screw Predrill Sizes and Lengths. W. L. Fuller, Inc., 2006.
Used for: Pilot, shank-clearance and countersink sizes by screw gauge.
About this guide
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