Drilling a hole
Fit the bit with the battery out
Remove the battery, open the chuck, insert the shank about 3/4 in and tighten the sleeve by hand while holding the tool. Never tighten a bit by gripping the front of the chuck and running the motor; check the bit is secure before starting, since a loose one can be thrown out.
Set the collar and gear
Turn the collar to the drill symbol: the clutch works only when driving screws. Choose the gear for the job with the drill stopped — gear 1 for torque, gear 2 for speed — and never shift while it runs.
Clamp the work
Clamp it to the bench, with scrap under any through hole in thin stock. Holding the work by hand or against your body is unstable, DEWALT warns.
Take a two-handed grip
Use the side handle if the drill has one; if not, one hand on the handle and one on the battery pack, so you can control the twist.
Start and push straight
Start slowly on the mark, then keep the pressure in a straight line with the bit — enough to keep it biting, not enough to stall the motor or bend the bit off line. Avoid running for long in the part-squeezed trigger range.
Ease through the exit
Reduce pressure for the last part of the hole so the bit eases through instead of breaking out.
Withdraw running
Keep the motor running as you pull the bit back out; it helps prevent jamming.
Safety— If the drill stalls
An overloaded drill stalls with a sudden twist, so expect it and grip firmly. If it stalls, release the trigger at once, take the bit out of the work and find the cause — overload or the wrong use. Do not pull the trigger on and off to restart a stalled drill; DEWALT says that can damage it.
Pilot holes and driving the screw
Joining two boards with a screw takes two holes: a clearance hole through the top board, so the shank passes freely, and a pilot hole in the bottom board, so the threads bite without splitting it. The Wood Handbook's rule is a lead hole about the shank's diameter for the shank, and for the threads, close to the root diameter in dense woods and smaller in proportion in light ones. W. L. Fuller gives sizes for each gauge, for hardwood and softwood, on the pilot hole chart.
Drill the pilot
With the collar on the drill symbol, drill the pilot to the screw's length in the bottom board.
Drill the clearance hole
Change to the clearance bit and drill through the top board only. Countersink or counterbore if the head is to sit flush or below the surface.
Switch to driving
Fit the driver bit, turn the collar to a low number, and run a practice screw in scrap. Raise the setting only until the screw seats at the depth you want: DEWALT says to use the lowest setting that does.
Drive, don't hammer
Turn screws in. The Wood Handbook says never to start or drive one with a hammer, which tears the wood fibres and damages the threads.
Choosing the screw
Screw length is a separate choice from gauge. Fuller's rule of thumb is about a third of the screw's length in the piece being attached and two-thirds in the piece it is attached to. Screw sizes by gauge are on the wood screw size chart. For clean rims, flat-bottomed holes and large holes, see drilling clean holes; for which bit to fit, the guide to wood drill bits.
Before pulling the trigger
- Battery out while changing the bit; bit seated and tight
- Collar on the drill symbol for drilling, a low number for driving
- Gear chosen with the drill stopped
- Work clamped, scrap behind a through hole
- A two-handed grip, side handle fitted if supplied
- Eye protection on
Sources
The steps are DEWALT's for its DCD777; another drill's manual may differ in detail, and is the one to follow. Pilot sizes are W. L. Fuller's; the lead-hole rule is the Wood Handbook's. No tool was tested.
- 1.
DCD777 Cordless Drill/Driver instruction manual (English). DEWALT.
Used for: Fitting an accessory with the battery out, inserted about 3/4 in and tightened by hand while holding the tool, never by gripping the chuck and running the motor; checking the bit is secure; the collar at the drill symbol for drilling and the clutch engaged only in screwdriving; gears selected to match the job, changed only when stopped; both hands, the auxiliary handle if supplied, otherwise one hand on the handle and one on the battery pack; clamping the work rather than holding it; pressure in a straight line, enough to keep the bit biting without stalling or deflecting it; on a stall, releasing the trigger, removing the bit and finding the cause, never pulsing the trigger; easing through the last part of the hole; a backup block for thin material; withdrawing with the motor running; continuous use in the variable-speed range avoided; for screwdriving, the lowest collar setting that seats the screw, found by practice runs in scrap; eye protection.
- 2.
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: Clearance (shank) and pilot holes by screw gauge, in hardwood and softwood, and a screw length with about a third in the piece attached and two-thirds in the piece it is attached to.
- 3.
Chapter 8: Fastenings. USDA Forest Service, Forest Products Laboratory — Wood Handbook, FPL-GTR-282, 2021.
Used for: Screws turned in, never started or driven with a hammer; the lead hole for the shank about the shank's diameter and for the threads near the root diameter, larger in proportion in dense woods.
About this tutorial
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