Most DIYers own a drill and assume the impact driver is just 'a stronger drill.' It isn't. The two tools work fundamentally differently — and using one when you should use the other strips screws, splits wood, or burns out the drill. Match the tool to the task and screws drive cleanly, holes drill cleanly, and your tools last.
This guide explains when to use each, what bits work in which, and the common mistakes.
Before you start
Three things to settle:
1. The mechanism is different. Drill: continuous rotation. Slower torque builds, lower max torque. Best for drilling holes (rotation is what cuts) and driving small fasteners. Impact driver: rotation + sudden percussive 'impacts' (hammering rotational blows) when load increases. High torque, but pulsed.
2. Bit shanks differ. Drill bits: round shank (hex shank also works). Impact driver: 1/4 inch hex shank only — round-shank bits won't fit, and standard drill bits aren't rated for the impact mechanism's stress. Always use impact-rated bits in an impact driver.
3. Match tool to task. Hole drilling, sensitive driving (small screws into trim): drill. Driving long screws, lag bolts, large fasteners: impact driver. Driving sheet-metal screws into thin material: drill (impact will strip).
What you'll need
Tools
- Drill (cordless, 18-20V typical)
- Impact driver (cordless, 18-20V)
- Drill bits (twist, spade, hole saw — round or hex shank)
- Impact-rated driver bits (1/4 inch hex shank)
- Compatible batteries and charger
Materials
- Screws (gauge appropriate to project)
- Pre-drill bits (smaller than screw shank)
- Drill bit set (standard)
- Impact driver bit set (Phillips, square, Torx)
Use impact-rated bits in an impact driver
Standard driver bits in an impact driver shatter under repeated impact. Look for 'impact-rated' or 'impact-ready' on the package.
A small set is inexpensive and well worth it — broken bits in a screw head are a pain to remove.
Step-by-step instructions
Pick the right tool
Drilling holes: drill, with appropriate twist or spade bit.
Driving small or fine-thread screws (under 1.5 inch): drill.
Driving long deck screws, lag bolts, or large fasteners (1.5 inch+): impact driver.
Driving in tight spaces (compact head): impact driver, smaller body.
Pre-drill pilot holes (drill task)
For most screws into hardwood: pre-drill a hole slightly smaller than the screw shank.
Prevents splitting and reduces stripping.
Soft pine and small screws: often skip pre-drill.
Insert the right bit
Drill: chuck open, insert bit, tighten chuck (3-jaw self-tightening on most modern cordless drills).
Impact driver: pull collar back, insert bit, release. Bit locks via 1/4 inch hex retention.
Always confirm bit is fully seated.
Set torque/clutch (drill only)
Drills have a clutch ring with numbered torque settings.
Lower number: clutch slips before over-driving.
Higher number: more torque before slipping.
Drill mode (icon of drill bit): no clutch — for drilling holes only.
Test on scrap before driving into final.
Drive the screw
Position bit in screw head. Press firmly — slipping the bit out strips the screw head.
Squeeze trigger gradually, increasing speed.
Drill: clutch will slip when screw is set — release trigger.
Impact driver: feel for the rotational pulses (impacts kick in when load increases). Release when screw is flush or slightly recessed.
Don't over-tighten
Drill: clutch limits over-tightening but only if you set it correctly.
Impact driver: high torque can break screws or strip threads. Stop when flush.
Power off the moment the screw seats.
Match bit to screw head type
Phillips: most common but cams out (slips) easily.
Square (Robertson): popular in Canada, less cam-out.
Torx (star): least cam-out, used for premium hardware.
Use the matching bit; mixing strips heads.
Maintain bits and tools
Worn bits cam out. Replace at first sign of rounding.
Battery management: don't fully discharge before charging — modern lithium-ion likes partial cycles.
Store tools dry, batteries separate.
Common mistakes that cost you
- Using standard drill bits in impact driver. Hex shank required. Standard drill bits in impact driver = broken bits.
- Driving lag bolts with a drill. Drill burns out under sustained high torque. Use impact driver.
- Driving small screws with impact driver. Strips heads, splits wood, drives too far. Use drill with clutch.
- Skipping pilot holes in hardwood. Wood splits or screw breaks. Pre-drill for hardwood.
- Wrong screwdriver bit. Phillips bit in Robertson screw cams out and strips. Match bit to head type.
Frequently asked questions
Can I drill holes with an impact driver?
Only with hex-shank impact-rated drill bits.
Even then, drilling is less precise than with a drill — the impact mechanism kicks in during the cut, making the bit jump.
For accurate holes, use a drill.
Should I buy a combo kit?
Yes — for most renovation work, you'll use both. Combo kits include drill, impact driver, two batteries, charger.
Mid-tier brands (DeWalt, Milwaukee, Makita) are a sensible middle ground.
One battery platform — buy more tools later.
Do I need both for a one-time renovation?
If just hanging some shelves: drill is enough.
If building a deck, framing, or driving lots of fasteners: impact driver saves your wrist.
Rental: combo kits are available by the day at most rental stores.
When to call us instead
Our crews use professional-grade tools with appropriate bits and torque settings. Right tool for the job, every time.
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