A step drill bit is one of those tools you don’t fully appreciate until you’ve tried to drill three progressively larger holes with three separate bits. Then it clicks. Step bits stage a single conical tip into a ladder of cutting diameters, so you punch clean, round, burr-free holes in thin metal, plastic, and even wood without swapping tools, without pilot holes, and without the slow walk a standard twist bit takes across sheet steel. The 2026 lineup is broader than ever, from plumber-grade giants built for 1-3/8″ conduit knockouts to compact 1″ mini-bits that slip into electrical box corners. What follows is a curated shortlist built around real use cases, with notes on shank fit, coatings, and the trade-offs that actually matter on the job.
The Lineup, Simplified
Greenlee GSB12 1-3/8″ Step Bit (#12) Metal Cutter
toolant M35 Cobalt Step Drill Bit, 1/4″-1-1/8″, TiAlN
DEWALT Step Drill Bit Set, 7/8-Inch to 1-1/8-Inch (DWA1789IR)
3/16-7/8 Impact Step Drill Bit, #4
Lenox Vari-Bit 7/8-In to 1-3/8-In #12 Step Drill Bit
Klein Tools KTSB15 Step Drill Bit #15, 7/8 to 1-3/8-Inch
Klein Tools Step Drill Bit #15 and 7-in-1 Flip Socket Set
toolant Mini Step Drill Bit, 1/8″-1/4″, M2 HSS
Meet The Standout Selections
Greenlee built the GSB12 for the people drilling real conduit knockouts on real jobs: electricians, plumbers, and HVAC techs who knock out 1-3/8″ holes all day and can’t afford a wandering tip. The split-step geometry and dual-flute layout start fast and stay straight on round, clean, accurate holes in mild steel, aluminum, brass, copper, wood, fiberglass, and laminates.
At 1-3/8″ final diameter and a 1/2″ shank, it fits most half-inch corded and cordless drill chucks, plus common magnetic drill presses. For most homeowners it’s overkill, but for trade work it’s the kind of bit you buy once and reach for every week.
Strong Points
- Patented split-step tip starts cleanly and resists walking, even on slick metal
- Stages up to 1-3/8″ in one pass, so a single bit replaces a stack of hole saws
- Wide material compatibility covers steel, copper, aluminum, plastics, and wood
- 1/2″ round shank works with standard drill chucks, not just specialty drivers
Worth Noting
- Size limits it to bigger conduit and box-work applications, so it sits idle on finer electrical tasks
- Owners commonly report a heavier cut feel in 16-gauge steel, and the bit can heat up quickly without steady feed pressure
Who It Suits Best
Plumbers, electricians, and HVAC installers running 1-3/8″ knockouts in metal enclosures or conduit panels day after day.
Where Another Pick Suits Better
If your work is mostly smaller electrical holes in junction boxes, the toolant Mini Step Drill Bit is a tighter fit and far easier to control in cramped panels.
Where the Greenlee dominates large knockouts, this toolant bit dominates harder alloys. M35 cobalt steel (a high-speed steel alloyed with cobalt for heat resistance) keeps its hardness at the elevated temperatures that come with sustained cutting, and the TiAlN coating (titanium aluminum nitride, a thin ceramic layer that reduces friction and adds wear resistance) helps the four-flute design slice through stainless and harder steels without glazing.
The 3/8″ hex shank locks into impact drivers and keyed chucks without slippage, so the bit feels planted rather than rolled. For fabrication shops and serious DIY metalworkers, it pulls double duty on stainless sheet and thick aluminum plate.
What It Does Well
- M35 cobalt body holds up to the heat of stainless and thick plate
- Four-flute geometry evacuates chips faster, reducing binding in deeper cuts
- TiAlN coating lowers friction and extends working life in abrasive materials
- 3/8″ hex shank prevents slippage in both impact drivers and three-jaw chucks
- Reaches 1-1/8″ final diameter, covering most common hole sizes in steel and aluminum fabrication
Points To Note
- Cobalt content makes the bit harder to resharpen than standard HSS (high-speed steel), so once it dulls, replacement is the practical answer
- For soft materials like wood or thin plastic, the premium body is more than the job needs
Made For
Fabricators and metalworkers cutting stainless, hardened alloys, or thick aluminum on a regular basis.
Swap It Out When
If your workload is mostly 1/4″ to 7/8″ holes in mild steel and electrical enclosures, the 3/16-7/8 Impact Step Drill Bit covers a more useful range at a friendlier price.
DEWALT engineered the DWA1789IR specifically for impact drivers, which generate punishing torsional pulses (short bursts of twisting force from the hammer mechanism inside the tool) that snap standard bits in half. The split-point tip launches into sheet metal without skating, and the titanium-nitride coating (a gold-colored ceramic surface that reduces friction) keeps the two-flute spiral sharp over thousands of holes. The 1/4″ hex shank sits deep in the collet, so the bit stays rigid under load.
For cordless crews running 20V max impact drivers, the laser-engraved step numbers read cleanly even with chip spray and low light, which is the kind of detail that matters when you’re sizing a hole by feel on a live jobsite.
What Works In Its Favor
- Impact-rated construction survives the hammer pulses of cordless impact drivers
- Titanium-nitride coating helps the cutting edges last through repeated sheet-metal work
- Two-flute spiral clears chips efficiently, reducing the heat that warps thin flutes
- Laser-engraved step numbers stay readable under shop grime
Honest Caveats
- Range tops out at 1-1/8″, so larger knockout work falls outside its scope
- The split-point tip walks less than some competitors but still benefits from a center punch on curved or polished surfaces
Best Suited To
Cordless-tool crews and electricians who size conduit holes from 7/8″ to 1-1/8″ in steel electrical boxes.
Not Your Match When
If you need the same range in 1/2″ round-shank form for a corded drill, the Greenlee GSB12 1-3/8″ Step Bit covers a broader diameter range with a chuck-friendly shank.
The Rapid Strike Tip on this bit, with its dual spiral flutes (twin helical grooves that lift chips out of the cut), is built for volume work. Where most step bits bog down in thicker gauge steel, this design uses an optimized shock zone, a thicker neck section that absorbs the hammer blows from impact drivers, plus a titanium-aluminum-nitride coating to push hole counts well past standard tooling.
At a 3/16″ start and 7/8″ top, the range is the everyday sweet spot for electrical boxes, service panels, and small chassis work. It pulls double duty in impact drivers and standard keyless chucks, so you don’t need a special tool to run it.
Well-Handled Touches
- Dual-spiral flute design moves chips out fast, which matters when you’re drilling hole after hole
- Rapid Strike Tip reduces the bit skating that ruins thin sheet metal on the first pass
- Optimized shock zone resists snapping under high-torque impact pulses
- Coated cutting edges hold their geometry through high-volume runs
- 3/16″ starting diameter covers pilot-sized holes without a separate bit
Trade-Offs
- Caps at 7/8″, so conduit knockouts and 1″ pipe work fall outside its range
- High coating hardness means re-sharpening is impractical; once dull, replacement is the realistic path
Who Will Love This
High-volume electricians and panel builders who drill dozens of holes a day and want one workhorse bit that survives the abuse.
Consider Something Else When
If your holes climb above 7/8″ or you want a bit that handles larger conduit, the DEWALT Step Drill Bit Set (DWA1789IR) extends the range to 1-1/8″ with similar impact-rated construction.
Lenox’s Vari-Bit is a workshop classic for a reason. The patented two-flute design pulls clean, round holes without chatter, and the split-point tip starts the cut where you place it. The steam-oxide finish (a dark oxide layer bonded to the steel during heat treatment, which helps retain cutting-fluid binding and reduces friction) holds up to repeated heat cycles without flaking, and the flute geometry clears chips quickly so the bit doesn’t grab on the back side of the cut.
It covers 7/8″ to 1-3/8″ in even stages, the same size family used for plumbing stacks, dryer vent cuts, and HVAC penetrations. Most contractors who’ve run one keep it in the service truck for years.
A Strong Showing
- Patented two-flute design cuts rounder, cleaner holes than typical three-flute bits
- Split-point tip reduces walking on slick metal, which speeds up layout work
- Steam-oxide finish holds cutting fluid and resists heat-checking
- Stages cover the full 7/8″ to 1-3/8″ plumbing and HVAC size range
Potential Drawbacks
- No TiAlN or titanium-nitride coating, so heavy production runs may dull it sooner than coated competitors
- The 3/8″ round shank won’t lock into 1/4″ impact drivers without an adapter
Right Fit For
Plumbing and HVAC contractors drilling vent, drain, and stack penetrations in thin sheet metal and ductwork.
A Better Fit Elsewhere
If your work is mostly smaller electrical holes in boxes, the Klein Tools KTSB15 Step Drill Bit offers the same range with laser-etched size markings and a hex shank for impact drivers.
Klein builds for electricians, and the KTSB15 shows it. The aluminum-titanium-nitride coating (AlTiN, a wear-resistant ceramic layer that holds up under high heat) extends bit life well past standard black-oxide finishes, and the laser-etched size markings stay visible even after months of pouch wear and shop grime. The two straight flutes clear chips cleanly and produce rounder holes than most spiral-flute designs in this range.
The 3/8″ hex shank locks into both standard chucks and impact drivers, which matters for trade users who swap between tools throughout the day. It’s a refined tool where the details add up.
Key Advantages
- AlTiN coating dramatically extends working life compared to steamed black oxide
- Laser-etched step markings stay readable in low light and after repeated cleaning
- Two straight flutes produce clean, round holes in mild steel up to 16 gauge
- 3/8″ hex shank works in both impact drivers and standard keyless chucks
- 3-hole size progression covers the most common electrical box and panel sizes
Things To Consider
- Range starts at 7/8″, so smaller 1/2″ and 3/4″ knockouts need a different bit
- Coated edges resist sharpening, so dulling means replacement rather than a quick touch-up
Perfect Match For
Electricians who want legible size markings, durable coating, and a bit that survives daily pouch-and-belt abuse.
Look Elsewhere When
If you want the same Klein step bit bundled with an impact socket set for a starter kit, the Klein Tools Step Drill Bit #15 and 7-in-1 Flip Socket Set covers both needs in one purchase.
This bundle pairs Klein’s #15 step bit with a 7-in-1 impact flip socket that holds six hex driver sizes plus a 1/4″ bit driver. For apprentices, homeowners building a starter kit, or anyone who needs both a knockout bit and a versatile driver, the combination covers more ground than a standalone step bit. The step bit itself mirrors the KTSB15 above, with the same AlTiN coating and laser-etched markings.
It’s not a deep-discount package, and the flip socket won’t replace a full set, but the value is in the convenience of grabbing one bundle instead of tracking two separate purchases.
Notable Gains
- Aluminum-titanium-nitride step-bit coating holds up well in 16-gauge steel
- Two straight flutes pull chips out cleanly, reducing heat buildup
- Flip socket covers six common hex sizes, useful for assembly and disassembly work
- 1/4″ bit driver in the flip socket adds a screwdriver function for fastener work
- Bundle simplifies stocking for new tool users or trade-school kits
Trade-Offs
- Pays a premium over buying the step bit alone, so experienced tool owners may already own equivalents
- The flip socket covers only hex sizes, so Torx or specialty fasteners require a different driver
Built With In Mind
Apprentices, homeowners, and trade students building a foundational electrical and driving tool kit on a single purchase.
Reach For A Different Pick When
If you already own a complete socket set and only need the step bit, the Klein Tools KTSB15 alone gives you the same cutting performance without the bundle premium.
Standard step bits are too long for cramped electrical boxes, low-voltage cabinets, and tight panel work. The toolant Mini steps in with a roughly 1″ body and a sub-50mm total length, so it fits where a full-size bit simply won’t. The 1/4″ hex shank drops into any impact driver or keyless chuck, and the M2 HSS (a tungsten-molybdenum high-speed steel known for toughness) body handles 1/8″ to 1/4″ holes in mild steel, plastic, and thin aluminum.
It’s a specialty pick, but the right one for control work where the standard ladder bit blocks your line of sight or hits a panel wall.
Real-World Strengths
- Sub-50mm body fits where standard step bits physically cannot reach
- 1/4″ hex shank works in any impact driver or keyless chuck
- M2 HSS construction stays sharp through repeated small-diameter work
- 1/8″ to 1/4″ range covers pilot holes, small wire pass-throughs, and pilot drilling
- Dual-angle cutting edge design helps the bit start cleanly on slick surfaces
Some Limits To Know
- Range tops out at 1/4″, so it cannot replace a full-size bit for electrical boxes
- Short shank reduces leverage in deeper cuts, so it works best on thin sheet rather than thick plate
Whose Shelf It Belongs On
Electricians, low-voltage installers, and cabinet makers who regularly drill in tight enclosures where a standard step bit is too long to use.
Where A Sibling Pick Shines
For larger knockout work beyond 1/4″, the 3/16-7/8 Impact Step Drill Bit covers the everyday electrical range with more aggressive material removal.
Matching The Right Step Bit To Your Work
A step bit earns its place in your kit when its size range matches the holes you actually drill. Most electrical work happens in 7/8″ to 1-3/8″ territory, which is where the Greenlee, Lenox, Klein, and DEWALT picks cluster. Plumbing and HVAC also live in that band, while fabrication shops often need cobalt toughness for stainless, where the toolant M35 picks up the load.
Shank And Chuck Fit
Step bits come in two shank types: round and hex. Round shanks (typically 1/4″ or 3/8″) need a three-jaw chuck (the geared collar with three movable jaws that grips cylindrical shanks) and work in any corded or cordless drill. Hex shanks (1/4″ or 3/8″) lock into impact drivers and quick-change systems, and they resist slippage under high torque. Pick the shank your drill can accept, and confirm the shank size before you buy.
Coatings And Materials
Coatings change the bit’s life span, not its cutting ability. Steam-oxide finishes (the dark surface on bits like the Lenox Vari-Bit) are affordable and decent. Titanium-nitride (TiN, a gold-hued ceramic) and titanium-aluminum-nitride (TiAlN) coatings add a ceramic layer that reduces friction and heat. Cobalt M35 bodies are the toughest choice for stainless and hardened alloys, but they’re more brittle and harder to resharpen.
Step Count And Diameter Range
Each “step” on a step bit is a fixed diameter. More steps mean finer size selection but a longer bit. A 9-step bit from 1/4″ to 1-1/8″ gives you almost any hole size in that range, but it’s a longer tool. A 3-step 7/8″ to 1-3/8″ bit is compact and fast for plumbing and box work, but you can’t size in between.
Drive Tool Compatibility
Impact drivers deliver hammer-style pulses, which crack standard step bits quickly. Bits labeled “impact rated” or “impact ready” have thicker necks and tougher flutes designed for that abuse. Corded drills and regular cordless drill-drivers are gentler and work with most bits, including non-impact-rated designs.
What To Watch Before You Click
Common Buying Slip Ups
The most frequent mistake is buying a bit whose range doesn’t overlap your most common hole size. A 1/4″ to 1-1/8″ cobalt bit is great until you need a 1-1/4″ knockout. The second trap is ignoring the shank: a 3/8″ hex bit won’t seat in a 1/4″ impact driver. A third is overcoating, where a TiAlN bit on soft wood or plastic adds cost without performance gain. Match the bit to the material, not the marketing.
Why Higher Tier Models Cost More
Premium step bits cost more because of their steel and coating. M35 cobalt resists the heat that softens standard high-speed steel during long cuts in stainless. TiAlN and AlTiN coatings add wear resistance that extends life in production runs. Steam-oxide finishes are cheap and adequate for occasional use, while coated cobalt bits are built for daily, high-volume drilling. The upgrade pays off when you actually run the bit hard; for a once-a-month project, the entry-level pick is plenty.
