Step Drill Bits vs Unibit: Which Should You Buy?
By Drill Hog® | Published: 2026-10-17
Category: Comparisons
Compare step drill bits and Unibit-style reamers. Learn the key differences, tradeoffs, and which type suits your electrical or metalworking jobs.
Quick answer
Step drill bits and Unibit-style reamers both cut multiple hole sizes with one tool, but they differ in flute design, material, and intended use. A spiral flute step bit like the Drill Hog Cobalt M42 set clears chips faster in deep metal, while a standard Unibit works well for thin sheet metal and electrical boxes. Your choice depends on the material thickness and how often you drill overhead or in tight spots.
Flute design and chip evacuation
A standard Unibit typically has straight flutes that cut a clean edge but can clog when drilling deeper than the first step. Spiral flute step bits, such as the Drill Hog Cobalt M42 step drill bit set, use a twisted design that pulls chips upward and out of the hole. This makes spiral flute bits better for thicker materials like steel angle or conduit where chip buildup slows you down.
Material and durability
Step bits made from cobalt M42, like the ones in the Drill Hog set, hold their edge at higher temperatures and resist wear better than standard HSS step bits. If you frequently drill stainless steel or hardened metals, cobalt M42 is a worthwhile upgrade. For occasional work in aluminum or plastic, a standard HSS Unibit is sufficient and more affordable.
Tradeoffs at a glance
- Spiral flute vs straight flute: Spiral flute step bits eject chips upward, reducing clogging in deep holes. Straight flute Unibits cut a smooth edge but require frequent clearing in thicker material. Choose spiral flute for deep or blind holes; choose straight flute for thin sheet metal.
- Cobalt M42 vs HSS: Cobalt M42 retains hardness at high temperatures, lasting longer in stainless or hardened steel. HSS is cheaper and works well for softer metals and plastic. Invest in cobalt M42 if you drill metal daily; save with HSS for occasional use.
- Step range and increments: A three-bit set like the Drill Hog Cobalt M42 covers 3/16" to 1-3/8" with fine steps, reducing the need to swap bits. Single Unibits often cover a narrower range with larger steps. A multi-bit set gives you more versatility without carrying extra tools.
Product facts
- Electrician Step Drill Bit UNIBIT Reamer Spiral Flute COBALT M42 Drill Hog USA: Drill Hog Cobalt M42 Step Drill Bit Set Spiral Flute includes three bits covering 3/16" to 1-3/8" with step increments as fine as 1/16". The spiral flute clears chips automatically, and the cobalt M42 material handles high heat without dulling quickly, making this set ideal for electricians and metal fabricators who drill many holes in a row.
- Monster Booster Cables 2 Gauge 25 Foot Parrot Jaw Clamps: Monster Booster Cables 2 Gauge 25 Foot Parrot Jaw Clamps are rated 600 amps and include cold-weather jackets rated to -20 degrees. While not a drill bit, these booster cables complement a workshop setup by providing reliable jump-starting power in cold conditions, so you can keep your tools running on job sites.
Which one fits your work?
Best for
- Electricians who need clean holes in electrical panels and junction boxes
- Metalworkers drilling thick steel or stainless steel where chip evacuation matters
- Anyone who wants one tool to handle multiple hole sizes without changing bits
Not for
- Woodworkers who need very deep holes beyond the step bit's flute length
- Users who only drill soft materials and prefer a lower-cost single bit
