Budget HSS drill bit sets break 3-5 times more often than quality cobalt or titanium-coated sets when drilling steel or hardened bolts. At a working mechanic's rate of 200 holes per month, the cheap set costs 2.5x more per hole than a mid-tier cobalt set. Buying quality bit sets once is the single highest-ROI purchase in a shop's small-consumable budget.
Where the cheap sets fail
Generic HSS (high-speed steel) bits soften rapidly above 800°F. When drilling hardened steel (Grade 8 bolts, spring steel, stainless), the cutting edge temperature easily hits 1,000°F in seconds without coolant. The bit edge rolls, then rips off.
Cobalt (M35 or M42) bits hold edge hardness up to 1,100°F. Titanium-coated HSS (TiN, TiAlN) coatings raise surface hardness and reduce friction so the bit stays cooler. Either holds up on drilling work where generic HSS fails in 5-10 holes.
Cost per hole — real numbers
Budget HSS 29-bit set (~$19): average 30-50 holes in mild steel before the 3/8" or 1/4" breaks. That's the one you use most; when it breaks, the set is effectively retired. Cost per hole: ~$0.38.
Mid-tier cobalt 29-bit set (~$49, e.g., Milwaukee 48-89-2802): average 200-400 holes per common size before significant dulling. Cost per hole: ~$0.12.
Premium cobalt with red-helix (Milwaukee SHOCKWAVE Red Helix, $79 for 29-pc): average 400-800 holes per size, sustained use. Cost per hole: ~$0.10.
When HSS is fine
For drilling wood, plastic, aluminum, or brass, generic HSS is perfectly adequate. These materials don't generate enough heat to reach HSS's failure threshold.
A home DIYer drilling maybe 20-50 holes a year in mixed materials can use a $19 HSS set for 5-10 years. The break-even doesn't kick in at that volume.
The brands worth paying for
Milwaukee SHOCKWAVE Red Helix (cobalt): industry benchmark for mechanic / metal-drilling work. Holds edge longest in 1/4"-3/8" range. Fits the bit indexing most trades use.
DeWalt Extreme Titanium (TiN-coated): mid-tier priced, excellent in mixed-material drilling.
Viking Drill MDS (M35 cobalt): legacy favorite among machinists. Older name, still high quality.
Skip: no-name "Cobalt" sets from Amazon under $20. The marketing says cobalt; the actual metal is often indifferent HSS with a copper-tone flash coating.
Joshua runs Charged Tools out of St. Louis. Background spans e-commerce operations, software engineering, and hands-on tool use in the auto trades. Every editorial piece on this site is written or reviewed by Joshua before it ships.
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FAQ
Do split-point bits really drill faster?+
Yes. Split-point geometry starts cutting on contact without walking, so you skip the center-punch step. On a production job (drilling 20+ holes in flat steel), split-point saves 10-15 seconds per hole and keeps you cleaner on the layout. Cobalt SHOCKWAVE Red Helix is split-point by default.
Is step-bit better than a regular twist bit for sheet metal?+
For holes 1/8"-1-3/8" in sheet metal (14 gauge or thinner), yes — step bits produce cleaner holes, don't wander, don't grab at breakthrough. For anything thicker than 14 gauge, step bits chatter and twist bits win.
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