Choosing a Cobalt Jobber Drill Set: What Matters for Hardened Metals
When selecting a cobalt M35 drill bit set like this 60-piece #1-60 collection, buyers should understand that jobber length represents the standard ratio of flute length to diameter. This specific set's claim to handle hardened metal and stainless steel hinges on its 5-8% cobalt content in M35 high-speed steel, which provides better heat resistance than standard HSS bits.
Key Considerations Before Buying
- The #1-60 numbering system (approximately 0.228" to 0.040") offers finer gradations than fractional sets, ideal for precise tapping and clearance holes in metalworking.
- Jobber length bits provide optimal rigidity for hand drills and drill presses in most materials, but may require peck drilling for deeper holes in tough metals like cast iron.
- The included index case is crucial for protecting these cobalt bits from damage and maintaining the organized progression of 60 consecutive sizes.
What Our Analysts Recommend
Examine the grind quality—a well-sharpened 135-degree split point (common on cobalt bits) reduces walking on hardened surfaces. Check for consistent black oxide or titanium nitride coating, which reduces friction and increases tool life when drilling stainless steel. The storage case should securely hold each bit to prevent flute-to-flute contact that dulls cutting edges.
Jobber Drill Bits Market Context
Market Overview
The cobalt drill bit market is segmented between industrial-grade premium sets and more affordable consumer kits, with this 60-piece M35 set positioned as a bridge option for serious DIYers and light professionals. Jobber-length cobalt sets have become increasingly popular as homeowners tackle more stainless steel and alloy projects.
Common Issues
Lower-quality cobalt sets may have inconsistent hardness between bits or improper heat treatment, causing premature failure when drilling hardened metals. Another frequent complaint involves storage cases with poor labeling or flimsy hinges that compromise the long-term organization of numbered sets.
Quality Indicators
Genuine M35 cobalt steel should maintain a sharp edge through multiple uses on stainless steel without excessive discoloration. Quality sets feature precise size markings that won't wear off and bits that run true without noticeable wobble—critical when using smaller #60-size bits (0.040").
Review Authenticity Insights
Grade B Interpretation
A Grade B authenticity rating with 11% estimated fake reviews indicates mostly reliable feedback, though shoppers should be slightly more critical of extreme positive reviews. The adjusted 4.40 rating (down from 4.67) suggests some review inflation but still reflects genuinely positive experiences.
Trust Recommendation
Focus on reviews that mention specific applications like drilling stainless steel brackets or cast iron fittings, as these demonstrate real-world testing of the cobalt claims. Be skeptical of reviews that only praise packaging or count pieces without discussing performance on hardened materials.
Tips for Reading Reviews
Prioritize reviews that compare these M35 bits to previous HSS or titanium-coated sets, as these provide meaningful performance benchmarks. Look for mentions of the #50-60 smallest bits holding up—these typically fail first in inferior sets when drilling hard metals.
Expert Perspective
This set's strong adjusted 4.40 rating from over 2,300 reviews suggests it delivers good value for drilling hardened metals, though the authenticity analysis warrants cautious optimism. The comprehensive #1-60 progression is particularly valuable for machinists and automotive enthusiasts who need precise hole sizes rather than approximate fractions. The M35 cobalt composition should provide adequate heat resistance for intermittent use on stainless steel, though production-grade continuous use might require premium M42 cobalt bits.
Purchase Considerations
Consider whether you truly need 60 consecutive sizes or if a smaller fractional set would suffice—the #1-60 range is specialized for precision work. Evaluate your typical materials: if you primarily drill wood and plastic, standard HSS bits offer better value, but for regular stainless steel or cast iron projects, the cobalt advantage justifies the investment.
Comparing Alternatives
Shoppers should compare point geometry and case durability with similar M35 sets from Neiko, Viking, or Astro Pneumatic to ensure optimal value.
