21 Pc Drill Bit Set Index: Sizes and Uses Guide
By Drill Hog® | Published: 2026-10-26
Category: Buying Guides
Discover what's included in the 21 Pc Drill Bit Set Index from Drill Hog, plus practical advice on choosing and using hi-molybdenum M7 drill bits for metal drilling projects.
Quick answer
The 21 Pc Drill Bit Set Index from Drill Hog covers fractional sizes 1/16" to 1/2" with fine increments, plus an 8-piece Silver & Deming set for larger holes up to 1". It's built for metal drilling using hi-molybdenum M7 steel.
Why size increments matter for metal drilling
A drill bit index with tight size steps saves time and improves fit. The 21-piece set includes 1/16" to 1/4" in 1/64" increments and 9/32" to 1/2" in 1/32" steps. This range covers most common fractional hole sizes for steel and other metals without needing to ream or guess.
For larger holes, the included 8-piece Silver & Deming set provides 9/16" to 1" sizes. These bits have a reduced shank so they fit standard 1/2" drill chucks, which is a practical advantage when your drill can't accept a full 1" shank.
Hi-molybdenum M7 steel: what it means for you
M7 high-speed steel contains molybdenum, which improves heat resistance and wear life. Hi-molybdenum M7 is a step above standard HSS for drilling harder metals like stainless steel and alloy steels. It holds an edge longer than lower-grade bits, reducing the need for frequent resharpening.
That said, M7 is not as hard as cobalt M42 bits, so if you regularly drill through hardened steel or abrasive materials, you may want a cobalt set. For general metalworking, fabrication, and maintenance drilling, M7 offers a good balance of performance and cost.
Trade-offs of a combined index + Silver & Deming set
Having two sets in one package covers both small and large holes, but the index case is designed for the 21-piece set only. The Silver & Deming bits are loose, so you'll need a separate storage solution or pouch. If you prefer everything in one indexed case, this combination may require extra organization.
On the plus side, you get 29 bits total for a price that is often lower than buying the sets separately. The catalog comparison price of USD 297.00 versus the actual price of USD 210.87 reflects that value.
How to choose and use this drill bit set
- Check your most common hole sizes: If you frequently drill holes between 1/16" and 1/2", this set covers nearly every fractional size you'll need. For holes larger than 1/2", the Silver & Deming set handles 9/16" to 1".
- Match the material to the bit grade: Use hi-molybdenum M7 bits for mild steel, stainless steel, aluminum, and brass. For hardened steel or abrasive composites, consider cobalt M42 bits instead. M7 is not the hardest option, but it's a solid choice for most metal drilling jobs.
- Plan storage for the Silver & Deming bits: The index case holds only the 21-piece set. Keep the eight larger bits in a separate pouch or roll to avoid losing them. A simple labeled pouch or magnetic strip works well.
- Use cutting fluid for longer bit life: M7 steel benefits from lubrication when drilling metal. Apply a few drops of cutting oil to reduce heat and prevent work-hardening, especially in stainless steel. This simple step can double the life of your bits.
Product facts
- 21 Pc Drill Bit Set Index + 8 Pc Silver & Deming Hi-Molybdenum M7 Drill Hog®: Includes 21 fractional sizes from 1/16" to 1/2" with 1/64" increments up to 1/4" and 1/32" increments from 9/32" to 1/2". You can drill precise holes without stepping up to a reamer, which is especially useful for close-tolerance metal work.
21 Pc Drill Bit Set Index + 8 Pc Silver & Deming Hi-Molybdenum M7 Drill Hog® - 21 Pc Drill Bit Set Index + 8 Pc Silver & Deming Hi-Molybdenum M7 Drill Hog®: Also includes an 8-piece Silver & Deming set in sizes 9/16" to 1" with reduced shanks. These larger bits fit standard 1/2" drill chucks, so you don't need a special drill to bore holes up to 1" diameter.
- 21 Pc Drill Bit Set Index + 8 Pc Silver & Deming Hi-Molybdenum M7 Drill Hog®: Made from hi-molybdenum M7 high-speed steel. M7 steel offers better heat and wear resistance than basic HSS, making it suitable for drilling steel and stainless steel without rapid dulling.
Who should buy this set
Best for
- Metal fabricators and machinists who need a wide range of fractional sizes in one purchase
- Maintenance technicians who drill steel, stainless steel, and aluminum regularly
- Hobbyists who want a single set that covers both small and large holes without buying separate kits
Not ideal for
- Users who need metric sizes exclusively (this set is fractional only)
- Drilling hardened steel or abrasive materials regularly (consider cobalt M42 bits instead)
- Anyone who wants all bits stored in one indexed case (Silver & Deming bits are loose)
