Standard Drill Bit Size: Chart for Choosing a Set
The sets in this guide run from 1/16 to 1/2 inch in fractional sizes and 1.5 to 6.5 mm in metric sizes, and the right size is the one that matches the hole and the material.
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A shelf bracket that needs a fresh hole, a hinge that has worked loose, a bolt that has to pass through a steel plate: the job stalls when the bit in the chuck does not match the hole you need. Standard drill bit size is the range of common fractional and metric sizes sold in sets, and the right one is the size that matches the hole or the fastener the job calls for.
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Below: what the standard sizes cover, how to match a bit to the job, and the sets that cover the range.
Sinyeenglon Cobalt Drill Bits Set for Hardened
A 122-piece M35 cobalt twist bit set covering 1/16 to 1/2 inch in 19 sizes, with an index storage case, listed for hardened metal and stainless steel.
Pros
- 122 pieces across 19 sizes from 1/16 to 1/2 inch
- M35 cobalt with hardness up to 67, listed for stainless steel and hardened metal
- Maker claims up to 12 times the life of an average HSS titanium coated bit
- Index case with sizes printed on the bottom of the lid for quick access
Cons
- No warranty term is stated on the listing
- No safety certification is stated
- Only 2 pieces each of the 3/8, 7/16 and 1/2 inch sizes
- Shank type is not stated
19 Pcs HSS Titanium Twist Drill Bit Set
A 19-piece titanium-coated HSS twist bit set in 13 metric sizes from 1.5 to 6.5 mm, with a 1/4 inch hex shank and a 135 degree split point.
Pros
- 135 degree split point self-centers without a pilot hole
- 1/4 inch hex shank locks into quick-change chucks and impact drivers
- 13 metric sizes from 1.5 to 6.5 mm, with a backup piece for six common sizes
- Titanium-coated HSS listed for mild steel, carbon steel, sheet metal, wood and plastics
Cons
- No warranty term is stated on the listing
- No safety certification is stated
- Largest size is 1/4 inch, so bigger holes need a larger set
- Not listed for stainless steel or hardened metal
Standard drill bit size: what the sizes cover
The Sinyeenglon set lists sizes from 1/16 inch to 1/2 inch across 122 pieces in 19 sizes, while the YXYL set lists 13 metric sizes from 1.5 mm to 6.5 mm, matching 1/16 inch to 1/4 inch, in 19 pieces. The range, not any single bit, is what the standard means.
| Set | Size range | Pieces |
|---|---|---|
| Sinyeenglon Cobalt Set | 1/16 to 1/2 inch | 122 |
| YXYL Titanium Hex Set | 1.5 to 6.5 mm (1/16 to 1/4 inch) | 19 |
The counts inside a set are not even. The Sinyeenglon listing gives 30 pieces of the 1/16 inch size, 20 pieces of 5/64 inch, 10 pieces each of 3/32 inch and 1/8 inch, and 2 pieces each of 3/8 inch, 7/16 inch and 1/2 inch. The YXYL listing gives six common sizes a backup piece each.
How to match a standard drill bit size to the job
Start from the hole, not the set. A clearance hole takes a bit at least the size of the shank of the bolt or screw, so the fastener passes through. A pilot hole takes a bit smaller than the fastener, so the threads still grip. When the fastener maker gives a size for the job, use that size; otherwise check each bit against the fastener, using a bit at least the size of the shank for a clearance hole and a smaller bit for a pilot hole.
The material narrows the bit choice. The Sinyeenglon set is M35 cobalt, listed for stainless steel, cast iron, zinc alloy, hard sheet, flat bar, mild steel tube, titanium, aluminum, hardened metal, plastic and wood. The YXYL set is titanium-coated HSS, listed for mild steel, carbon steel, sheet metal, solid wood and plastics. Pick the set whose listed materials include the one you are drilling.
Shank shape decides fit, and point shape decides how the bit starts. The YXYL bits have a 1/4 inch hex shank that locks into quick-change chucks and impact drivers, and a 135 degree split point the listing says self-centers without a pilot hole. The Sinyeenglon bits are jobber twist bits in an index case, with each size printed on the bottom of the lid, so the size you need is easy to find and put back.
Compare the full ranges in our best drill bit sets and the guide to types of drill bit before you buy, and check the bit maker’s guidance for the materials each set covers.
Use rated jack stands on solid ground, wear eye protection with power and air tools, keep fuel-burning equipment out of a closed garage, and follow the manual for every tool. Read our Safety Disclaimer.
Drilling metal throws chips and dust, so wear eye protection and keep hands clear of the bit while it turns.
Drill bit sets that cover the standard sizes
Both sets below cover the range above, one in cobalt for hard metals and one in titanium-coated HSS with a hex shank for quick changes.
FAQ: garage tools
What is the standard drill bit size for a home garage?
There is no single standard size: the fractional set here runs from 1/16 inch to 1/2 inch and the metric set runs from 1.5 mm to 6.5 mm, so the standard is the range, not one bit. Pick the size that matches the hole the job needs, and keep a set that covers the range rather than a single bit.
What size drill bit do I need for a pilot hole?
Match the bit to the fastener: a pilot hole bit is smaller than the screw or bolt shank so the threads still grip, while a clearance hole bit is at least the size of the shank so the fastener passes through. When the fastener maker gives a size for the fastener, use that size; otherwise check each bit against the fastener, using a bit at least the size of the shank for a clearance hole and a smaller bit for a pilot hole.
Are metric or fractional drill bit sizes better?
Neither is better on its own: the fractional sizes here, from 1/16 inch to 1/2 inch, suit hardware sized in inches, and the metric sizes here, from 1.5 mm to 6.5 mm, suit hardware sized in millimetres. The YXYL set lists both, with metric sizes matching 1/16 inch to 1/4 inch, so one set can cover small holes in either system.
What does a 135 degree split point do?
The YXYL listing states that its 135 degree split point self-centers without a pilot hole and makes clean, burr-free holes with minimal chatter. That matters when the bit has to start on a smooth metal surface without wandering.
Do I need cobalt or titanium drill bits?
It depends on the material: the Sinyeenglon M35 cobalt set is listed for stainless steel, cast iron, hardened metal and titanium, while the YXYL titanium-coated HSS set is listed for mild steel, carbon steel, sheet metal, solid wood and plastics. For hard metals, pick cobalt; for general home drilling, pick the titanium-coated set.
Related: best drill bit sets, best drill bits for steel, types of drill bit and best step drill bits.
