Premium HSS Number Drill Bits (#51–#80)

Premium HSS Micro Drill Bits, Number Sizes #51 to #80

Sizes range from #51 through #80, with each size sold in a pack of 12 using the dropdown selector.

Extremely small number size / wire gauge drill bits built for precision work where standard and even larger number sizes are too large. These small high speed steel micro drill bits are made for precision drilling in a range of materials and are great for drilling mild steel. They’re durable and built to handle high speeds and high heat.

Ground from solid and ready to outlast and outperform. This line is made with a 135° split point for clean starts with less walking. If you need the point style confirmed on a specific micro size, call us at 800-350-8665.

Most of our number drills ship in a black and gold finish, and some of the smaller sizes are still black oxide. The finish helps reduce friction and heat so the edge stays sharp longer, and black oxide also helps the bits resist rust and corrosion.

When accuracy matters at a small scale, number drills are the go-to choice.

Common Uses for Micro Drill Bits

• Micro drilling and micro tap drill sizing
• Small fasteners and fine threads
• Electronics and detailed fabrication
• Precision hole work

Small Diameter Notice

Sizes #51 to #80 are very small and require proper technique:

• Use light pressure
• Avoid side loading
• Use proper RPM
• Best used in drill presses or controlled setups

Improper use can cause breakage due to the small diameter.

Tap Drill Sizes for Miniature Threads

Small number drills are the usual choice for tapping miniature machine screw threads.

• 000-120 tap: #71 drill
• 00-90 tap: #65 drill
• 0-80 tap: #56 drill (3/64″ also works)
• 1-64 tap: #53 drill
• 1-72 tap: #53 drill

Tapping 2-56 or larger? Those tap drills start at #50 on our #1 to #50 number drill bits page. Need the full list? Download our number drill tap chart (PDF) or the drill size conversion chart (PDF).

Micro Drill Size Chart: Decimal, Flute and Overall Length

Every size is sold as a pack of 12. Flute and overall lengths are standard jobber length.

QTY: 1 = pack of 12

Micro Drill Bit FAQ

What are micro number drill bits?

They’re the smallest wire gauge sizes, #51 (.067″) down to #80 (.0135″). Number sizes run backwards, so the higher the number, the smaller the bit. Everything from #53 down is smaller than 1/16″. For #1 to #50, see our number drill bits #1 to #50.

What size drill do I use for a 0-80 tap?

A #56 drill (.0465″), or 3/64″. For 1-64 and 1-72, use a #53. For 00-90, use a #65.

Will these fit in a regular drill chuck?

Check your chuck’s minimum capacity. Many standard chucks won’t close down far enough to hold the smallest sizes. A pin vise, precision drill chuck or collet works better at this size.

Are small HSS drill bits good for metal?

Yes. These are made for precision drilling in a range of materials and are great for mild steel. At this size breakage is the main risk, so use light pressure, proper RPM and clear chips often. For harder metals, look at our cobalt wire gauge drill bits (#51 to #60).

Need More Options?

• Larger number sizes: number drill bits #1 to #50
• Every micro size in one index: #61 to #80 micro drill bit set
• Sizes above #1: letter size drill bits A to Z
• Harder metals: cobalt wire gauge drill bits (#51 to #60 overlap with this page)
• Tap and drill in one kit: 18 piece SAE UNC/UNF tap and drill set

Questions on sizing or bulk orders? Call DrillBitWarehouse.com at 800-350-8665.