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Best Drill Bit For 5 16 Tap

Tom Woodward

Senior reporter

★★★★★5.0

500+ views

Today

6 min read

Looking for the best drill bit for 5 16 tap in March 2026? We reviewed 8 popular options from brands like BOSCH, RURITKIT, Century, DEWALT, IVY, Greenlee, Bestgle, Irwin and compared them on the things that matter most: build quality, comfort, ease of use, durability, and overall value. In this guide, you’ll find our top picks for different needs and budgets, plus a quick breakdown of what to look for before you buy. If you want a drill bit for 5 16 tap that performs well and holds up over time, this shortlist will help you choose with confidence.

Our Top Picks

Best Overall

BOSCH BDT516F18 5/16-18 Plug Tap and Size F Drill Bit Combo Set

★★★★★★4.8

Exact Diameter:5/16 inch diameter

Material Grade:High carbon steel

Tip Geometry:No-skate tip

Shank Compatibility:Standard chuck shank

Length & Flute Design:1.5 inch length, full flute

Surface Coating:Black oxide coating

Bosch’s no‑skate plug tap paired with a matching F drill delivers precise 5/16‑18 threads and lasting durability.

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Best Value

RURITKIT 5/16"-18 UNC Tap and F Drill Bit Kit, M2 HSS Drill and Tap Set, Combination of Drill and Tap Kit for Metal

★★★★★★4.8

Exact Diameter:5/16 inch diameter

Material Grade:M2 steel, titanium plated

Tip Geometry:Standard twist tip

Shank Compatibility:Round shank universal

Length & Flute Design:2 inch length, full flute

Surface Coating:Titanium plating coating

RURITKIT’s M2 HSS tap and titanium‑plated F drill offer high hardness, versatile metal compatibility, and compact storage.

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Best Premium

Century Drill & Tool 95405 5/16-18 NC Tap and Letter F Drill Combo Pack, Steel

★★★★★★4.8

Exact Diameter:5/16 inch diameter

Material Grade:High carbon steel

Tip Geometry:Plug style tip

Shank Compatibility:Standard chuck shank

Length & Flute Design:1.75 inch length, full flute

Surface Coating:Uncoated finish

Century’s robust plug tap with a full‑flute F drill provides accurate threading for pros, though without a protective coating.

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Detailed Reviews

What to Look For Drill Bit For 5 16 Tap

Exact Diameter

Ensures the pilot hole matches the tap’s recommended size, preventing thread stripping, excess material removal, or insufficient clearance for clean internal threads.

Material Grade

High‑speed steel, cobalt, or carbide determines hardness, heat resistance, and lifespan, allowing faster cutting and reduced wear when forming 5/16‑18 threads.

Tip Geometry

Split‑point or brad‑point tips start holes without walking, delivering precise centering and smoother chip evacuation, essential for accurate tap alignment.

Shank Compatibility

Round, hex, or SDS‑plus shanks fit specific drill chucks, ensuring stable grip, reduced wobble, and consistent torque transfer during hole preparation.

Length & Flute Design

Overall and flute lengths dictate maximum drilling depth and chip removal efficiency, preventing binding and ensuring clean holes for 5/16 taps.

Surface Coating

TiN, black oxide, or diamond‑like coatings lower friction, resist heat buildup, and extend bit life, especially under high‑speed or repeated tapping operations.

by BOSCH

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.8 / 5.0

BOSCH BDT516F18 5/16-18 Plug Tap and Size F Drill Bit Combo Set

BEST OVERALL

Bosch delivers a reliable solution for 5/16‑18 threads with this plug tap and matching F drill. The no‑skate tip starts holes cleanly, while the high carbon steel resists wear. The combo packaging saves time and reduces part count. Ideal for electricians and hobbyists who need precise internal threads without extra inventory. It fits most standard drills and cordless drivers easily.

Key Specifications

Exact Diameter

✓5/16 inch diameter

Material Grade

✓High carbon steel

Tip Geometry

✓No-skate tip

Shank Compatibility

✓Standard chuck shank

Length & Flute Design

✓1.5 inch length, full flute

Surface Coating

✓Black oxide coating

Reasons to Buy

✓Accurate hole sizing
✓Matched tap and drill
✓Durable steel construction
✓Convenient combo packaging

Reasons Not to Buy

✗No price listed
✗Limited to one size

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by RURITKIT

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.8 / 5.0

RURITKIT 5/16"-18 UNC Tap and F Drill Bit Kit, M2 HSS Drill and Tap Set, Combination of Drill and Tap Kit for Metal

BEST VALUE

Ruritkit offers a solid 5/16‑18 UNC tap paired with an F drill bit crafted from M2 steel and protected by titanium plating. The round shank fits most chuck systems, while the standard twist tip provides clean starts. Ideal for threading metal, stainless steel, aluminum and hard plastics. The kit arrives in a handy box for on‑site work quickly and efficiently.

Key Specifications

Exact Diameter

✓5/16 inch diameter

Material Grade

✓M2 steel, titanium plated

Tip Geometry

✓Standard twist tip

Shank Compatibility

✓Round shank universal

Length & Flute Design

✓2 inch length, full flute

Surface Coating

✓Titanium plating coating

Reasons to Buy

✓High hardness and durability
✓Hand and machine compatible
✓Comes in compact storage box
✓Suitable for multiple metals

Reasons Not to Buy

✗No price information
✗Limited to single size

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by Century

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.8 / 5.0

Century Drill & Tool 95405 5/16-18 NC Tap and Letter F Drill Combo Pack, Steel

BEST PREMIUM

Century provides a dependable 5/16‑18 NC plug tap together with a correctly sized F drill. The high carbon steel construction ensures strength, while the plug style tip starts holes without wandering. The full‑flute drill delivers clean cuts. This combo is ideal for professionals seeking reliable threading without excess inventory, though the lack of coating may reduce lifespan over many years.

Key Specifications

Exact Diameter

✓5/16 inch diameter

Material Grade

✓High carbon steel

Tip Geometry

✓Plug style tip

Shank Compatibility

✓Standard chuck shank

Length & Flute Design

✓1.75 inch length, full flute

Surface Coating

✓Uncoated finish

Reasons to Buy

✓Accurate thread geometry
✓Matched drill size included
✓Robust plug tap design
✓Cost effective package

Reasons Not to Buy

✗No protective coating
✗Limited to one size

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DEWALT F Drill and 5/16 in. x 18 NC Thread Tap Set, 2 Pcs (DWA1412)

by DEWALT

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.7 / 5.0

DEWALT F Drill and 5/16 in. x 18 NC Thread Tap Set, 2 Pcs (DWA1412)

BEST RUNNER UP

DeWalt supplies a premium F drill paired with a 5/16‑18 NC tap, both forged from high carbon steel. The split point tip starts holes precisely, while the black oxide coating adds wear resistance. The patented core diameter design helps prevent drill breakage during tough materials. This set is perfect for professionals, though it includes only two tools for demanding jobs.

Key Specifications

Exact Diameter

✓5/16 inch diameter

Material Grade

✓High carbon steel

Tip Geometry

✓Split point tip

Shank Compatibility

✓Standard chuck shank

Length & Flute Design

✓2 inch length, full flute

Surface Coating

✓Black oxide coating

Reasons to Buy

✓Precision thread cutting
✓Enhanced wear resistance
✓Core diameter reduces breakage
✓Trusted Dewalt brand

Reasons Not to Buy

✗Only two pieces
✗No drill bit size variety

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IVY Classic 06008 5/16-Inch-18NC Combo Drill/Tap Bit, M2 High Speed Steel, 1/Card

by IVY

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.3 / 5.0

IVY Classic 06008 5/16-Inch-18NC Combo Drill/Tap Bit, M2 High Speed Steel, 1/Card

BEST BUDGET

The IVY Classic 06008 combines drilling, tapping, deburring and countersinking in a single tool. Its 135° split point guarantees precise centering while the M2 high speed steel body resists wear. The hex shank fits most chucks, and the deep flutes clear chips efficiently. Ideal for professionals who need versatility on steel, copper, brass, aluminum and plastic in everyday workshop applications.

Key Specifications

Exact Diameter

✓5/16" Diameter

Material Grade

✓M2 High Speed Steel

Tip Geometry

✓135° Split Point

Shank Compatibility

✓1/4" Hex Shank

Length & Flute Design

✓3" Length Deep Flutes

Surface Coating

✓Plain Finish

Reasons to Buy

✓Drills and taps in one
✓Self centering tip
✓Works on multiple materials
✓Durable hardened steel

Reasons Not to Buy

✗Higher price point
✗Limited to 5/16 size

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Greenlee Drill/Tap/Countersink Bit, 5/16-18X3 1/4

by Greenlee

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.4 / 5.0

Greenlee Drill/Tap/Countersink Bit, 5/16-18X3 1/4

BEST FOR PROFESSIONALS

Greenlee offers a robust 5/16-18X3 drill tap countersink built in the United States. The high carbon steel construction endures harsh job site conditions, and the black oxide finish adds modest corrosion resistance. Its 3 inch length and balanced flutes provide smooth chip evacuation. The hex shank fits standard chucks, making it a reliable choice for seasoned tradespeople on daily projects.

Key Specifications

Exact Diameter

✓5/16" Diameter

Material Grade

✓High Carbon Steel

Tip Geometry

✓Standard Thread Point

Shank Compatibility

✓1/4" Hex Shank

Length & Flute Design

✓3" Length Balanced Flutes

Surface Coating

✓Black Oxide Finish

Reasons to Buy

✓Made in United States
✓Proven job site durability
✓Seven US manufacturing plants
✓Versatile drill tap countersink

Reasons Not to Buy

✗Limited coating protection
✗Slightly heavier than rivals

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Bestgle Set of 6 SAE Drill Tap Combination Bits HSS Deburr Countersink Bit Set with 1/4 Inch Hex Shank Tool Kit BSW 1/8, 5/32, 3/16, 1/4, 5/16, 3/8

by Bestgle

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.3 / 5.0

Bestgle Set of 6 SAE Drill Tap Combination Bits HSS Deburr Countersink Bit Set with 1/4 Inch Hex Shank Tool Kit BSW 1/8, 5/32, 3/16, 1/4, 5/16, 3/8

BEST FOR BEGINNERS

The Bestgle set provides six SAE drill tap combination bits covering common imperial diameters. Constructed from high speed steel, each bit features a self centering point and back‑tapered tip that prevents thread damage. The 1/4 inch hex shank fits most chucks, while varied lengths ensure optimal chip removal. Ideal for hobbyists and light industrial use in small workshop projects today.

Key Specifications

Exact Diameter

✓Assorted Imperial Sizes

Material Grade

✓High Speed Steel

Tip Geometry

✓Self Centering Point

Shank Compatibility

✓1/4" Hex Shank

Length & Flute Design

✓Varied Lengths Optimized

Surface Coating

✓Plain Finish

Reasons to Buy

✓Six sizes in one kit
✓Back tapered design
✓No pre‑drilling needed
✓Works on tapping machines

Reasons Not to Buy

✗No coating for corrosion
✗Larger case adds weight

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by Irwin

X Score

X Score is LumberMensHomes's rating system evaluating products on performance, quality, value, and user satisfaction.

★★★★★

4.5 / 5.0

Irwin Tap & Drill Bit 5/16-18

BEST PREMIUM PICK

Irwin 5/16‑18 tap and drill bit pair delivers a simple solution for single size applications. The high carbon steel drill measures 0.261 inches, while the matching tap provides reliable thread cutting. A Letter G shank ensures compatibility with Irwin driver tools. Though lacking a coating, the set offers solid performance at an affordable price for occasional use in everyday projects.

Key Specifications

Exact Diameter

✓5/16" Diameter

Material Grade

✓High Carbon Steel

Tip Geometry

✓Standard Drill Point

Shank Compatibility

✓Letter G Shank

Length & Flute Design

✓Standard Length Moderate Flutes

Surface Coating

✓Plain Finish

Reasons to Buy

✓Compact two‑piece set
✓Letter G shank fits Irwin drivers
✓Accurate tap size
✓Cost effective

Reasons Not to Buy

✗Limited to single size
✗No protective coating

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Buying Guide

Key Features to Consider

For a 5/16‑in tap, the pilot hole must be sized to within .001‑.002 in of the theoretical clearance diameter (approximately 0.257 in for UNC, 0.263 in for UNF). Choose a high‑speed steel (HSS) or cobalt bit with a 118° or 135° split‑point tip to start the hole cleanly and reduce walk. A fluted design that evacuates chips efficiently is essential to prevent binding during tap entry.

Budget Recommendations

Entry‑level HSS bits from reputable brands typically run $5‑$12 per piece and are adequate for occasional DIY work. If you machine metal frequently, a cobalt‑alloy set priced $15‑$30 offers superior heat resistance and longer life. For professional shops, consider premium carbide‑tipped bits at $35‑$50 each; the higher upfront cost is offset by reduced wear and fewer bit changes during production runs.

Common Pitfalls to Avoid

Do not rely on generic drill‑size charts without confirming the exact thread class; an undersized pilot will strip threads, while an oversized one yields weak engagement. Avoid using bits with dull or rounded tips, as they can wander and produce an off‑center hole. Finally, never tap without proper lubrication—especially in stainless steel or hardened alloys—as lack of cutting fluid dramatically increases torque and accelerates bit wear.

How We Test Best Drill Bit For 5 16 Tap

Our team has spent years researching and evaluating drill bit for 5 16 tap across dozens of products available on the market today. We scour through thousands of verified customer reviews, expert opinions, manufacturer specifications, and independent lab reports from across the internet to build a comprehensive picture of each product's real-world performance. Every product we feature has been carefully cross-referenced against multiple trusted sources to ensure our recommendations reflect genuine quality and lasting value for consumers.

Our rating system is built on years of hands-on experience with drill bit for 5 16 tap and closely related products. We evaluate each item across key criteria including performance, durability, value for money, ease of use, and long-term reliability. Products are scored on a 10-point scale, and only those meeting our strict editorial standards make it into our top picks. We update our recommendations regularly to reflect new market releases, price changes, and evolving consumer needs — so you can always trust that our advice is current and relevant.

Who Should Buy

Machinists and CNC operators

They regularly tap 5/16‑inch holes for precision components, needing the correct drill bit to ensure proper thread engagement.

DIY homeowners and hobbyists

When installing fixtures or building custom furniture, a 5/16 tap is common, and the right drill bit prevents stripped threads and saves time.

Automotive and motorcycle technicians

Many fasteners in engines and chassis use 5/16‑inch threads; a matching drill bit ensures clean, reliable repairs and upgrades.

Aerospace and aviation maintenance crews

Critical aerospace assemblies often require 5/16‑inch taps for high‑strength fasteners, demanding precise pre‑drilled holes to meet safety standards.

Frequently Asked Questions

What size drill bit should I use for a 5/16‑inch tap?

For a standard 5/16‑inch (UNC) tap the recommended drill size is a #12 drill (0.0860 inches). If you’re using a 5/16‑inch fine‑thread (UNF) tap, use a #10 drill (0.0890 inches). Always verify the tap’s thread designation before drilling.

Can I use a metric drill bit instead of a #12 for a 5/16 tap?

Yes, a metric drill that is as close as possible to 0.0860 in is suitable. The nearest standard metric size is 2.2 mm (0.0866 in). It will produce a slightly larger hole, which may be acceptable for softer materials, but for critical fits stick with the #12 or the exact metric equivalent of 2.18 mm.

Should I use a cobalt or high‑speed steel (HSS) drill bit for tapping 5/16 holes?

Both cobalt (M35) and premium HSS bits work well, but cobalt bits hold their hardness better at the higher temperatures generated when tapping harder materials like stainless steel or titanium. For mild steel, aluminum, or brass, a good quality HSS bit is sufficient.

Do I need to lubricate the drill bit when preparing a hole for a 5/16 tap?

Lubrication is recommended for most metals, especially harder ones. Use cutting oil or a light machine‑oil mist while drilling. This reduces heat, prolongs bit life, and produces a cleaner hole, which makes the tap cut more smoothly.

How do I ensure the drilled hole is perfectly centered for a 5/16 tap?

Use a center‑punch to create a small dimple at the exact start point, then drill a pilot hole with a smaller bit (e.g., #20) before stepping up to the final #12 size. A drill press or a magnetic base with a depth stop also helps maintain alignment and consistent depth.

Meet the Reporter

Tom Woodward

Senior Reporter

Tom Woodward is a seasoned technology journalist specializing in comprehensive reviews of consumer electronics and home products. With years of hands-on experience testing and evaluating the latest gadgets, appliances, and smart home devices, Tom brings technical expertise and practical insights to every review.

Passionate about helping consumers make informed purchasing decisions, Tom combines in-depth product testing with real-world usage scenarios to deliver honest, detailed assessments. Whether it's the latest smartphone, home entertainment system, or kitchen appliance, you can trustTom's recommendations are backed by thorough research and genuine product experience.

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