Learning, Drilling,

What Size Drill Bit For a 1/4-20 Rivnut?

Are you wondering what size drill bit you need for a 1/4-20 rivnut? I know picking the right drill bit size for this task can feel like a guessing game, but fear not!

Generally, the appropriate drill bit size for a 1/4-20 rivnut drill is between 0.354″ and 0.356.” The size could vary slightly depending on the specific rivnut brand or type you are using. Also, consider factors such as the material you’re drilling into, which could impact the installation process.

I will go into more detail below.

Drill Size for 1/4-20 Rivnut

drill bit drilling through a wood

Let’s first make sure we understand what we’re dealing with. A 1/4-20 Rivnut is a threaded insert that creates strong, secure connections in materials like metal or plastic.

The “1/4” refers to the diameter, and the “20” indicates the thread count per inch (or UNC – Unified National Coarse). Choosing the right drill size is important for a proper fit and easy installation.

Regarding the drill size for a 1/4-20 Rivnut, there is some variation depending on the material used.

The suggested hole size ranges from 0.354″ to 0.356″ for aluminum spline nuts.

But first, let me give you a cool trick: I always test the hole size on a scrap piece of the same material I’m working with to ensure the fit is snug and secure.

It’s essential to keep in mind how crucial the drill bit size is when setting up your project. Select the wrong size, and you could end up with a sloppy fit or even damage to your material.

Review the suggested hole size and test it before jumping in. It’s all about getting the perfect fit, and you’ll be good to go!

Drill Size for 1/4-20 Rivnut Based on Material Type

drill bit set on a drill bit holder

Material TypeSuggested Drill Size for 1/4-20 Rivnut
Aluminum0.354″ – 0.356″
Steel0.375″ – 0.380″
Stainless Steel0.360″ – 0.365″
Plastic0.350″ – 0.355″
Composite Material0.365″ – 0.370″
Other Material (if any)0.370″ – 0.375″

Note: Before using it on your project, test the hole size on a scrap piece of the same material. The drill size can vary based on specific revenue brands, manufacturing tolerances, and project requirements.

Comparison of Common Drill Bit Types

drill bit in different form and sizes

Drill Bit TypeBest Used ForNot Ideal ForSuggested Drill Bit Size for 1/4-20 Rivnut
Twist Drill BitsGeneral Purpose, Variety of MaterialsVery Hard Materials0.354″ – 0.356″
Step Drill BitsSheet Metal, Creating Graduated Hole SizesHard Metals, Precise Drilling0.354″ – 0.356″ (requires precise control)
Masonry Drill BitsConcrete, StoneMetal, WoodNot Applicable
Spade Drill BitsWood, Light MaterialsMetal, Precise DrillingNot Applicable

For “Suggested Drill Bit Size for 1/4-20 Rivnut”, the sizes indicated are the generally recommended sizes for aluminum 1/4-20 rivnuts.

For the “Not Applicable” entries, it suggests that those types of drill bits are generally not suitable for drilling a hole for a 1/4-20 rivnut.

It’s also worth noting that the exact sizes can vary based on the specific material and application, and users should always refer to the rivnut manufacturer’s guidelines or perform practical tests if possible.




  • Machinery’s Handbook by Erik Oberg
  • Audel Machine Shop Basics by Rex Miller


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About Alex Robertson

AvatarCertifications: B.M.E.
Education: University Of Denver - Mechanical Engineering
Lives In: Denver Colorado

Hi, I’m Alex! I’m a co-founder, content strategist, and writer and a close friend of our co-owner, Sam Orlovsky. I received my Bachelor of Mechanical Engineering (B.M.E.) degree from Denver, where we studied together. My passion for technical and creative writing has led me to help Sam with this project.

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