Bolt Size Finder Keychain

Package Contents

• One Bolt Size Finder Keychain

Product Specifications

• Measurements: Metric (8 - 25 mm) and SAE (5/16 - 1") 
• Dimensions: 21cm x 8.5cm x 5cm
• Country of Origin: Taiwan

Features of Our Bolt Size Finder Keychain

Never waste time hunting for the right bolt size again! With its compact, portable design and dual measurement system, this bolt-size gauge keychain gives you instant access to accurate bolt sizes on the go.

• Easy identification: Quickly identify bolt sizes without the hassle of test-fitting sockets.
• Dual measurement system: Handles both metric and SAE bolts, so you get the versatility to tackle any task.
• Compact size: The keychain design is easy to carry, so you’re always ready to find the right size.
• Durable construction: Built to last and backed by a limited lifetime warranty, it’s protected against manufacturer defects.
• Unparalleled customer support: Get answers fast from a real human with a 30-minute customer service response window.
• 90-day return policy: Not satisfied? Return it within 90 days for a full refund, completely risk free.

What Sizes of Bolts Can This Bolt Size Gauge Measure?

This bolt gauge can measure any metric bolt in the 8–25 mm range and any SAE bolt in the 5/16–1 inch range. These charts cover the bolt size range our keychain finder accommodates, for both metric units and SAE ranges.

Bolt Size Finder Keychain Metric Bolt Gauge Chart

Bolt Size Finder Keychain SAE Bolt Gauge Chart

How Do You Use the Olsa Tools Bolt Size Finder?

Use our bolt size finder to measure bolt heads with these easy steps:

1. Move the slider to the bottom of the tool to open it completely.
2. Place the open ends of the tool over the bolt head.
3. Move the slider up the tool until the ends close firmly on the bolt head.
4. The measurement that the slider is closest to is the bolt head size.

How Do I Know What Bolt Size I Need?

When choosing bolts for a project, you need to match the bolt length, diameter, and thread. Here’s how to do it:

• Diameter: Measure the diameter of the hole or threaded opening the bolt will go into. The bolt diameter should match this measurement.
• Length: Measure the thickness of the materials being fastened together, plus any washers and nuts. The bolt should be long enough to fully engage the nut or threaded hole, but not so long that it protrudes excessively.
• Thread pitch: Use a thread gauge to determine the number of threads per inch (for imperial) or the distance between threads (for metric).
• Material thickness: A general rule of thumb is to use a bolt diameter that is 1.5-2.5 times the thickness of the thinner material being fastened.
• Load requirements: Choose thicker and stronger bolts for high torque or heavyweight applications.
• Head style: Choose based on your application needs (hex, socket, etc.)
• Material: Select based on strength requirements and corrosion resistance needed.

To measure an existing bolt:

• Use calipers or a bolt gauge to measure the diameter.
• Measure the length from under the head to the end of the bolt.
• Use a thread pitch gauge to determine the thread count.
• You can also take the old bolt to the hardware store and hold it up next to potential replacements. They should be the same length and diameter. Then, push the working ends of both bolts together and pull slightly. If the threads match, they should interlock.

When in doubt, bring the old bolt or measurements to a hardware store for knowledgeable choices and assistance in finding the right replacement.

Can This Bolt Head Size Finder Fit in My Pocket?

The bolt finder keychain is made for pockets. It’s small, lightweight, and won’t bulk up your jeans or tool belt. Think of it as your go-to sidekick—always there when you need to size up a bolt, but never getting in the way. This compact keychain is ready to tag along and make your next handyman DIY project or job easier.

What Does M10 Mean on a Bolt?

The M10 on a bolt gives you information about its size. The "M" stands for "metric," which indicates that the bolt follows metric bolt measurements. The number "10" refers to the bolt’s diameter in millimeters, so an M10 bolt is 10 mm in diameter.

What Is a Bolt Thread Checker?

A bolt thread checker or thread identifier is a tool used to identify the thread size and type of a bolt or nut. It helps you determine the individual bolts’ thread length, pitch, and whether it's coarse or fine.

How Do I Find the Right Socket Sizes for My Bolts?

Using the wrong socket—either too large or too small—can lead to stripped bolt heads or poor grip, which can damage your tools or slow down your work. To find the right socket for your bolt, match the diameter of the bolt’s head to the appropriate size socket. For example, if you're working with a bolt that has a 10 mm head, you'll need a 10 mm socket for a snug fit. Use our bolt size finder for optimal results every time.

What Are the Dimensions of the Olsa Tools Bolt Size Finder?

The dimensions of our bolt size finder are 21 cm by 8.5 cm by 5 cm.

How Do I Tell What Size a Bolt Head Is?

You can measure the bolt head diameter and compare the measurement to a chart, or you can use our bolt size finder keychain to do it on the go. Just attach the open ends of our bolt head size finder to the bolt head and read the measurement closest to the slider. No matter the types of bolts you prefer, with our tool, you’ll get the perfect bolt for your needs every time.

What Is the Body of a Bolt?

The bolt body is the cylindrical section between its head and endpoint. Depending on the type, the bold body includes a shank and threads. The shank is the smooth, threadless section that comes after the head, and the threads are the working parts of the body that grip the mounting sight or nut.

What Are Fine and Coarse Pitch Threads in a Bolt?

Fine and coarse pitch threads are the spacings between threads on a bolt, which determines their suitability for different applications.

A coarse thread has a wider pitch, so the threads are spaced further apart. This design makes coarse threads faster to install and more resistant to damage or stripping in soft materials. Coarse threads are found in general-purpose applications and offer better grip in materials such as wood or softer metals.

Fine threads have a narrower pitch, with threads spaced closer together. Fine threads provide greater holding strength and are a better choice for precise adjustments or increased tension, such as in automotive or aerospace applications.

In the metric threads system, thread sizes are classified by their diameter and pitch. For example, in metric thread sizes, a bolt might be labeled as M10 x 1.5 for coarse threads (1.5 mm pitch) or M10 x 1.0 for fine threads (1.0 mm pitch). Fine and coarse pitches are standardized, allowing users to select the appropriate thread type for their specific needs.

In the Imperial system, thread sizes are classified by their diameter and threads per inch (TPI). For example, a bolt might be labeled as 1/4"-20 for coarse threads (20 threads per inch) or 1/4"-28 for fine threads (28 threads per inch). The higher TPI in fine threads allows for greater precision and holding strength, while the lower TPI in coarse threads makes them faster to install and more durable in softer materials.

Does Olsa Tools Carry Tool Organizers for Sockets?

Yes, we carry a wide range of socket organizers. Check out our collection of sturdy socket trays, magnetic socket holders, and portable options for DIY enthusiasts and mechanics on the move.

Does Olsa Tools Carry Tool Storage Accessories?

Yes, we do carry toolbox accessories. Our accessories include the bolt size finder keychain, as well as a kneeling pad, a magnetic cup holder that fits standard sizes of cups, mugs, and water bottles, and many other useful accessories any mechanic would want in their arsenal.