121 reviews

Bolt Size Finder Keychain

$12.87
Part: 1753

Bolt Size Finder Keychain

Part: 1753 121 reviews
$12.87
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  • Easily identify bolt sizes on-the-go.
  • Small and compact size makes it easy to carry around anywhere.
  • Effortlessly switch between Metric and SAE measurements
  • Say goodbye to the days of test fitting sockets to find the right size.
Default Title

Bolt Size Finder Keychain

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Instant Bolt

Size Identification

Our Bolt Size Finder gauge lets you identify any bolt or nut size instantly, saving you time and effort.No more testing different sockets to find the right size—our tool makes the process simple and easy.

Measures Both

Metric and SAE Bolts

Our Bolt Size Finder measures both Metric (8 - 25 mm) and SAE (5/16 - 1") bolts, making it versatile and suitable for any job.With this tool, you won't have to worry about grabbing the wrong socket.

Portable and

Compact Keychain

Our Bolt Size Finder is portable and compact, making it easy to take with you on the go.Attach it to your keychain and you'll always have it on-hand when you need it.

Saves You

Time and Effort

Our Bolt Size Finder saves you time and effort by allowing you to quickly and easily identify bolt and nut sizes.No more wasted time trying to figure out which socket to use our tool does the work for you.

Why Buy From Us

Unrivaled Service

Talk to a real human for customer support within 30 business minutes or get your money back.

Limited Lifetime Warranty

All hand tools and tool organizers include a limited lifetime warranty that covers all manufacturer's defects.

90-Day Returns

Use our tools completely risk-free for 90 days and if you're not happy with them, get a full refund.

Satisfaction Guaranteed

We go above and beyond to to make your buying experience as easy & smooth as possible.

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 (mm) Ratchet size (mm)
M5 8
M6 10
M8 13
M10 16
M12 18
M14 21
M16 24
M18 27
M20 30
M22 32
M24 36
M25 38

Bolt Size Finder Keychain SAE Bolt Gauge Chart

Bolt size (in) Ratchet size (in)
5/16 1/2
3/8 9/16
7/16 5/8
1/2 3/4
9/16 13/16
5/8 15/16
3/4 1-1/8
7/8 1-5/16
1 1-1/2

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.

Customer Reviews
4.5 Based on 121 Reviews
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Filter Reviews:
MR
12/13/2024
Mike R.
United States United States

Absolutely a time saver

I wish I had this the last 35 years! To the life of me I have to grab 10 wrenches and Sockets to find the fit and it's always next to the last tool you grab! I don't know why I can't determine size by eye. I get so mad when my buddies can do it. It works like a charm! Thank you

Olsa Tools Bolt Size Finder Keychain Review
JW
11/17/2024
Justin W.
United States United States

Handy measurement tool!

Great tool to measure the size of bolts and nuts before grabbing a wrench!

11/18/2024

Olsa Tools

Hello Justin, Thank you for taking the time to write positive feedback for us. We highly appreciate it. Warm Regards, Olsa Tools

RE
11/09/2024
Robert E.
United States United States

Quick and easy

What a time saver. I don't need to grab a hand full of sockets and take them to my car. I can find all the sizes I need and then grab the sockets I need.. I love this thing..

11/15/2024

Olsa Tools

Hello Robert, Thanks so much for sharing your experience and writing positive feedback for us. We hope to see you again soon. Warm Regards, Olsa Tools

J
11/05/2024
Jorge SVG verified by SHOP
United States United States

I like it on point with measurement.

11/05/2024

Olsa Tools

Hello Jorge, Thank you for taking the time to write positive feedback for us. We highly appreciate it. Warm Regards, Olsa Tools

RB
10/30/2024
rgbraun1 B.
United States United States

Fantastic

Fantastic and easy tool to use. Great time saver.

10/31/2024

Olsa Tools

Hello Braun, Thanks so much for sharing your experience and writing positive feedback for us. We hope to see you again soon. Warm Regards, Olsa Tools