Difference Between Metric and Imperial Bolts | OFS
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What Is the Difference Between Metric and Imperial Bolts?

It happens all the time. You start working on a home or car repair project, and you need a bolt. No problem, you think, as you walk to your trusty coffee can full of nuts, bolts, and screws. You grab an imperial fastener and head back to your task believing that your metric wrench can handle securing it. You will be sorely disappointed as these two types of fasteners cannot swap out easily.

Avoid getting left without the right type of bolt when you understand the differences between imperial and metric grades. Basically, they break down as such:

  • Metric:
    • As the name suggests, a metric bolt is a measure using the metric system even if they are made in the United States.
    • They are sized in millimeters.
    • Their tensile strength (or how strong it is) is found by looking at the markings on the bolt head.
  • Imperial (or Standard):
    • You can find them in inches or fractions of inches.
    • There are two basic types – fine thread and coarse thread.
    • The strength is found by checking the markings on the head of the bolt. For instance, 3 dashes indicates Grade 5, while 6 dashes indicates Grade 8.

Finding the right bolt, screw, or nail for your project starts with a chat with the knowledgeable staff at Ottawa Fastener Supply. We have hundreds of options and the know-how to help you decide your best options. Additionally, we have great lines of tools to ensure your fasteners are secured properly. Go ahead and give us a call with all your questions. We can handle it!

Due to worldwide shortage of N95 masks, hand sanitizer, sanitizing wipes, and other PPE (Personal Protective Equipment), Ottawa Fastener cannot promise delivery ETA’s for these products and will NOT be holding products for customers. If products do become available, it will be on a first come, first served basis. Please call 613 828 5311 or email sales@ottawafastenersupply.com if you are looking for these products.

Thank you.