Son of Know Your Bolts

Son of Know Your Bolts

In the comments on yesterday’s piece about Bolt Depot’s poster of fasteners, a reader, JamesB, wrote:

I would encourage budding young fabricators to also take a look at the bolt grade charts and get an inexpensive universal thread gauge. For found fasteners, the grade markings help differentiate metric from SAE, and the thread gauge helps separate the coarse from fine. After you twist the heads off some inexpensive fasteners, the need for the higher grades becomes apparent pretty quick.

Bolt Depot has a decent printable chart (which links to a deeper database) of common bolt grades, sizes and what their head markings look like. Here’s the link to that page:

Bolt Grade Markings and Strength Chart

Know Your Bolts Redux
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6 thoughts on “Son of Know Your Bolts

  1. JamesB says:


  2. Anonymous says:

    For those of us into aircraft, having an AN number reference is also great.

  3. kryptonsson says:

    I’m not a monster but I play one on TV and I ALWAYS use Grade 8 for my neck bolts! Never have to worry about them going soft when I’m charging up for a long weekend of partying no matter HOW much lightening I absorb!! :-D

  4. Wahyuhadihandoyo Tyonugross says:

    get take any hackeds machines registers to me for your ur affiliates clubss

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Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. His free weekly-ish maker tips newsletter can be found at

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