How to Easily Identify Hex Bolt Steel Grades

Have you ever wondered how to confirm the steel grades you’re looking at no matter where you are? Well we’re happy to report there is an easy way to know for certain items! Many types of metal products use a stamp system so you can determine the quality of material at a glance. This system can apply to metal products ranging from bolts and screws to even jewelry.

Hardware Such as Bolts

There are several different types of stamping systems for hardware to tell you the grade of steel used. When looking at the head of the screw, if you see nothing, the steel used is of low grade. If you see radial lines, these lines indicate the grade of steel the bolt is made from. The number of lines present is two less than the total steel grade. For example, if there are 3 of those radial lines, the steel grade is 5. For lag bolts used for heavier applications that need grade 8 steel, such as our Heavy Duty Floating Shelf bracket, you’ll want to look for bolts with 6 lines. This will help ensure the bolt is strong enough to hold the bracket along with what is on it.

There are other types of stamps for metric grades of steel but in the US, while these are present, they aren’t as common. A chart of most markings can be found here.

Jewelry Grades

If you have gold or silver jewelry in front of you, you can see this type of system at work for yourself. There should be a number on the piece which tells you the quality of material used to make it. For rings this is normally on the inside of it, for necklaces it may be found in an inconspicuous location, either on the back of the piece or near the clasp. Silver typically uses numbers ranging from 925 to 800 which tell you the percentage of silver used in the item, 925 is 92.5% silver. Gold is similar but uses karats, each karat signifies that approximately 4.1% of the material is gold. 24 karats is 100% gold.

The next time you’re at the hardware store, a jewelry showroom, or a flea market, take advantage of this knowledge to confirm exactly what you’re buying!