# What does the 8 8 mean on a metric bolt?

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## What does 8.8 mean on metric bolts?

The grade 8.8 refers to the tensile strength which is generally 116,000 psi, grade 10.9 is generally 150,000 and grade 12.9 is generally 175,000 psi.

## What do the numbers on metric bolts mean?

The common class (grades) for metric are 5.8, 8.8, 10.9 and 12.9. Each grade has a specific bolt strength. No matter the system used to grade the bolts, the higher number means the stronger the bolt.

## What is the difference between 8.8 and 10.9 bolts?

Class 10.9 is stronger than class 8.8. It is commonly found in high strength automotive applications. Class 10.9 is similar to grade 8.

## What does Grade 8 mean for a bolt?

Grade 8 – Grade 8 bolts are made from medium carbon alloy steel. The bolts of this grade feature 6 radial lines. The nominal size of the grade 8 bolts can be from 1/4″ to 1 1/2″. The minimum yield strength of this grade bolt is 130,000 psi.

## How hard is a Grade 8 bolt?

A grade 8 bolt is the highest grade SAE bolt. Grade 8 bolts have a minimum tensile strength of 150,000 PSI.

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## Is M8 8mm?

The defined diameter of metric bolts is actually slightly larger than the actual diameter of the bolt shaft. So an M8 bolt would have a shaft diameter that’s slightly under 8mm which means that the bolt should fit through an 8mm hole.

## Will a 8mm bolt fit a 5 16?

Can I use a M8 bolt on a 5/16 thread? They look pretty similar at glance… Well, quick answer is no. They are not the same and they are not interchangeable, although they can work under certain circumstances.

## How do you identify metric threads?

Metric threads are measured by their pitch. That is the distance from the crest of one thread to the crest of the next measured in millimetres. The pitch of a metric thread can be checked by direct measurement with a metric rule. Imperial threads have their pitch measured indirectly as a given number of teeth per inch.

## Is Grade 8 or 12.9 stronger?

Table 1.

Metric Class 12.9 The highest metric class for strength, it exceeds Grade 8.

## How strong is a metric 8.8 Bolt?

Metric steel bolts, screws and studs – proof and tensile strength

Property Class Size Range (mm) Minimum Tensile Strength (106 Pa)
5.8 M5 – M24 520
8.8 M1.6 – M36 830
9.8 M1.6 – M16 900
10.9 M5 – M36 1040

## Are M10 and 3/8 the same?

That said, they are very close, the 3/8″ bolt is about 0.019″ smaller and the pitch’s are very close so the 3/8 -16 bolt will thread in the 10mm x 1.5 but the 10 x 1.5 bolt will not fit the 3/8 but..

## What does M14 mean on a bolt?

M14 means it is metric with a 14mm outside diameter.

## Is M10 the same as 10mm?

If the size is M10 x 25, that would mean that the diameter is 10 mm. … The 25 indicated a length of 25 mm. A matching nut would be labeled M10, which also doesn’t require a thread pitch since it’s a course thread fastener.