Need Help ID this Nut & Bolt

[Redlands Okie]

It's an M8x1.25 30 mm long bolt. The 8.8 is the grade for metric bolts.

In the land of metric, we don't even bother to mention the pitch (1.25 in this case), only if we actually want a fine thread or something. So we would just call it M8x30 mm bolt.

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Thanks for that post and picture. I had no idea on the tensile strength of the metric 8.8 being so much lower than a grade 8 SAE bolt. Seems the metric is about a grade 3 in SAE. Need a grade 10.9 metric to equal a SAE grade 8.

 

[Redlands Okie]

Hey that's great, thank you. A boat load of grade-5 bolts I can live with. Am I close in assuming the 3F marking is for 3 cm? But what about the F marking?

Keep in mind that according to that chart the metric 8.8 has way less strength than a SAE grade 5. More like a grade 3.

 

[WranglerX]

Keep in mind that according to that chart the metric 8.8 has way less strength than a SAE grade 5. More like a grade 3.

Think you need to go back and read chart some more..... Actually the grade 8.8 metric is a bit stronger than SAE grade 5...

 

[W8BYA]

Thanks. I ended up with a lifetime supply (plus some) so they are what they are. I am glad they are of good quality. Next I need to find a new home for about 500 of them.

 

[Renze]

Howdy group. I came across a very large number of these new nuts & bolts but am not familiar with the stamping on the head. I suspect they are metric as the bolt measures exactly 3 cm in length and a standard 5/16-18 coarse will almost thread on but does not. I read it as 3F on one side then 8.8 across from that. Looks like a heavy Chromate coating for corrosion resistance.
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Interesting... when i get my hands on imperial fasteners, i measure them up in mm, divide that by 25.4 and then try to find how that translates to a fractional dimension...
Then i set my caliper to 25.4mm and count the threads per inch.

When i have metric bolts of a non standard pitch, i count ten windings and measure the mm. Dividing the measurent by 10 andi know the pitch.


To be honest, i dont save imperial bolts: I dont know of any piece of equipment imported to Europe, that uses them so its pointless to save them. AFAIK since the 60s all English produce (Ford, Perkins, IHC) adopted Metric.