is this metric bolt fine or coarse threaded?

[PoorOwner]

Is there a way for you to tell from just looking at it, if this bolt is M8 1.25 pitch or 1.0 pitch?

I think the 1.25 is more common ?


Thanks

 

[tarmy]

Looks course to me...

 

[2ndGearRubber]

That's not 1.00, that's 1.25.

 

[2ndGearRubber]

M8 x 1.00 is basically only found on caliper slide pin bolts. 1.25 is the universal m8 pitch.

 

[matt_i]

All you need is a 6"/300mm scale and you can line up the mm engravings to determine whether they all lineup or not.

 

[f121]

That's corse, 1.25.

Sounds dumb, but fine looks pretty fine. 1.25 is by far most common, 1.0 is used for applications that need higher torque.

 

[BillK]

Looks like 1.25 to me. I just removed 3 broken ones from a cylinder head this morning That is probably one of the most common metric sizes used on engines now days.

 

[MeentSS02]

That also looks like coarse thread to me.

As already stated, if you have something marked out in mm (or have a set of calipers that do metric), measure the peak-to-peak distance of the threads. If it is 8mm x 1.0, the threads will be 1mm apart peak-to-peak. If it is 8mm x 1.25, they'll be 1.25mm apart.

 

[mikegt4]

It looks like the "standard" thread for M8 bolts which is 1.25 mm pitch. It is easy to measure at 4 threads for 5mm of bolt length.

Metric threads don't have "coarse" and "fine", they have a standard thread for each diameter and smaller and larger pitch for more specialized bolts. Sometimes referred to fine, ultra fine, coarse and ultra coarse but normally just the pitch in mm's (0.5, 0.75, 1.00, 1.25 etc.).

 

[PoorOwner]

Thanks a metric lot!!

 

[cvairwerks]

You guys do realize that there are 5 standard pitches for M8 threads?

https://www.engineersedge.com/hardware/metric-external-thread-sizes1.htm

 

[f121]

You guys do realize that there are 5 standard pitches for M8 threads?

Yes. It's a useful education piece though, thanks.

Typically 1.0 and 1.25 are all you see in atuo and general usage, if you are seeing anything below 1.0 then you probably own a thread pitch gauge and have enough experience to reuse the odd bolt with the funny coating and non-typical head size, rather than sticking the 13mm socket on the impact gun and blasting a new thread into it.

 

[MeentSS02]

Typically 1.0 and 1.25 are all you see in atuo and general usage...

This.

 

[Citation]

This isn't hard to figure out. It's a 20mm bolt. On the bottom bolt I can count about 16 threads. That makes it about 1.25 mm/thread.