Bolts

[millwight.mike]

I wasn't sure where to post this but here it is. Wondering what crazy stuff other people have seen when it comes to bolts. I asked the helper to bring me some standard bolts. I got a handful of these.

Picture did not do the best job but. Both measure out the same but stamped different.

 

[Tronyadorable]

Grade 8 # 3 ?

http://www.amazon.com/dp/0879384069/?tag=atomicindus08-20

 

[gtlaw]

funny I've seen a lot of defective screws and washers but I never seen a mistake like that.

With the black oxide finish I would bet on the metric grade 8.8 being the correct stamping what size are those 5/16-18 or M8 x 1.25?

 

[BDT/NWMN]

According to my charts,, those bolts should be torqued to 17 foot pounds with a glue gun..

 

[millwight.mike]

3/8 UNC I think that is the one's I took a pic of. The bolt bins are full all sizes like that. They send stock orders out for tender (3 different venders). So we get some interesting things.

 

[BDT/NWMN]

Do those bolts have an industrial or steam fitter application?? Composite lumber??

Some exhaust systems have fasteners with a similar appearance, but those are low grade ....

I have to join the group of curious minds...

 

[millwight.mike]

I work in a truck shop that works on oil well service rigs. They put the bolts on everything. If anything goes overhead we have a small selection of cat blots we use.

 

[BigEd]

Sorry, but I just had to do it.

 

[gtermini]

It looks to me like the bolt on the left is stamped 8.8, which would make it a grade 5 equivalent metric bolt. The one on the right is a grade 8 as others have said.

Greyson

 

[Aerogt01]

Sorry, but I just had to do it.

Saved! Thanks!

 

[millwight.mike]

Snapped a better picture today sorry about that. The bolts are just stamped different. Hex size, threads and bolt sizes all the same.

 

[uart]

The bolts are just stamped different. Hex size, threads and bolt sizes all the same.

Yeah that makes it a lot clearer, gtermini above was spot on. The one on the left is metric grade 8.8 (medium carbon 85000 psi), and the other on is American grade 8 (alloy 120000 psi). Both good strong bolts, but the one on the right is the strongest.

See identifying bolt grades here: http://www.k-tbolt.com/bolt_chart.html

 

[Mohawk Dave]

Snapped a better picture today sorry about that. The bolts are just stamped different. Hex size, threads and bolt sizes all the same.

Yeah that makes it a lot clearer, gtermini above was spot on. The one on the left is metric grade 8.8 (medium carbon 85000 psi), and the other on is American grade 8 (alloy 120000 psi). Both good strong bolts, but the one on the right is the strongest.

See identifying bolt grades here: http://www.k-tbolt.com/bolt_chart.html

Well, they can't have the same threads if one is SAE and one is MM. SO they are either different threads or totally wrong stamping. Right?

The top pic of the threads is blurry...but it does look like they mesh...????

 

[uart]

Well, they can't have the same threads if one is SAE and one is MM. SO they are either different threads or totally wrong stamping. Right?

Arh ok, I finally get the cause for confusion. I'm a bit slow today.

 

[rharman]

Sorry, but I just had to do it.

I want that poster.....

 

[millwight.mike]

They do mesh perfectly when comparing to a tap. They are all standard sizes found the boxes today. They are just all stamped wrong. (china made). I guess some got cheap stock and didn't pass on the savings. I really need that poster for the job site.

 

[Outlawmws]

They do mesh perfectly when comparing to a tap. They are all standard sizes found the boxes today. They are just all stamped wrong. (china made). I guess some got cheap stock and didn't pass on the savings. I really need that poster for the job site.

I just knew that without asking...

This is one thing that scares the hell out of me is the terrible record the chi coms have for counterfeiting fastener grades and providing sub standard fasteners... The aerospace and MIL Spec industries fight this all the time. The don't get it or don't care that it could cost lives... (How many airplanes have now disappeared without a trace? (It ain't ALL Aliens folks!... )

 

[Eds_tls]

The one with the 8.8 marking is a m8 x 1.25 thread. The other is a 5/16-18 thread and its grade 8. Theyre close enough to look similar if you hold them up to a tap

Parts get mixed in heat treat and plating all the time.

 

[ajchien]

The one with the 8.8 marking is a m8 x 1.25 thread. The other is a 5/16-18 thread and its grade 8. Theyre close enough to look similar if you hold them up to a tap

Parts get mixed in heat treat and plating all the time.

I think Ed is right. I can usually thread a 5/16-18 into a m8-1.25 quite a few turns until it starts binding.

 

[Wakefield]

I just knew that without asking...

This is one thing that scares the hell out of me is the terrible record the chi coms have for counterfeiting fastener grades and providing sub standard fasteners... The aerospace and MIL Spec industries fight this all the time. The don't get it or don't care that it could cost lives... (How many airplanes have now disappeared without a trace? (It ain't ALL Aliens folks!... )

The SAE looking bolt appears to have an American manufacturers" identification mark on it-so if it is China then it is counterfeit.

 

[millwight.mike]

This is funny the head size difference between what is stamped sae and metric. 1/2 nut thread on both fine.

 

[csargents1546]

Do you mind if I post that picture?

 

[millwight.mike]

Not at all post all you want.

 

[DenisG]

This is funny the head size difference between what is stamped sae and metric. 1/2 nut thread on both fine.

Those look like 1/2"-13 bolts. For a standard 1/2" diameter hex bolt, the head is 3/4". For a heavy 1/2" diameter hex bolt, the head is 7/8".
https://www.boltdepot.com/fastener-information/Bolts/US-Bolt-Head-Size.aspx
The metric 8.8 material strength designation equates to a Grade 5. Metric 10.9 equals Grade 8 material strength.

 

[millwight.mike]

I have noticed that when using A325 bolts for structural bolt up. I have never saw it grade 8. What my problem is that the bolt is not coated. All the rest of the stock is. It is almost like the thread was recut. I am ok with being wrong that's how most of us learn. Thanks for the input.