Bolts

[jkesselr]

My question stems from a post on the online bolt thread, and is quite simple: are bolts of a certain grade all the same?

Another member mentioned that he buys bolts from an industrial supply house because grade 5 or grade 8 bolts from a farm store (like a TSC) that are sold by the pound are somehow inferior to grade 5 or grade 8 bolts from an industrial supply house.

So, is this ********, or is there something to it? Shouldn’t bolt grades be something standardized and regulated by some gubbermint agency? If there is a difference, what is the difference and how important is it really?

Thanks for playing!

 

[Wamsutta]

If the application is real important like on a car, I either go to NAPA to get Rockford bolts or I go to the salvage yard to get OEM bolts. Hardware store bolts don't come with the flange heads anyway.

 

[kctyphoon]

To my knowledge, they should be the same - and other grades exceeding grade 8 are available.

 

[WittHay]

It's that made in China/Taiwan vs made in USA/Canada thing. Bolt manufacturers put markings on the head of the bolt. The theory is that manufacturers have to register their bolt mark with the government, so the appropriate agency can keep track of quality. The Canadian manufacturers, Paulin/Papco uses a P and Infasco uses a triangle.

I buy Canadian made fasteners because they are readily available and I trust the quality. I am guessing most American diy's use Chinese made bolts, probably doesn't matter where the bolt is made for most at home projects

 

[Mohawk Dave]

I only know grade 8 must be made to spec (read all the same), but F911 bolts are not inspected/made to spec and some are much inferior than others.

IDK about all the others...

 

[Hawke]

Aircraft or real race cars don't use grade 5 or 8 bolts. There are several reasons, and quoted strength is one.

 

[CR888]

Interesting subject, I bet someone really in the know on what's what could write a lengthy post on the issue. I highly doubt ALL bolts in a grade are the same from the multitude of producers. Some minimum standards sure but not exactly equal.

 

[MShaw]

Over the years I have seen counterfeit grad 8 and hex socket bolts. They dump all they can before the authorities step in and shut them down. I would use someone like McMaster Carr that is large enough to have some measure of in house quality control or a local bolt supplier that sells certified hardware to oem customers. I would doubt the quality of box store hardware as they buy by price and probably have no qc.

 

[NUTTSGT]

To my knowledge, they should be the same - and other grades exceeding grade 8 are available.

I'd agree but I'll add keywords . . . . "should be"



I buy most of my bulk bolts at TSC. I started out with the grade 2 stuff and found they had gotten cheaper or atleast it appeared that way. I made the switch to Grades 5 & 8.

 

[Mohawk Dave]

Aircraft or real race cars don't use grade 5 or 8 bolts. There are several reasons, and quoted strength is one.

Gotta disagree with you there, Hoss.

All our Class 7, 8, Trophy Truck, 1610, and Pikes Peak cars, along with all of our competitors, use a ton of grade 8.

....Lots of aerospace 12 point grade 8 as well...

Almost every application in a race vehicle can use grade 8 if the correct size Fastener is used.

 

[bmwpowere36m3]

The bolt grade might be... but what about the thread quality, surface finish, hex tolerances, etc....

Around me, all the hardware store stuff is "cheap" import... I wouldn't trust it in anything critical.

 

[bmwpowere36m3]

Over the years I have seen counterfeit grad 8 and hex socket bolts. They dump all they can before the authorities step in and shut them down. I would use someone like McMaster Carr that is large enough to have some measure of in house quality control or a local bolt supplier that sells certified hardware to oem customers. I would doubt the quality of box store hardware as they buy by price and probably have no qc.

+1

You have to have some trust in the supplier as well... and hardware stores are likely buying on price.

 

[Mohawk Dave]

Years ago it was explained to me...and maybe someone can jump in with the details because I don't fully remember. But it went something like this...

All Grade 8 is made to spec for ISO and ASTM (or something like this), but F911 stuff has no QC that is enforced, and as such, it was not uncommon to get brand new bolts that were bent, wonky, effed up, and would allow plastic deformation easily.

Like I said I don't fully remember the details but I remember the gist of the story and we mainly stick to grade 8. That being said we do by grade 8 from a couple well-known suppliers locally.

 

[2oolhound]

A while back I picked up some bolts from Fastenal. They were ASTM (American Section of the International Association for Testing Materials) A307 Grade A Hot Dipped Galvanized Hex Bolts.

I hadn't seen this standard applied to bolts before. The ISO (International Standards Association) was established by the United Nations after WWII and is more common but there are dozens of international stands organizations in the world. Here is a list on wiki:

International Standards Organizations

With all these available it would be easy for manufacturers to circumvent more commonly recognized standards in order to sell inferior quality.

I find this write up on wiki about the ASTM a little scary:

ASTM

.
.
.

 

[6PTsocket]

As far as TSC goes, selling in bulk is a common practice. I have an industrial supplier near me that sells in bulk and is cheaper than TSC. If you buy a small quantity on line it is how you are buying that is jacking up the cost, not the quality. Go to an industrial sight and see how cheap that stuff is when you buy thousands of pieces. That is how TSC and others can sell in bulk and make money. I have never had problems with grade 5 or grade 8 from any source. I am not servicing an airplane or a racing car and I sure don't think salvaging used OEM stuff from a wreck is preferable to aftermatket new. I have had to replace OEM fasteners so there is nothing to suggest they are any better than what replaces them. The only reason to use them is for a restoration where they take off points if they are not the exact OEM part. Of course this whole discussion is for SAE. Metric strength markings use another system, 8.8, 10.9, etc. The numbers on either side of the decimal are actually two different specs.

Sent from my SM-G900V using Tapatalk

 

[nes999]

There is a difference. We often use grade 8 bolts to pull rod from the ground. When we use TSC bolts they are unusable after 1 or two rods. When we source grade 8 bolts from a local industrial supplier they typically get a day out of a set.

So either TSC has weaker bolts or our local industrial suppliers give us much stronger bolts labeled as grade 8.

Sent from my VS988 using Tapatalk

 

[nbpt100]

You can just look at bolts of the same grade from different sources and see how the plating finishes can be very different. This has more to due with corrosion protection but it speaks to the overall quality, suitability and expected life.

 

[alex71]

Unless counterfeit, asian import grade 5/grade 8 meets the minimum specs for these grades. not just in material, but dimensional tolerances, etc. Domestic product will often exceed the spec. For example lake erie and nucor will use alloy steel for grade 8 instead of medium carbon. pricing isn't that much more, in most cases 20 to 50% higher. Unless you are buying pallets the difference certainly isn't huge.

Other items, such as socket screws are closer in overall quality, because the minimum spec on them is higher for material and tolerances are tighter than hex heads.

 

[seber]

Maybe 30 years or so back we were getting massive bolt failure on our production machines. We started testing the grade 8 bolts and found that we were being supplied with counterfeits. After that we started doing some testing on a regular basis for a while. We found that other than the counterfeits, all grade 8 bolts met the minimum standard. However, some manufacturers went way beyond the minimum. Others barely passed.

 

[alex71]

307A is a low carbon bolt. Think grade 2, 60 KSI tensile. In contrast grade 5 is 120KSI, grade 8 is 150KSI. Grade 9, SHCS, and most 12 points are 170KSI.

A while back I picked up some bolts from Fastenal. They were ASTM (American Section of the International Association for Testing Materials) A307 Grade A Hot Dipped Galvanized Hex Bolts.

I hadn't seen this standard applied to bolts before. The ISO (International Standards Association) was established by the United Nations after WWII and is more common but there are dozens of international stands organizations in the world. Here is a list on wiki:

International Standards Organizations

With all these available it would be easy for manufacturers to circumvent more commonly recognized standards in order to sell inferior quality.

I find this write up on wiki about the ASTM a little scary:

ASTM

.
.
.

 

[vssjim]

If the application is real important like on a car, I either go to NAPA to get Rockford bolts or I go to the salvage yard to get OEM bolts. Hardware store bolts don't come with the flange heads anyway.

I don't think Rockford survived the last reorganization and went under, NAPA may have left overs but now they sell garbage dorman hardware.

 

[alan camby]

you never really know what you are getting from China. Good luck getting traceability documentation. If the seller can't trace the bolt, how do you really know what factory it came from or if they meet any specs? It would be fairly easy for a no name Chinese factory to stamp any manufactures stamp on the head. The big names in the US have traceable numbers on the box. This will get you information like a lot code, date of manufacture, heat treat batch, raw material batch, and lab testing data from the batch/date.
It probably doesn't really matter for most applications though. If you own a company that manufactures crane spreader beams, you might want a traceable product.

 

[alex71]

That may be true for tractor supply bulk bins, but not the case for a real distributor. COO does not affect traceability. For example, the vast majority of our imported heat treated products are from taiwan. We are fully lot controlled, and everything is traceable back not only to the manufacturer, but to the steel mill and raw material lot.

 

[alan camby]

I have seen bad batches of import bolts and they were not from TSC.

I will trust names like Carr-lakeside, Nucor , Lake Erie (LE) over names like
Chan Hsiung, Fang Sheng screw (which is one of the worlds largest).

Both Nucor and LE are made in Indiana.

If my life is on the line, I will choose USA traceable bolts.

From the time the fastener leaves the factory the zinc and black oxide finishes begin to sacrifice to the corrosion gods. Spending 2 to 4 weeks going across the salty ocean does not help the process. Opened many boxes to see they failed to properly oil the BO SHCS's and they have rust all over them.

Like I say, fine for the all the silly little projects around the house and shop, but don't trust your life to it.

do you want Chinese drywall or American?
Chinese dog food or American.

When lifting, do you want Crosby or something that says "China" on the side.

Save the money when you can but don't skimp when a failure will kill you.

With all that said, most failures are a result of improper torque.

 

[alex71]

I was only using TSC as an example. Any merchant that is not lot controlled could be substituted.

And I do not disagree with your assertion, which is why we stock domestic heat treated products. I was simply pointing out that imported does not necessarily mean untraceable.

 

[alan camby]

There are a few fastener items that are almost impossible to find USA COO unless you want to pay absolutely crazy prices. So beware that most of the following will be foreign. If I am wrong, I would like to know the source for reference in future projects.

304/18-8/A2 stainless.
316/A4 Stainless.
nylock style nuts.
Machine screws.
flange bolts.
Spinlock style nuts.

All the above is available if a person wanted to order a huge custom batches for a production plant. Flange bolts are a common item used in production.

 

[alex71]

Domestic stainless is not a problem to get. We offer it as a special order only. It is pretty expensive. Same for machine screw. Flange nuts and flange bolts are for all practical purposes only available as imports. The one exception is infasco grade 8 and 10.9 flange botls which are made in Canada. We do stock those but selection is only so so.

 

[alan camby]

TF has some flange nuts but I have not seen a TF spinlock. maybe it is in their catalog. idk.

Star has stainless but they specialize in aerospace.
Seastrom?
I though Taiwan pretty much owned the stainless market.

I have seen LE flange bolts but not for some time.

I have seen LE bolts that also say Cat. I assume, that at times, LE has made bolts for Cat. I thought most Cat bolts just say Cat.

Fasteners hold the world together, so there are a ton of manufactures.

 

[Joe Mamma]

Based on my experiences, I think a huge percentage of SAE bolts (even grade 5 and 8) I come across are counterfeit. Personally, I just work under the assumption that most SAE bolts I use are counterfeit unless I have some reason to think they aren't.

If I am using SAE bolts and want high quality, I order from some place like McMaster-Carr.

Based on my experiences, it seems like I have a much lower chance of getting counterfeit metric fasteners (as opposed to SAE fasteners). So I tend to use metric fasteners if I want quality without having to buy from someplace special. It's ironic because you would think that most metric fasteners would be cheap counterfeit stuff from China. But that has not been my experience.

Joe Mamma

 

[alex71]

Titan is gone, acquired by lindstrom last year and disassembled. Star is far from an aerospace specialist.

Stsinrlss comes from a variety of countries now. China, Taiwan, India, Singapore... There are a couple of boutique mills making it in the us, in limited sizes and quantities, and pricey.

Lake Erie does not make flange bolts except as specials.

Hth

 

[alan camby]

when I said TF, I was talking head marking.
Telefast industries

 

[alex71]

ahh, OK. I believe they have been acquired by elgin.