grade 5 and grade 8 bolts?

[jdemaris]

I've seen some companies use dots instead of lines for their grade markings. Just remember that a grade 8 will have a mark of some kind at every point of the hex head.

It does not always work that way. For example, Deere Co. makes its own hardware and their grade 8 has all the lines coming from a point in the bolt-head center and they radiate out - with none hitting the corners. And, their grade 8 exceeds the usual specs for tensile strength - min. 150,000 PSI tensile strength.
There are several companies that use their own style of grade-marking which I guess gets people confused.
There are also bolts as strong, or stronger with no line markings on the head - e.g. grade 8.1 SAE J429 with 150,000 PSI tensile strength, or ASTM A490 with 170,000 PSI min. tensile strength - but it should have A490 printed on the head. Here's a photo of a Deere Co. grade 8.

 

[beater_k20]

It does not always work that way. For example, Deere Co. makes its own hardware and their grade 8 has all the lines coming from a point in the bolt-head center and they radiate out - with none hitting the corners. And, their grade 8 exceeds the usual specs for tensile strength - min. 150,000 PSI tensile strength.
There are several companies that use their own style of grade-marking which I guess gets people confused.
There are also bolts as strong, or stronger with no line markings on the head - e.g. grade 8.1 SAE J429 with 150,000 PSI tensile strength, or ASTM A490 with 170,000 PSI min. tensile strength - but it should have A490 printed on the head. Here's a photo of a Deere Co. grade 8.

its not just a john deere thing, its covered here too. http://www.engineershandbook.com/Tables/boltgrades.htm

 

[blazin_blazer]

uh to be a mechanical engineer

No, you are wrong. A grade 8 bolt will have a higher shear strength than the same size grade 5 bolt.

Will a grade 5 bend more than a grade 8 when exceeding their shear strength.......sometimes. If you apply "X" amount of shear force to a grade 5 it may very well bend, but apply the same "X" amount of shear force to the grade 8 bolt and nothing happens at all because you have not exceeded the shear strength of the grade 8 bolt. Keep in mind that even if the grade 5 bolt is still holding the pieces together, if it's bent then is has suffered a severe degradation in it's strength and will completely fail soon (assuming the function of the parts it is holding together have not already "failed" because the bent bolt is obviously no longer clamping the pieces together as it did originally).

Will a grade 8 usually break before bending.......probably. But part of that reason is because it requires such a high shear force to make it fail, that the force is simply high enough to shear the bolt........and of course the grade 8 is harder so it will deform less. A grade 5 bolt would of already of completely failed in shear long before reachiing the amount of shear force required to fail the grade 8.

A grade 8 bolt can bend before it breaks....I've had it happen on my truck.

FYI - I'm a mechanical engineer.........

you sure not very good at small details,as if you look at post #14 i already admitted my mistake. now a real engineer wouldn't miss something like that....i'm a analytical tech with a oil company with a physics degree from harding university, and was taught this myth in school, (i play with oil not metal)
my employer was looking for a supplier for all of our fastners and they were using grade 8 and the fastner manufacturer was just trying to get the contract and had a demo set up where the grade 8 snapped b4 the 5 because it became lose got a nick or wear groove and a stress riser occured causing the 8 to snap, whereas the 5 just kept wearing! the bolt manufacturer was trying to convince my employer that they could save money bu buying the 5's. it may have been rigged .i saw the err in my ways and admitted it but it is new evidence that diproves this, but if a stress riser does occur from the bolt loosening it can be a factor and cause a stress riser that will cause the harder bolt to fail 1st... i went to school over 10 yrs ago and i learn new stuff everyday like they taught me light is a constant in school and they recently disproved that, light actually does slow down after it travels so far, and most all our laws of physics are based upon this constant that is not a constant anymore so i will just keep analyzing oil and let you folks rewrite the laws of physics.

 

[roadnotca]

There's also time well spent in reviewing the "ARP" site.

 

[darkshadow]

hey blazin_blazer
a question about that test you saw.

did they use a larger grade 5 and a smaller 8, so there Numbers were the same? to show the hard 8 would shear and the softer5 would bend?




as far as i have ever seen they dont test shear in bolts, they put a nut on the bolt and strech it till it snaps, and check the load, as long as the nubers are ok and the bolt snaped IN the thread it is a pass.


i have cut bolts in a shear, let me tell you the 8's make the thing jump off the floor, when a 5 would he plowed through

 

[randy88k5]

I was going to write about the grade 5 & 8 issue, but I see it has already been addresed. So onto the next oreder of business...

light actually does slow down after it travels so far, and most all our laws of physics are based upon this constant that is not a constant anymore so i will just keep analyzing oil and let you folks rewrite the laws of physics.

Sorry to get off topic, but this really bothers me, and I cant send a PM. Im not really sure where you heard this, but I cant find any evidence to support this claim.

Yes, we can manipulate the speed of light here on earth. This is nothing new. Light bends as it travels throgh different mediums, this has been known for a "few" years now. Same principle as lenses. Light gets focused at a point due to the thicknesses of the lenses (light travels slightly slower due to the varying thickness of the lens). At cold temperatures, they have been able to slow light using certain types of solids and liquids. Light does slow down when it collides with atoms (ie atoms get struck and re-emit photons of differeing wavalengths), this process takes a cartain amount of time. And by tweaking certain properties, we can effectively "slow down light" So, light takes longer to pass through certain media, known as the materials index of refraction. I trust you are not talking about this.

From your prevously stated sentence, you said light slows down the farther it travels, so Im inferring you mean interstellar travel. Different galaxies are said to be red-shifted or blue-shifted, depending on their direction of travel. It is actually the absorbtion and emission characteristics of certain elemets that make this happen (spectroscopy). This does not effectively slow down light. Gravity can bend light (galactic lensing), but not slow it down. This is all answered in the theory of special relativity. So, in the vacuum of space, at near 0 Kelvin, the speed of light is constant. Period.

I have been keping up with the gravitational wave theories, string theory, general relativity debunks, time dialation and such, and still have not heard the prevous statement. Please correct me if Im wrong with scientific research backing it up, and I will concede. Otherwise Im just filing this along with the mythical Blazer.

 

[jdemaris]

Thought experiments

Yes, we can manipulate the speed of light here on earth.
have been keping up with the gravitational wave theories, string theory, general relativity debunks, time dialation and such,.

Manipulate the speed of light in what reference frame - compared to what standard?

Brings us back to Einstien's comments about judging speed while traveling in a moving train.

And - with your coment about Relativity, and/or General Relativity - are you saying much has been debunked - or the alleged debunking has been debunked?

Believe what you want - but very little has been proven beyond a reasonble shadow of doubt - in regard to light travel. Heck - I've yet to see a picture of a photon or a graviton - have you?

I still want to know - when I hop in my spaceship, crack open a beer, and start driving in excess of 190,000 MPH - and it gets dark out - will my headlights still work - or am I outrunning them?

 

[jdemaris]

its not just a john deere thing, its covered here too. http://www.engineershandbook.com/Tables/boltgrades.htm

Yeah - that's why I said "John Deere or example" - the inference was - there are others.

 

[roadnotca]

Manipulate the speed of light in what reference frame - compared to what standard?

Brings us back to Einstien's comments about judging speed while traveling in a moving train.

And - with your coment about Relativity, and/or General Relativity - are you saying much has been debunked - or the alleged debunking has been debunked?

Believe what you want - but very little has been proven beyond a reasonble shadow of doubt - in regard to light travel. Heck - I've yet to see a picture of a photon or a graviton - have you?

I still want to know - when I hop in my spaceship, crack open a beer, and start driving in excess of 190,000 MPH - and it gets dark out - will my headlights still work - or am I outrunning them?

I seen it on TV and movies but yeah, all the stars streak so your headlights, and taillights, should streak too.
O, I forgot, I R a Enginerd 2. (J/K)

 

[randy88k5]

Manipulate the speed of light in what reference frame - compared to what standard?

Here on Earth. It is what we consider an inertial reference frame. Though not inertial in the sense, because we orbit the sun, which has its own orbit in the galaxy, and the galaxy is moving. With all things being equal, a stationary observer on Earth can be considered in an inertial rest frame for such stationary objects on earth (not dealing with quantum mechanics).

And - with your coment about Relativity, and/or General Relativity - are you saying much has been debunked - or the alleged debunking has been debunked?

Not known as of now. Einstein could not sucessfully prove the general relativity. Which is where string theory and gravitational waves come in. The basic premise is gravity does not act instantaneously on another object. The gravity has to travel there some how in order to act upon it, and Einsteins equations do ot allow for such, which was considered, by himself, to be his biggest blunder.

I've yet to see a picture of a photon or a graviton - have you?

That would be hard when one is a disturbance in the E-M field and the other is imaginary.

I still want to know - when I hop in my spaceship, crack open a beer, and start driving in excess of 190,000 MPH - and it gets dark out - will my headlights still work - or am I outrunning them?

Yes. Light travels independent of is originating source. And it is a little over 186,000 miles per second. And that is considering you could go that fast, being time slows down for you and your mass increases, making acceleration more difficult. If time-space could be manipulated ( a curvature in space) and somehow you could "ride" this singularity, relativity would not have an effect on you or your ship.

This is my last post on this subject. I just wanted to poing out some inaccuricies in blazin_blazer's post. Now I am responding to yours. This is getting too off topic. If you want, start a post in the lounge.

 

[Can Can]

Yeah, please take this to the Lounge, brothers. Not only does it belong there, it's been a long time since we've had a discussion of this magnitude. See you on the dark side, lads......

 

[readymix]

I use either grade 2 or aluminium bolts for all of my chevy needs so that they can bend more before they will break....





































































Don't get mad cancan.....I had to do it.

 

[Can Can]

I don't get mad. I get even.

 

[readymix]

Even......






I bet I would loose that war.

 

[loafer]

Bolted joints in shear: Tow hook example

Getting back to bolts again...

It's important to realize that with a properly designed shear joint the bolt(s) do not carry any shear load. The shear loads are transferred through the joint by the friction force between the two mating parts. The friction force is function of the clamping force generated by the bolt; the higher tensile bolt load the higher the friction force between the two parts.

As an example, take the standard aftermarket tow hook that is bolted to the truck with two 1/2-13 grade 8 bolts:

Bolt torque: 100 lb-ft
coefficient of friction between tow hook and frame: approx = 0.74
Axial bolt load due to tightening torque: approx 12,000 lb

Total friction force resisting shear = 18,720lb

So this means that the bolts holding the tow hook on will not see ANY shear load until the force on the hook exceeds approx 18,720lb (in this example anyway).

For safety reasons, the bolts can obviously carry a higher load of approximately 30,000lb (two 1/2-13 grade 8 bolts in shear)

I think this example also illustrates that the two-bolt tow hooks are inadaquate for most of our heavy rigs and are beeter suited for the Jeep guys , especailly when using snatch straps that are rated for 30-60,000lbs!

 

[jdemaris]

Not True

Getting back to bolts again...
It's important to realize that with a properly designed shear joint the bolt(s) do not carry any shear load.

That is not universally true - but boy are we veering of the bolt-grade subject.
Many shear bolts are intended to carry ALL the torsional load - and do not create any useful clamping force. One example are the Grade 2 (or less) shear bolts used in augers in many types of farm equipment, snow-blowers, barn-cleaners,etc.
Another example is my 6' bush hog on my tractor. The cheaper model uses a shear-bolt where the driveshaft hooks to the input shaft of the transmission. No clamping force at all - in fact - the bolt is held in place with a crimped locknut and does not even get tightened to a point where any clamping occurrs. It is very annoying since it breaks easily - but that helps with warranty claims in the manufacutor's behalf. The more expensive model gets an adjustable slip-clutch instead of the shear-bolt.
And - since this is a Chevy or GM forum - how about the shear-shaft that drives the fuel-injection pump in all the 6.2 diesels? It too carries ALL the torsional/rotational load -and is designed to have a weak spot that will snap in two if the pump turns over too hard.

 

[jekbrown]

Getting back to bolts again...

It's important to realize that with a properly designed shear joint the bolt(s) do not carry any shear load. The shear loads are transferred through the joint by the friction force between the two mating parts. The friction force is function of the clamping force generated by the bolt; the higher tensile bolt load the higher the friction force between the two parts.

I may be confused here, but isn't a bolt used to mount, say, a stock front shock on a K5 loaded in shear? The lock nut on the end of the bolt is only at like 20 ft lbs or something... seems like its loaded in shear all the time to me. I dunno.. do engineers call that something else?

j

 

[1979chevystepside]

so wait a minute? You guys are trying to say that bending isnt failure? you guys are CRAZY! Think about it. If you are banking on a bolt bending instead of breaking, thats just insane. Mainly no 2 bolts are exactly alike, meaning they might not all bend. Anyway thats my case, and if your worried about specs, drill it bigger!

 

[blazin_blazer]

light is a constant is a theory just as 2 parallel lines will never intersect(that can't be proven because it is impossible to draw two parallel lines for infinity,therefore it can’t be proven but it is taught as a law)

http://www.abc.net.au/worldtoday/stories/s643460.htm

there is 1 article that shows that e=mc squared is only a theory, if it was a constant it would remain the same no matter what.
even einstein realized this, Einstein went on to discover a more general theory of relativity which explained gravity in terms of curved spacetime, and he talked about the speed of light changing in this new theory. now changing is not constant and constant is constant! even if an outside force is introduced, because constant is constant.

i mean they actually can slow light down to around 38 mph, thats along way from 186,282 mps, therefore its not constant,

does this sound constant, stopping it dead still and then restarting it again with the same speed as before, that sounds like changing to me and changing doesn’t = constant
http://www.hno.harvard.edu/gazette/2001/01.24/01-stoplight.html

now I’m thru with the physics and bolts, I admitted I was wrong about the bolts in post #14!

the bolts as far as I know, were the same diameter, but like I said they were trying to obtain a contract to supply all of our fastners, heck I didn’t get to inspect the bolts, before or after, they were trying to convince the plant manager and other high ranks that they could save money by using a grade 5 on our automated rams, heck they may have cut the 8 in half to cause the failure. I admitted my mistake long ago, but still the flames are smoking.

As far as the mythical blazer goes, it has been documented as 1 of the 1st ten blazer’s ever made, GM even sent me papers showing where it was made and what the * in the vin stands for(*=C.O.P.O.)and the date of manufacture and the order form for the very 1st 10 c.o.p.o blazers were ordered as test vehicles and work mules for gm and they also stated that they were all supposed to have been crushed and the date of sell to a factory worker and alot of other info about c.o.p.o vehicles and it is stripped completely down to the frame and is going thru a full restoration. I can’t wait to go down to my mom and dads place for thanksgiving, as it is in my uncles’ resto shop (about 30 min drive from my parents), and he is restoring it for me own his dime! He is still trying to get me to trade him for my pick of certain vehicles out of his collection. I will post up some pics of it when they get done, showing the hand ebrake and the whole vehicle, I noticed the last time I was down there, when they were 1st starting to strip it, it has a funny instument panel, there aren’t any holes across the bottom, every 1st gen I’ve ever seen had 2 holes on both sides of the column either housing idiot lights or gauges. I am thinking of trading him for the ’90 454 ss and a GTM Supercar kit car from Factory Five Racing. He used a 2003 corvette as the donor car. He says he has about $40,000 in that car alone, and the truck is worth between 30,000-35,000 according to his collectors guide, it has under 100 miles on it, factory plastic still on seat and paper floor mat covers in it. That’s 70,000-75000 he has in the 2 vehicles he said he would trade me for that blazer, do ya,ll think the blazer will be worth that after the restoration? They do 100 point restos, they restored a 1917 something(weird named manufacturer, that I can’t remember) and they had to hand make most of the parts for that car, they have a full machine shop there at their disposal. They can do everything in house, powdercoat, chrome,and cad machines. I may just ask for $100,000 cash and see what he says, cash always seems to sweet’n a deal, I believe I would have no problem with that. Heck he may agree, since we have some paper work from gm about the thing and money is not an issue to him, he has a lease to Isle of Capri because they built their casino on some of his property in Mississippi, right over the bridge from Helena AR, and I do know he set it up where they pay all the people in his immediate family, I think he gets 3% of what they take in, and his grandson who is only 17(still in high school gets like $7000 a week. So $100,000 wouldn’t bother him. I kinda like the blazer tho, but I will want to drive it and it needs to be put in a collection or museum. Once they are thru with it, I’ll make up my mind, cash would be hard to turn down!!

This is my last post in this thread, I admitted my mistake and I’m out.

 

[jekbrown]

ummm.. if you are smart enough to actually understand everything Einstein wrote... how come you can't understand where the above-post belongs (in a different thread, in a different forum!)????? Just a question. Lets stick to bolts and obey moderators...

j