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Grade F-911 Bolts


pexter

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With grade 5's having around 105,000 tensile strength and grade 8's having around 160,000, these should be pretty tough at 190,000.

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With grade 5's having around 105,000 tensile strength and grade 8's having around 160,000, these should be pretty tough at 190,000.

I bet :)

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i'm no expert, but i don't think tensile strength has anything to do with how well it bends. The sticks that i have in school to weld with go up to 100k tensile strength and bend easily. I mean coat hanger easy.

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i'm no expert, but i don't think tensile strength has anything to do with how well it bends. The sticks that i have in school to weld with go up to 100k tensile strength and bend easily. I mean coat hanger easy.

How thick are these sticks?

Does anyone know the correct measurement we should be using to figure out how much harder certain bolts are? I usually see tensile strength and shear strength on bolt specifications.

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i'm no expert, but i don't think tensile strength has anything to do with how well it bends. The sticks that i have in school to weld with go up to 100k tensile strength and bend easily. I mean coat hanger easy.

I agree.I think tensile strength is what it takes to pull,or stretch the bolt on both ends at the same time pulling it, till it breaks.

Edited by pexter
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I think it's the "yield strength" that is the measure of the type of bending we do. Pexter is correct about tensil strength being a measure of how hard it is to pull the bolt appart from opposite ends (noone is going to do this!!). And shear strength is breaking the bolt with parallel forces directed in the opposite direction (like ripping paper).

Mike M.

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Allright. Well yield strength for these is 159,000 PSI, and for an average grade 5 is 92,000 and grade 8 is 130,000.

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Jeff - Do you know the yield strength of the 5/16" X 7" G5s that Clay has put a serious (90 deg) bend in?

Mike M.

Edited by supersqueeze
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No, the chart I used only has the minimum strengths for that kind of bolt. It isn't specific to thickness. Here it is for reference

http://www.boltdepot.com/fastener-informat...Grade-Chart.htm

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If I'm not mistaken, these bolts have the same tensile strength, and may very well exceed, most Ivanko barbells. :blink

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So who will be the first to bend a barbell? (braced of course)

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I've kinked one, but there was 350lbs on each end and I was trying to shake it at lockout.

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Mike Dayton claims to have kinked a barbell, but he also claims to have bent US quarters and I find that very hard to believe. The odd part is he claims that breaking handcuffs is his most impressive feat and only mentions that he can bend quarters. I have seen people break handcuffs but we all know the urban legend quality of the quarter bender.

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I don't know about an Elieko bar, but I think a top long bar bender could take down a cheapo bar across the back of the neck. It'd be a pretty expensive way to train though :D

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There has been some discussion here about tensile strengths and how it relates to bending. I think I can add some information that might make things a little clearer when it comes to this topic.

First off, tensile strength and yield strengths are completely different. The tensile strength is indeed the theoretical strength that it would take to pull a piece of the steel apart if you pulled on it like a rope. It is not a force but is given as a pressure (psi-pounds per square inch) So, if you wanted to know the force, you would take the tensile strength (in psi) and multiply that number by the cross-sectional area. So a larger piece of metal (5/16 vs. 1/4) is harder to bend because it has a larger cross-sectional area. Its also why square stock bends easier one way than the other (diamond vs. sqaure)

When you are bending, 2 things happen to the piece at the same time. The outside radius of the bend is put into tension and the inside is put into compression. So the tensile strength does have some bearing as to how difficult a piece is to bend.

Yield strength is usually lower than tensile strength for the same piece of metal. It is the pressure at which a piece moves out of the plastic range and into the yield range. So when you bend, you are exceeding both the yield and tensile strength. If you can only flex the piece of metal and it springs back straight, you have not exceeded the yield strength.

I hope this info helps clarify some of the numbers you see when you look at the information that pertains to a specific bolt or piece of metal. If you have any questions regarding this, let me know and I will try to clarify it even more.

Have fun and keep bending

leonard

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So then, the yield strength is only the pressure needed to cause permanent deformation? So the "work" (if I remember my physics correctly) would be the integral of all the forces over the entire range of the bend and this would be the value of interest? Same with closing a gripper?

Mike M.

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  • 1 year later...
There has been some discussion here about tensile strengths and how it relates to bending. I think I can add some information that might make things a little clearer when it comes to this topic.

First off, tensile strength and yield strengths are completely different. The tensile strength is indeed the theoretical strength that it would take to pull a piece of the steel apart if you pulled on it like a rope. It is not a force but is given as a pressure (psi-pounds per square inch) So, if you wanted to know the force, you would take the tensile strength (in psi) and multiply that number by the cross-sectional area. So a larger piece of metal (5/16 vs. 1/4) is harder to bend because it has a larger cross-sectional area. Its also why square stock bends easier one way than the other (diamond vs. sqaure)

When you are bending, 2 things happen to the piece at the same time. The outside radius of the bend is put into tension and the inside is put into compression. So the tensile strength does have some bearing as to how difficult a piece is to bend.

Yield strength is usually lower than tensile strength for the same piece of metal. It is the pressure at which a piece moves out of the plastic range and into the yield range. So when you bend, you are exceeding both the yield and tensile strength. If you can only flex the piece of metal and it springs back straight, you have not exceeded the yield strength.

I hope this info helps clarify some of the numbers you see when you look at the information that pertains to a specific bolt or piece of metal. If you have any questions regarding this, let me know and I will try to clarify it even more.

Have fun and keep bending

leonard

NOw heres a man who we need to keep on :rock

I am having problems finding accurate info on comparing metric (4.6, 4.8) strengths/grades to US grades (2,5,8etc), can you help me out at all?

Thanls in advance

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Mike Dayton has broke NIJ approved name brand handcuffs with no padding on his wrists. He's also done it using a direct pull. Most people who do that use cheaper foreign made security guard-type handcuffs and they kink the chain and pull that way. Also they use duc tape on their wrists. What I've seen Mike Dayton do is very impressive.

Now as far as the barbell or the quarter, I have no Idea.

I've wanted to try these F-911 bolts. They look pretty cool too.

Tim

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I wonder what the black bolts that Beatty sent to Eric Milfeld and Tmmicklabs and probably a few others are designated. I think they're Grade 12...but wonder if they're similar to these F-911 bolts. Anyone know?

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Ben,

Clay Edgin bent a F911 the 6" x 1/4" it is supposed to be about a grade9. Maybe between a grade 9 and a red.

Greg

Thanks Greg.

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