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Question About Grades Of Bolts


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#1 OFFLINE   CANCRUSHER

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Posted 27 April 2013 - 03:41 AM

Sorry for the dumb question but can someone tell me the difference between grades of bolts(2,5,8)?

Thanks.



#2 OFFLINE   jchap

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Posted 27 April 2013 - 05:13 AM

The short answer is that Grade 2 is the weakest, Grade 5 is much harder to bend compared to a Grade 2 of the same bolt type, and Grade 8 is even harder to bend than a Grade 5 bolt of the same type.



#3 OFFLINE   CANCRUSHER

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Posted 27 April 2013 - 09:24 AM

The short answer is that Grade 2 is the weakest, Grade 5 is much harder to bend compared to a Grade 2 of the same bolt type, and Grade 8 is even harder to bend than a Grade 5 bolt of the same type.

So a 3/8 grade 2 is equivalent to a 5/16 grade 5?



#4 OFFLINE   jchap

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Posted 27 April 2013 - 09:27 AM

The short answer is that Grade 2 is the weakest, Grade 5 is much harder to bend compared to a Grade 2 of the same bolt type, and Grade 8 is even harder to bend than a Grade 5 bolt of the same type.

So a 3/8 grade 2 is equivalent to a 5/16 grade 5?

Not necessarily.



#5 OFFLINE   Grip_noob

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Posted 27 April 2013 - 05:18 PM

If you look at the minimum requirements to the manufactoring of different grade bolts, a grade 5 is then 41% weaker than a grade 8 and a grade 2 is 61% weaker than a grade 5. Bolts vary, so they can be stronger than this, but not any weaker or the batch would be discarded. Anyway it should give you an idea about the strenght difference between the different grades of bolts.


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#6 ONLINE   Mike Sharkey

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Posted 27 April 2013 - 07:58 PM

Grade 2 Bolts is kind of a catch all for a wide variety of lower quality bolts.  

 

Grade 5, Grade 8, Grade 8.8 Grade 9, etc are all manufactured with much less variation using a higher tolerance with materials for industrial  performance.  (i.e., manufacturers will have tolerance ranges for these bolts).



#7 OFFLINE   CANCRUSHER

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Posted 28 April 2013 - 01:10 AM

Thanks to all for the info.



#8 ONLINE   Jedd Johnson

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Posted 28 April 2013 - 04:45 AM

Cancrusher,

 

I'd also like to throw out there something in case you don't know (I can't tell from what is written already if you know this or not). 

 

You can tell these bolts apart by looking at the heads.  In my experience, Grade 2's have 3 diagonal and parallel slashes on the head.  Grade 5's have 3 dashes around the outside perimeter of the head and the Grade 8 has six around the outside.

 

Hope this helps.  Again, just in case you weren't aware.

 

Jedd


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#9 OFFLINE   Geralt

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Posted 29 April 2013 - 11:45 AM

Now, I'm a complete noob and starter in all of this, but I found (besides Jedd's and this board's excellent links) this one site. 

Gives a good insight also on the gradings. 

 

http://k-tbolt.com/bolt_chart.html

 

I take it that these are universal standards..? 


Edited by Geralt, 29 April 2013 - 11:47 AM.


#10 ONLINE   Mike Sharkey

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Posted 29 April 2013 - 02:30 PM

Listen....

 

Before we get too far down this topic, let me say this.  Bolts.  Bend them, sure.  However, they are not really the optimal pieces of steel to use to work to get better at bending.  Not at all.

 

Think of them as an assistance exercise.  Their movement is weird and springy, and while you can say that makes them harder (which it does) it also makes the forces necessary to destroy them difficult to master, and, more importantly understand.  Think of only learning to bench press with that bamboo bar that Westside uses with weight hanging off them.  Useful, but hardly the ideal primary training tool.

 

Progressive 0-1 Drill Rod is the ideal training stock imo.  Its consistent, bends cleanly but binds up through the bend, leading to strength gains, and has a very difficult crush portion relative to the kink.  Stainless steel is also great, but you can't find the gradated sized you can with 0-1.

 

CRUSHER, I've seen you bend a Red Nail in a single IMP.  The only bolt of 1/4" diameter that might be remotely challenging for you are the black grade 8's that are over 500#.

 

Really you should be looking at Edgins, which are 5/16" Grade 5 bolts.  


Edited by Mike Sharkey, 29 April 2013 - 02:38 PM.

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