| Author |
Message |
    
Erik G. Burrows (Erik)
| | Posted on Tuesday, August 13, 2002 - 06:49 pm: | 
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Ok hardware guys, I have a question for you:
Given a 1/8" thick steel plate (like one side of the frame of a Disco), next to a 1/8"+ thick steel plate, joined by a 10mm high-grade bolt, how much shearing force can that join be expected to hold without braking the bolt, or warping the bolt holes?
The question in english is this: How many 10mm bolts joining a disco frame to a winch mount are needed for a 6, 8, 10, or 12k pound winch?
Thanks,
Erik Burrows |
Erik G. Burrows (Erik)
| | Posted on Friday, August 16, 2002 - 02:52 pm: |
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Ok, how about just this: What is the sheer rating of a 13mm, grage 5 or 8 bolt? |
hendrik
| | Posted on Friday, August 16, 2002 - 05:25 pm: |
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BTW there is no place for a grade 4,5,6 bolt in a car. 8.8 is the minimum. I would look for 10.9 bolts (they can be had zinc plated). (instrument panels et.al. can take 4.x grade bolts) |
Erik G. Burrows (Erik)
| | Posted on Friday, August 16, 2002 - 09:09 pm: |
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Hendrik, see the thread called 'Recovery Points'. |
Jeff Price
| | Posted on Friday, August 16, 2002 - 10:57 pm: |
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Hendrik, The grades 5 and 8 Erik refered to is the US (SAE) system fastener grades. You are refering to the metric fastener grades (ISO?) Our 5 (Proof strength 85 kpsi(585 MPa))is equivalent to your 8.8 (Proof 600 MPa) and our 8 (Proof 120 kpsi (826.8 MPa)))is equivalent to your 10.9 (830 MPa).
Erik, the precise geometry of your system and of the application of forces determines the stresses applied. You can calculate the stress a bolt will survive based on the cross section area and the shear strength. In all but the simplest setups that information is only a minor piece of the solution. Determining how the forces and moments act on the fastener is the greater part of the work.
cheers
-jeff |
Ramsay (3toedsloth)
| | Posted on Saturday, August 17, 2002 - 01:56 am: |
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Alright,
All this talk about grades of bolts. I've yet to see any bolts with a grade marked on them. Is it on the head? Do you have to be one with the bolt? Am I blind? What's up?
JR |
hendrik
| | Posted on Saturday, August 17, 2002 - 02:15 am: |
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[D-ohh]
thanks Jeff - foolish me. |
jp
| | Posted on Saturday, August 17, 2002 - 03:44 am: |
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Metric bolts usually have numbers on the head - as above, 8.8 or 10.9 - the numbers may be on the head above two different flats. It can be important that you have the correct grades in order for them to take the recommended torques.
jp |
Kyle
| | Posted on Saturday, August 17, 2002 - 09:03 am: |
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Jeff , that even hurt my head... 
Kyle |
einstein
| | Posted on Saturday, August 17, 2002 - 11:34 am: |
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4 |
Rob Davison (Pokerob)
| | Posted on Saturday, August 17, 2002 - 11:35 am: |
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Erik G. Burrows (Erik)
| | Posted on Saturday, August 17, 2002 - 01:06 pm: |
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Is there a reason why it seems no one knows sheer rating of specific bolts, and why I'm unable to find it on the internet?
Is it some formula that the bolt companies are trying to keep secret? (kidding)
Jeff, you seem to know the strength ratings of various bolts, so you know the sheer ratings? I know overall strength of a system is more than just the attachment point, but for now, that is the part of the system I am trying to figure out. |
Jeff Price
| | Posted on Sunday, August 18, 2002 - 11:58 pm: |
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Erik,
I have the shear ratings for various bolts but not the SAE grades. I have shear ratings for several ASTM bolts and some structural materials. Ultimate shear strength is a fraction of the ultimate tensile strength. It is typically in the 60% range for steel. If you can get the materials data for your fasteners you should be able to compute the shear strength if it is not included. The SAE spec may not specify shear strength.
I think they don't provide that sort of information because most engineers have handbooks, and most everyone else doesn't care. There may be a little bit of "secret recipe" as well as the exact composition may be viewed as a trade secret.
Mostly, they are probably trying to avoid liability. The less information you provide the less you "aided" someone in building a thing that injured someone. Therefor, your liability is limited.
cheers
-jeff |
Ramsay (3toedsloth)
| | Posted on Monday, August 19, 2002 - 01:20 am: |
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Thanks JP and Rob.
JR |
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