recovery hook
- marakasmalan
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Re: recovery hook
Peter,
Can you perhaps do the calculation and determine the yeald strength of 4.8 4 x 10mm bolts and show us your result. Mine is quite high (even at 40Nm torque applied), and if you have four bolts you must multiply by 4. Now, I would prefer the recovery hook flying rather than the complete rear end of the Patrol.
Remember not to overtighten the bolts, Maybe Peter is the guy to advise what torque to apply, as the applied torque results in stresses in the bolt, reducing both shear and tensile capacity. Fine or coarse pitch thread will also play a small role.
Regards
Can you perhaps do the calculation and determine the yeald strength of 4.8 4 x 10mm bolts and show us your result. Mine is quite high (even at 40Nm torque applied), and if you have four bolts you must multiply by 4. Now, I would prefer the recovery hook flying rather than the complete rear end of the Patrol.
Remember not to overtighten the bolts, Maybe Peter is the guy to advise what torque to apply, as the applied torque results in stresses in the bolt, reducing both shear and tensile capacity. Fine or coarse pitch thread will also play a small role.
Regards
- Peter Connan
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Re: recovery hook
Four M10 Grade 4.8 bolts have a combined yield load of around 7.2 Tons.
This is before any tightening torque has been applied, and as Marnus points out, the tightening load effects how much strength is left for recovery. It is however very difficult to determine the tensile load induced in a bolt due to tightening, because there are a huge number of variables that have a large effect on this, such as the type of lubrication used, the condition of the threads, what washers are used and the surface finish of the mating faces. However the best in my opinion is to use locktite and tighten bolts that are loaded in tension as little as possible. Note that bolts used in shear are a whole different matter, because the shear strength of the hook is affected by the bolt torque...
getting back to the rear hook with it's four M10 bolts, I don't believe 7.2 Tons is enough for snatch recoveries. I believe you need at least grade 8.8 bolts there, because you definately want the rope to be the weakest link in the chain.
And don't be worried about pulling the hook out of the chassis, that's going to take around 30tons of force.
This is before any tightening torque has been applied, and as Marnus points out, the tightening load effects how much strength is left for recovery. It is however very difficult to determine the tensile load induced in a bolt due to tightening, because there are a huge number of variables that have a large effect on this, such as the type of lubrication used, the condition of the threads, what washers are used and the surface finish of the mating faces. However the best in my opinion is to use locktite and tighten bolts that are loaded in tension as little as possible. Note that bolts used in shear are a whole different matter, because the shear strength of the hook is affected by the bolt torque...
getting back to the rear hook with it's four M10 bolts, I don't believe 7.2 Tons is enough for snatch recoveries. I believe you need at least grade 8.8 bolts there, because you definately want the rope to be the weakest link in the chain.
And don't be worried about pulling the hook out of the chassis, that's going to take around 30tons of force.
Mag ons ons kenniskry met lekkerkry aanhoukry.
- jonathan
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Re: recovery hook
Dagse almal
Ek wil graag vir my die recovery punt by die agterste bumper op sit. Ongelukkig het G-Man nie voorraad nie, en is ook nie seker wanneer hy weer sal he nie. Ek kan die Nissan een kry vir so R600, maar ek is nie seker hoe betroubaar hy is nie? Kan ek hom maar koop of het iemand dalk 'n ander voorstel?
Dankie!
Ek wil graag vir my die recovery punt by die agterste bumper op sit. Ongelukkig het G-Man nie voorraad nie, en is ook nie seker wanneer hy weer sal he nie. Ek kan die Nissan een kry vir so R600, maar ek is nie seker hoe betroubaar hy is nie? Kan ek hom maar koop of het iemand dalk 'n ander voorstel?
Dankie!
- SJC
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Re: recovery hook
Ek sien 4x4 direct sin is ook oor die R600.. Hu lyk sterker as nissan sin?
http://www.4x4direct.co.za/recovery-gea ... acket.html
http://www.4x4direct.co.za/recovery-gea ... acket.html
1996 Nissan Patrol 4.2 SGL
- jonathan
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Re: recovery hook
Ek het hom ook gesien, maar die gate line nie op nie as ek reg onthouSJC wrote:Ek sien 4x4 direct sin is ook oor die R600.. Hu lyk sterker as nissan sin?
http://www.4x4direct.co.za/recovery-gea ... acket.html
- iandvl
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Re: recovery hook
Hoor dalk by Tinus. Ek dink hy het 'n paar laat maak. Hulle lyk so:
Ian de Villiers
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- Tinus lotz
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- jonathan
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Re: recovery hook
Mooi man uitstekend! Sal een vat asb. Sal met jou organizeTinus lotz wrote:Ja ek het hulle is 200 elk
- Tinus lotz
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- Jorrie
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Re: recovery hook
Tinus, hou vir my een asb!
Jorrie
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1998 4500 GRX (Benji)
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2011 Jimny Sold (Benji)
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