THe NAC Lots-O-BFG KO2 Thread

Re: THe NAC Lots-O-Post Thread

Dezzzy said:
Lets do math, 7018 welding rod: the "70" stands for 70,000psi tensile strength of the weld if done correctly (obviously we are all pro welders, also dont worry about the 18). estimate the surface area that you have welded on rectangles are LxW, just treaty every surface that the weld covers as a rectangle and add up the surface areas. say you had 4in^2 of surface area. 70,000=F/4, F=70000*4, F=210,000lbs. so if you had a weld that covered 4in^2 it would take 210,000 lbs to break it (straight pulling it). lets say a jeep weighs 3500 lbs, give the weld a safety factor of 12 for shock load 12*3500= 42000lbs so for straight pulling you have a design safety factor of 6. bending is a little different but still due able. not saying you should not do it through the bumper, just a interesting way of looking at it.

commence hating.
Click to expand...

[engineering tip of the day]

Weld strength of a good 70ksi fillet weld:
R = 0.928 x D x L, where D=weld size in 16ths L= weld length -1/2"

You can increase the strength by 50% if the load is applied perpendicular to the weld, but for case i'd only use 40% since the load won't always be perpendicular.

So assuming a 4"x4" plate, you'll have 3.5" of good weld on each side (L = 7" total)
Max. weld size you can use is 1/2 the tab thickness (without reducing), so assuming a 1/2" thick tab, use 1/4" fillet each side. (D = 4)

R = 0.928(4)(7") = 25.98k = 25,984 lb x 140% = 36,377 lb

Impact load safety factor is 2, so take half the allowable load R
R(safe) = 18,189 LB


This doesn't account for base metal thickness or steel strength, but it's a good quick estimate since those rarely control unless you have thin material.

[/engineering tip of the day]
 
Re: THe NAC Lots-O-Post Thread

Dezzzy said:
Lets do math, 7018 welding rod: the "70" stands for 70,000psi tensile strength of the weld if done correctly (obviously we are all pro welders, also dont worry about the 18). estimate the surface area that you have welded on rectangles are LxW, just treaty every surface that the weld covers as a rectangle and add up the surface areas. say you had 4in^2 of surface area. 70,000=F/4, F=70000*4, F=210,000lbs. so if you had a weld that covered 4in^2 it would take 210,000 lbs to break it (straight pulling it). lets say a jeep weighs 3500 lbs, give the weld a safety factor of 12 for shock load 12*3500= 42000lbs so for straight pulling you have a design safety factor of 6. bending is a little different but still due able. not saying you should not do it through the bumper, just a interesting way of looking at it.

commence hating.
Click to expand...

WHAT IS THIS SHIT
 
Re: THe NAC Lots-O-Post Thread

dukie564 said:
[engineering tip of the day]

Weld strength of a good 70ksi fillet weld:
R = 0.928 x D x L, where D=weld size in 16ths L= weld length -1/2"

You can increase the strength by 50% if the load is applied perpendicular to the weld, but for case i'd only use 40% since the load won't always be perpendicular.

So assuming a 4"x4" plate, you'll have 3.5" of good weld on each side (L = 7" total)
Max. weld size you can use is 1/2 the tab thickness (without reducing), so assuming a 1/2" thick tab, use 1/4" fillet each side. (D = 4)

R = 0.928(4)(7") = 25.98k = 25,984 lb x 140% = 36,377 lb

Impact load safety factor is 2, so take half the allowable load R
R(safe) = 18,189 LB


This doesn't account for base metal thickness or steel strength, but it's a good quick estimate since those rarely control unless you have thin material.

[/engineering tip of the day]
Click to expand...
I will have to pull out the formulas for calculating the load on a pull when I get home to add more dumb math to a simple question, but if you go by 18,189 lbs, I can tell you even a 1" shackle is going to fail long before the weld on a side pull.
 
Re: THe NAC Lots-O-Post Thread

nerds.


I've just seen d ring tabs face welded to a 1/4" plate bumper bend the shit out of the 1/4" plate from a side load.
 
Re: THe NAC Lots-O-Post Thread

yea i didn't want to go into that lol. Those equations would make some people's head explode
 
Re: THe NAC Lots-O-Post Thread

you don't need an equation, you just need to not be an idiot lol.
 
Re: THe NAC Lots-O-Post Thread

just had an 04 wj come in with a 2" lift and 20" rockstars.

the kid told me there was a grinding noise coming from the front end. he just picked it up from the used car dealer.

There was NO drivers side axle nut. Brand new axle and unit bearing though. I had one lying around, threw it on for him hoping the bearing wasn't totally ****ed yet. he is lucky the tire didn't fall off on him. The brakes were probably his only saving grace.

He told me about how there was no front driveshaft because he had to get a special one built in California for the 2" lift kit (what the dealer said).

The dealership spray painted everything underneath of course, but failed to spray the unexposed side of the driveshaft.

And he complained that the rearend rides like shit. I bounced on it, looked underneath, and his rear shocks were installed upside down.

What a sketchy-ass used car dealer.
 
Re: THe NAC Lots-O-Post Thread

I have pounders of Schlitz in the fridge. I think I may prefer it over PBR.
 
Re: THe NAC Lots-O-Post Thread

So can't wait to get out of work so I can finish wiring up batterey in the jeep just need cable ends and get a cutting board at target
 
Re: THe NAC Lots-O-Post Thread

LOL I made a brass chariot

13+-+2
 
Re: THe NAC Lots-O-Post Thread

Speaking of gay..

I saw this huge dumb metal thing in a somewhat abandoned building complex today. I thought it was part of a train. when I looked closer I saw it was a hugh lathe. the jaw/chuck part had to be 50" in diameter.

I was going to take a pic but I forgot.
 
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