Sup bros Car mechanic here Me and another mechanic got into

>>722329126
Not in the slightest, but i'm inclined to agree with him since the weight is still pressing down, its just distributed across a "wider" platform.

>>722329126
The stress is most when the jack is fully extended.

How the hell did this argument start? Stress on the bolts is the same at all degrees.

>>722329405
>>722329649
Hmm....which I believe is 70 degrees

But why?I thought things broke at a 45 degree angle

Since all the weight is on the bolts the entire time all the angle would effect is the angle the force would be put on the bolts. If there is a load on the jack the stress would be the same regardless.

>>722329126
Knock yourselves out

http://www.slideshare.net/MehmetBariskan/final-project-design-and-fem-analysis-of-scissor-jack

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same pressure from above at all times -> same amount of stress the bolts are under at any given point in time.

the angle does nothing at all in this particular scenario.

it is the same on all angles

>>722329774
These things can fail in two ways, shear stress on bolts A B and bending of the top plate

So we were arguing when the bolts were most likely to fail when we're cranking it up

>>722330165
>>722330008
>>722329785
I'm wording this wrong then, maybe I'm asking for angle of maximum shear stress? Like when the bolt would cut in half

>>722329785
Wouldn't there be more force on the bolts because of a moment when at an angle?

I would think the stress with be highest on the pins when the jack is as low as it can be. The effective force up will be the smallest ratio to the total force acting on the bolt in that position.

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Obviously it will be at 100° , 100 is the max limit . At 45-90° that's only 45-90% anything closer to the max 100 endures more stress .

Inb4 what about 110° . No bitch no Jack is ever built past 100

Stay in school faggots

>>722330621

As low as it can be w/o resting on the ground. But yeah I agree.

Don't you ever notice it is easier to jack the thing up as the jack legs straighten out. Or how getting up from a really low squat is a lot tougher than from a half squat etc.

>>722330621
>>722330881
I agree I guess