HF jackstand failure experiment

Holy crap I didn't think it would be that easy.

https://youtu.be/G7_Aa8pbM7Yhttps://youtu.be/G7_Aa8pbM7Y

Basically dude builds an air rig(with maths) to simulate a HF jackstand holding up ~500lbs, and proceeds to encourage the handle to release. You won't do it accidentally, but dang... I thought it would take more than that.

As someone who has just finished 4 days of rocking a 5000lb car back and forth on these same Jack stands on gravel, I don't think I needed to see this.

I'm pretty sure most jack stands will do that if you somehow manage to hit them hard enough. So as a rule, place the stands where you won't hit them with a hammer.

link no work

That's interesting. However, I think a bigger problem if you're flailing away under the car near the jack stands would be just knocking one out from under the car. I've caught myself bracing my foot against one when prying on something before. I think the real message isn't that the stands have a fundamental flaw, it's that you need to be careful when working under a car.

I reposted the link

People criticize the quality of cheapo HF tools, but look at the strength of that failsafe pin!

I dunno. You have to hit them just the right way with a decent amount of force. Not to say that it can't happen, but the odds of it are so remote, I'm not going to spend a lot of time worrying about it.

I'm also not sure about his methodology. The hydraulic press may be able to simulate 500lbs of load or whatever, but look what happens when he releases it. The press stays in place. A car on jackstands isn't going to do that, it's going to keep applying force no matter what happens. Seems to me that would make it harder to knock the lever out of place, every time you hit it, the load of the car will force it back into place, unlike the press which stays in one place.

Tom_Spangler wrote: I'm also not sure about his methodology. The hydraulic press may be able to simulate 500lbs of load or whatever, but look what happens when he releases it. The press stays in place. A car on jackstands isn't going to do that, it's going to keep applying force no matter what happens. Seems to me that would make it harder to knock the lever out of place, every time you hit it, the load of the car will force it back into place, unlike the press which stays in one place.

His rig is applying constant downward force throughout a limited range of motion which is greater than the amount of travel needed to release the jack stand. Open the video in fullscreen and watch the pneumatic piston carefully. As the jackstand releases it goes back to full extension.

In any case, the failsafe pin should've sheared before allowing any 3-digit amount of weight in pounds to be lifted.

So the takeaway is, don't hit the pin on your jackstand with a hammer? I don't think that's a HF issue, that's a how a jackstand works. I bet in the manual of your jackstand it specifically says, "don't hit the pin with a hammer multiple times, while laying underneath your motor vehicle". Or something like that.

Or don't get anything long caught in your jackstand handle in a way that would act as a lever on it, because the failsafe pin will do nothing to save you.

I see no unexpected failure, that's reasonable risk.

If you want safer than that, get the kind with a physical pin through some holes.

So now I know that if I use a hydraulic press with another hydraulic jack converted to pneumatic pressing on a HF jack stand and then pry on the handle with a large pry bar or hit it with a large hammer, the stand will drop.

This is very valuable information that I will use in my professional and personal shop life.

I always thought this story was urban legend. Unreal.

I guess now I'm not that weird for leaving the jack under the car too after letting it settle. Can't be too safe.

The main idea is that the failsafe pin should break before a large amount of pressure is applied to the handle. If the pin should break it would no longer be able to lift up and the locking mechanism would stay in place. I do agree the bigger risk is the dumb things we do like push against them for leverage it use them on gravel but the safety pin should break properly. I'll still use my chinesium off brand stands.

Uh its that what happens when you PRY THE DAMN RELEASE UP!? uhh yeah, I see the pin didn't shear but how about a little common sense....

I have knocked a car on jackstands over but never accidentally collapsed the stand. I agree with the general sentiment that it's possible and some precaution is merited but it's not the low hanging fruit of under-car safety.

Tools don't have a brain, you'll have to use yours.

I am not 100% convinced that pin should have broken.

Its a 6 ton jackstand ... or 12000 lbs. he is using it to lift 500 lbs or ~4% of its intended rating.

What is the minimum force it should take to shear that pin? Probably 500 lbs is too much, but certainly not that far off.

They probably also use the same damn pin size/design on their 2 or 3 ton jackstands though.

I saw that a couple days ago, I think the guy's hypothesis is flawed. If that pin was meant to be a shear pin it wouldn't be a hardened steel roll pin, it'd be something soft, a piece of some sort of wire. He's testing a nonexistent safety.

I'd be more interested to see how much force it takes to push that lever up relative to load, not that it really matters because in my experience the answer is more than one can accidentally apply given any realistic load.

As mentioned, knocking the car off the stands through some combination of poor placement, soft ground (always put a plywood square underneath on non concrete surfaces), and applying lots of force to the chassis though prying and working on large bolts is the real hazard.

He locked a prybar into the handle and put a good deal of force into it. That's not quite the same as I bumped the handle and it failed. So the pin may not have a consistent shear strength. Handles away from the work.

I don't think that's really unexpected. I'd be more interested to know how much pressure was being applied to the release lever with that pry bar.

Was anyone else annoyed that he could figure all that out but used the channel locks backwards when loosening fittings?

Anyone else notice that even after this "failure", the jack stand will still be in place, just at minimum length? That shouldn't be an issue if you're using more than one stand other than the pucker moment. Worst case, you should get stuck but not crushed.