171 replies to this topic

[JHanson]

I agree with you completely.  I wouldn't be replacing those turnbuckles with stronger ones.  Being a half @$$ed engineer, you're just moving the failure point somewhere else like truck bed mount, the bed itself, or the camper.  In a pinch you could use a tiedown strap if you had to if you lost a turnbuckle to get home or to the next hardware store.  After reading this thread, I like my external torklift tie downs better all of the time.

 

A turnbuckle should not break during an emergency lane-change maneuver. There's a difference between a safe failure point and a weak spot. I believe the stock turnbuckles are a weak spot - one of the very very few items I find inadequate on the FWC.

[Captm]

I don't believe you need a "failure point" nor design one in.  Off hand I can't think of anything designed with a failure point intentionally built in.  I knew that I needed to replace the factory turnbuckles but it got pushed to the bottom of the list.  Had I replaced them with a "rated" turnbuckle I don't believed I would have ended up with a couple of thousand dollars worth of damage to the roof my cab.  A "rated" turnbuckle with a Working Load Limit (WLL) will be stamped with it.  Had I been going slower the hooks on the turnbuckle could/would have failed somewhere else on the trail, possibly a non recoverable spot.

Cheers

[ntsqd]

The concept of a "fuse" is appealing, but consider what happens if that "fuse" blows. The camper comes loose in the bed. Is there ever a time when this is acceptable? Standing still is the only time that I can think of, and if the fuse blows there it's "rating" is too low.

[JHa6av8r]

The Hi-lift jack has failure points built into it. A fuse blows because the circuit was overloaded. The canopy of the A-6 and F-14 and most jets is designed to fail in a certain area in case you need to eject through it.

Failure points are designed into systems all the time.

[idahoron]

Shear pins are installed in many pieces of equipment. 

[Captm]

Like I said "off the top of my head".

 

Now doesn't a fuse blows because it was designed to, it fails if it doesn't blow.  Wouldn't the failure of the canopy be if it didn't give under the condition it was designed to?

A shear pin's job by definition is to shear, if it didn't that would be the failure.  Regardless a turnbuckle by design is not meant to fail.  I would be willing to bet that FWC doesn't intend for the turnbuckle to be "fail point" allowing the camper to come free before possibly pulling an anchor point out.

 

Just so I'm aware and operate my Hi-Lift safely what are the failure points built into a Hi-Lift?

 

Cheers

[idahoron]

The shear pin is only designed to "shear" when the load exceeds the working parameters of the intended equipment. I would think that would be the same with a fuse. 

I do agree that I don't think they intended the turnbuckle to be a "shear pin" so to speak. 

[JHa6av8r]

The shear pin is only designed to "shear" when the load exceeds the working parameters of the intended equipment. I would think that would be the same with a fuse. 
I do agree that I don't think they intended the turnbuckle to be a "shear pin" so to speak.

The purpose of a failure point such as a shear pin is to prevent major structural or system damage that is more difficult or costly to repair. If you make your turnbuckles stronger than the camper or truck attachment points, you shift potential failures to them as stated by another poster. It's a matter of design choice where you want a failure to occur. The campers are designed for off-road use within limits. They're not designed to be Baja'd down a washboard dirt road at 50 mph. You can for awhile but at some point something will fail. Choose where you want that failure to be, camper, truck, or turnbuckle.

[idahoron]

I believe we are on the same page. 

[Captm]

I guess you can put me in the no failure point column.  I do not want a failure or weak link in my truck, camper or turnbuckle.    I don't believe that is necessary or desirable.  Which turnbuckle would you use to keep the camper on your truck?

Cheers

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