Frame boxing question......

[doonjumper]

I've started to box my frame and have read here in the forums that your frame will crack where ever your box ends(if you dont box the entire length of the frame). I would like your opinions on wether or not you think I need to box in front of the SS lines or if you think it will be ok to leave it be. What about the second pic? Thanks

 

[twoslo4five0]

this is a long debate and im wodering it myself.we have a s10 frame sitting here and from the factory its half boxed.you would think gm wouldnt put a frame into production that could crack due to stress.

 

[76zimmer]

My jeepster frame is the same, boxed from the factory from front to the rear kickup. No cracks.

 

[Hogback Fabrication]

this is a long debate and im wodering it myself.we have a s10 frame sitting here and from the factory its half boxed.you would think gm wouldnt put a frame into production that could crack due to stress.

They do tons of engineering and stress tests that none of us will ever do.


However, most of my frame is boxed (not all of it) and I've had no frame cracks at the ends of the boxed sections.

 

[twoslo4five0]

lets see what happens here

http://pirate4x4.com/forum/showthread.php?p=10372765#post10372765

 

[cybrfire]

Don't forget to consider, the factories do their engineering based around a "maximum" amount of stress. How they deteremined what that max was and how it was induced you'd have to ask them.

If you offroad your truck you are going to exceed what they deteremined would be maximum pretty quickly I would guess. So, because they stopped their boxed sections at a given point and it works does not necessarily mean it will work for your application.

Is there a chance you can create a stress riser at the end of a boxed section. You bet! Everytime, probably not. But if you are going to the work of boxing the frame why wouldn't you do the whole thing? Is it worth the risk to skip a spot and then all that work be worth nothing if it did actually crack?

 

[doonjumper]

Don't forget to consider, the factories do their engineering based around a "maximum" amount of stress. How they deteremined what that max was and how it was induced you'd have to ask them.

If you offroad your truck you are going to exceed what they deteremined would be maximum pretty quickly I would guess. So, because they stopped their boxed sections at a given point and it works does not necessarily mean it will work for your application.

Is there a chance you can create a stress riser at the end of a boxed section. You bet! Everytime, probably not. But if you are going to the work of boxing the frame why wouldn't you do the whole thing? Is it worth the risk to skip a spot and then all that work be worth nothing if it did actually crack?

Good point, it shouldnt take me too long to correct it. I can do it in the a.m. while I wait on the UPS dood to delivery me the B-52 hangers I bought from you last week

 

[Fred_M1010]

You will get less of a stress-riser if you make the end something like this:

 

[Greg72]

I was thinking the same thing as Fred.

A gently tapering boxed end instead of a blunt, square end would allow for a better transition from the ultra-stiff boxed section to the unboxed flexible section... sort of like a sway bar or torsion bar effect.

Not sure if the engineering supports this theory or not, but it makes sense in my head.