Rack Wanted Critique Please

[AndySpill]

A few days ago you can find my post ("Rack Wanted") where I described a pipe dream (pun intended) of a rack that connected (only) to the body of the JL with (bendable) pipe, with no rain gutter connection such that it would work with any (or no) top, where the horizontal members of the rack above, connected to the pipe would be composed of light weight and incredibly strong aluminum extrusion.

Aluminum extrusion, as those of you familiar with it know, isn't by design easily bendable, but its linear sections makes for a great material to work with for the portion of the rack that lies above the vehicle top, given this sections near rectangular shape.

People have done great things with this stuff interfacing with their vehicle top: something I was to avoid e.g.:



I was hoping people could critique my design. It starts with a diagram in which you'll pardon my artwork (attached AluminumExtrusionRoofRack.pdf)

The vertical member pipe is connected to the aluminum extrusion at the point of the "X" marks via stanchion hardware I found in the 8020 catalog (those who work with aluminum extrusion know of 8020) on its current page 7-5 at https://catalogs.8020.net/80-20-Catalog-24/7-5/
or attached below at Page7-5of8020catalog.pdf, using hardware that looks like this, that clamps around the pipe and provides a platform upon which to connect aluminum extrusion

Given the weight load on this hardware, I might put a collar below such hardware on straight sections of the pipe (attached Straight_Coupling_Spec.pdf) from Steel-Tek (available at Lowes) that looks like this:

Thoughts? Thanks.

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[Ratbert]

Do you do any off-roading in tight trees where it's quite possible that you'll touch a tree with your rack? Yes, it happens more than I'd like to admit and I'm wondering how well the aluminum would deal with those impacts.

 

[GATORB8]

What are you planning on loading? I think you'll likely want to bear the 8020 on the pipe and do a bolted connection.

 

[Remorseless]

Well, this thread went a different direction than I was hoping. Maybe someone will resurrect this title during beach season with, umm, different content.

 

[AndySpill]

Do you do any off-roading in tight trees where it's quite possible that you'll touch a tree with your rack? Yes, it happens more than I'd like to admit and I'm wondering how well the aluminum would deal with those impacts.

I don't. But I don't follow where you're going with this line of reasoning John. Would you mind further explanation?

Are you perhaps concerned that the lack of flexibility of the aluminum extrusion might force/transfer pressure on the vertical members, for example?

 

[AndySpill]

What are you planning on loading? I think you'll likely want to bear the 8020 on the pipe and do a bolted connection.

Matt, are you saying--I'm confused--that the aluminum extrusion being held up by a grip on the outer diameter of the vertical pipe is your concern and that by bolting through the pipe I would then have the force of that bolt in shear (or the pipe, whichever is weaker,) rather the merely friction of contact made with the outer diameter of the pipe by the stanchion hardware I featured?

 

[GATORB8]

Matt, are you saying--I'm confused--that the aluminum extrusion being held up by a grip on the outer diameter of the vertical pipe is your concern and that by bolting through the pipe I would then have the force of that bolt in shear (or the pipe, whichever is weaker,) rather the merely friction of contact made with the outer diameter of the pipe by the stanchion hardware I featured?

I'm assuming the vertical load is critical force. Bearing/laying the 8020 on the horizontal section of pipe would minimize the amount of force on the connection. The bolt would just be there for lateral (shear) and uplift (tension), presumably the smaller of the forces.

 

[AndySpill]

Such a thread would be "Rack Critique Wanted Please," not as here "Rack Wanted Critique Please."

I based this opinion on the simple reality that those in search of the rack you envision, on a "Racks, Carriers, and Cargo Hauling" forum no less, it would stand to reason, do not turn down such opportunity when presented to them, simply based on said item's questionable attributes, as my title's NSFW double entendre would imply, "throwing away bread to look for crumbs."

Perhaps though if "Carriers" are some synonym for supportive undergarments in the forum's title you might have a point though.

I believe and fear that I have just steered my thread permanently away from Wrangler methods of carrying gear above the vehicle's top.

 

[AndySpill]

I'm assuming the vertical load is critical force. Bearing/laying the 8020 on the horizontal section of pipe would minimize the amount of force on the connection. The bolt would just be there for lateral (shear) and uplift (tension), presumably the smaller of the forces.

I'm assuming the vertical load is critical force. Bearing/laying the 8020 on the horizontal section of pipe would minimize the amount of force on the connection. The bolt would just be there for lateral (shear) and uplift (tension), presumably the smaller of the forces.

Got it.

That's an excellent point. Perhaps the stanchion on page 7-7 https://catalogs.8020.net/80-20-Catalog-24/7-7/ is more "my ticket."

You know, I took the route I originally did because I wanted the rack wider than the top, to facilitate taking a soft top off as long as the rack was absent cross members when not in use.

But since I control the pipe's shape I could make it curve horizontal while still over the vehicle, wider than its top.


Thanks.


BTW : @Remorseless , I can only assume that this design direction change, making the rack wider than the top, is one you'd whole heartedly endorse, for engineering reasons of course.

 

[Remorseless]

Got it.

That's an excellent point. Perhaps the stanchion on page 7-7 https://catalogs.8020.net/80-20-Catalog-24/7-7/ is more "my ticket."

You know, I took the route I originally did because I wanted the rack wider than the top, to facilitate taking a soft top off as long as the rack was absent cross members when not in use.

But since I control the pipe's shape I could make it curve horizontal while still over the vehicle, wider than its top.


Thanks.


BTW : @Remorseless , I can only assume that this design direction change, making the rack wider than the top, is one you'd whole heartedly endorse, fpor engineering reasons of course.

Big racks good, yes

 

[AndySpill]

Big racks good, yes

That's from Shakespeare, correct?

 

[Remorseless]

That's from Shakespeare, correct?

Socratitties

 

[GATORB8]

Got it.

That's an excellent point. Perhaps the stanchion on page 7-7 https://catalogs.8020.net/80-20-Catalog-24/7-7/ is more "my ticket."

You know, I took the route I originally did because I wanted the rack wider than the top, to facilitate taking a soft top off as long as the rack was absent cross members when not in use.

But since I control the pipe's shape I could make it curve horizontal while still over the vehicle, wider than its top.


Thanks.


BTW : @Remorseless , I can only assume that this design direction change, making the rack wider than the top, is one you'd whole heartedly endorse, for engineering reasons of course.

What are you trying to carry?

 

[AndySpill]

Thanks everyone; goodnight. @Remorseless and I will be here all week. Make sure to tip your waiters.

No @Remorseless, "tip" was not misspelled. It's not the word your thinking of.

 

[AndySpill]

What are you trying to carry?

Moving the kid's apartment stuff.....Big box store crap...not tents

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