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Boiler's Roof Racks Production Recap Page 9 & Weld Xbar
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Author:  Boiler [ Fri Feb 13, 2009 1:02 am ]
Post subject:  Boiler's Roof Racks Production Recap Page 9 & Weld Xbar

NOTE: Many ideas have been kicked around over the course of this thread. I left it all here in case anyone wanted to go through the whole design phase of our racks. Final offerings can be found in the "recap" post on page 9. Any posts prior to that may or may not be current.

Well I'm currently in the infant stages (research) of developing a new roof rack for my '05 KJ Renegade. Here are my initial design requirements:

- Weight: 25-30 lbs
- Rack Capacity: *300+ lbs distributed
- Mounting: Bolts hold machined, insulated clamps directly attach to roof rails close to plastic ends. Combined with low weight results in easy attachment and removal. Possibly directly to roof mounting points.
- Fabrication material: Aluminum welded by a CWI (AWS certified weld inspector). No rust!
- CNC machined logos / decorative plates integrated into spans between top and bottom side bars. Endless custom possibilities here.
- Professional primer & paint system. Mil-Spec if we have black. Olive Drab Green is the only color I'm positive we do as MIL Standard.

*Capacity note: yeah, I know they say my roof is only 65# but I think that's some CYA bullhockey. I'm just designing it to hold the larger capacity anyway, so the rack could be used on other vehicles. I probably wouldn't exceed 100 lbs on mine, at least to start.

I'd love to get feedback on a few things before I get too far:

1) How important does everyone consider front wind deflectors to be? I have great idea for clean, quiet, anti-vibration attachment, but I'm not sure if its really necessary. I want to put as little extra material on the roof as I have to.

2) Anyone have pictures of their different racks for ideas? I haven't even seen all of the commercially available ones yet, I'm sure. Fabricated ones can lead to great ideas as well.

Author:  jsc7002 [ Fri Feb 13, 2009 1:12 am ]
Post subject: 

I think it would be better to have the wind deflector.
and as far as mounting Im pretty sure they didnt change the bolt spacing any

Author:  tommudd [ Fri Feb 13, 2009 1:41 am ]
Post subject: 

wind deflector helped a lot on my old set up

If I still had my rails etc I would help you out but they are gone!

Author:  Boiler [ Fri Feb 13, 2009 2:52 pm ]
Post subject: 

Here is one idea for a rack. Length and width woud change slightly. I also have not done the attachments yet. Currently at 27 lbs. Also, I don't plan on chrome plating this, but it was the best coloring to get everything to show up.

It could be made with or without the deflector. The attachment method for the deflector should leave it rock solid, anti-vibration, and smooth with no weld dimpling.

I'm tempted to machine BOILER (my usual screen name / college namesake) into the wind deflector, but then again a decal would look about the same. I'm also going to add a plate between the rear two uprights on each side, with a mountain and some text machined out of it. I haven't decided what to put under it yet, maybe "KJ", "Jeep", or "L.O.S.T". I can probably machine the plates for the cost of having someone make me a decal, and it would look fancier....

Image

Author:  JeepinJarhead03 [ Sat Feb 14, 2009 12:17 am ]
Post subject: 

that's gonna look sharp!

when you're done you can make me a bull guard if i'm still trying to find a half decent one at that point :lol:

seriously, i look forward to seeing what you come up with for your rack there

Author:  Boiler [ Mon Feb 16, 2009 3:25 am ]
Post subject: 

Took the factory rails off today. Once I dinged up the first slightly and figured out exactly how they come off, it was easy. Started to realize how tricky the fit between the 4 mounting areas and the roof crown is. Fortunately if there is one thing I do well, its conquer complex geometry.

I know most of you would bolt pads onto the roof and then tack material onto them, but not me! I'm anal enough that I'll have a model of the roof to build around soon. I'm determined to have a solid model of the thing to build from. It is a big part of the fun for me. :)

One nice thing is that you can set a level in the horizontal and get some really symmetric measurements of that cross section. If there was a roof rib in the center, that wouldn't be likely.

Author:  libby [ Mon Feb 16, 2009 4:55 pm ]
Post subject: 

I wish you the best of luck with that roof, there's all kinds of geometry going on there. More than the naked eye sees. You're gonna spend more time and money on the jig than you do a rack. The roof has a radius in both directions so it's like a ball. The real fun starts when you realize that rear is narrower than the front and the radius is not constant. Any straight lines close to the roof line can easily look like a azz.

I not tooting my own horn but, the lower part of my rack is hidden behind the factory rails. Therefore keeping the factory lines. If you want to eliminate the factory rails then I would suggest using a large diameter (1" - 1-1/2") bottom rail and raise it off the roof so that the difference in radii don't visually clash. However, if you have the capability to bend tubing then you're way ahead of me.

Tony

Author:  libby [ Mon Feb 16, 2009 5:15 pm ]
Post subject: 

One more thing.. Add more cross support. You're showing only one aluminum rail. Mine has two 1" sq steel tubes and it still deflects with a load on it. Think about 100 lbs of dead load plus a good bump in the road. I'm not gonna do the math, but that can easily turn into a momentary 300#+ depending on the bump. The first time I really used my rack I put all the heavy stuff in the center. There is almost an inch of clearance between the rack and roof but it was tapping the roof until the weight was redistributed to the sides of the rack.

Although mine is only clamped to the rails and not rigidly mounted so clamps could be twisting around the rail. Anyway, add more structure in the short dimension.

Tony

Author:  Boiler [ Mon Feb 16, 2009 9:43 pm ]
Post subject: 

Thanks for the input. Yeah I'm having "fun" documenting the shape of the roof as we speak. I'm actually tacking together some mounting flats, upright tubes, rails, and a cross member at the highest point just to take it all off and measure it. I'll then do my best to mock up the roof in a model.

One thing I appreciate from your post is that about the dynamic load. I am going to put my final solid model into Ansys to load it and prove that it can handle whatever load I say it can. I'll have to factor in that dynamic loading and I wasn't thinking about it previously. I usually design static loads for what I do.

I am planning on replacing the roof rails and making them part of the rack, so the style rack I showed is probably already out the window...

I've got a little experience with mild complexity in tubing (see chair pic). About 7 years ago I made a solid model of this from an artist rendering, then made bend programs, ram bend fixtures for the large radius bends, and finally welding fixtures. It's going to take me a while to do it all, but its fun and as they say, time is on my side.

Image

Author:  Boiler [ Mon Feb 16, 2009 10:19 pm ]
Post subject: 

Also, some of you wiring guru's might be able to give me some insight. I'm planning on putting light mounting provisions on the rack, as well as holes on the bottom of the cross tube to feed the wiring into. They will all feed over to the drivers side, through a hidden hole in the roof rail which the cross tube will be covering via weld, and then down the roof rail end, through a hole in the mounting bracket and into a hole in the roof.

Is that a bad place to drill the roof for wiring? (ie: between the roof rail bolt holes). I figured I'd use a multi-conductor SOOW type cable to go through a grommet on the roof. Outside the roof (inside the roof rail tube) it would have a quick disconnect on a bit of slack wiring stuffed up into the tube. That would allow removal of the rack if needed. Of course I'd have half a quick disconnect hanging out a hole in my roof if I took the rack off...hmm...

Lastly...Should I just ground each light to the rack? Does paint foul up the grounding points? The wiring is a bit daunting for me, but I'm letting that come later. I just want to make sure I have the correct features to facilitate clean wiring in my rack design.

Author:  jeepmedic46 [ Wed Feb 18, 2009 11:20 am ]
Post subject: 

Boiler wrote:
Here is one idea for a rack. Length and width woud change slightly. I also have not done the attachments yet. Currently at 27 lbs. Also, I don't plan on chrome plating this, but it was the best coloring to get everything to show up.

It could be made with or without the deflector. The attachment method for the deflector should leave it rock solid, anti-vibration, and smooth with no weld dimpling.

I'm tempted to machine BOILER (my usual screen name / college namesake) into the wind deflector, but then again a decal would look about the same. I'm also going to add a plate between the rear two uprights on each side, with a mountain and some text machined out of it. I haven't decided what to put under it yet, maybe "KJ", "Jeep", or "L.O.S.T". I can probably machine the plates for the cost of having someone make me a decal, and it would look fancier....

Image
That is a cool rack.

Author:  ATXKJ [ Wed Feb 18, 2009 11:46 am ]
Post subject: 

The Rennie light bars drill a hole in the roof for wires - they then RTV it and have the plastic cover - seems to work.

so doable - but you've really got to seal it well.

Author:  Boiler [ Sat Feb 28, 2009 1:12 am ]
Post subject: 

Image

Author:  Boiler [ Sat Feb 28, 2009 3:38 am ]
Post subject: 

So I've been making various concepts, here is one I just did in 30 minutes at 2 in the morning. I think I need a "no work after midnight" rule. Thought I'd share anyway just for fun. This is not the same rack as shown in the above post.

Image
Image

Author:  tommudd [ Sat Feb 28, 2009 4:10 am ]
Post subject: 

looks good! :wink:

Author:  sandman [ Sat Feb 28, 2009 10:21 am ]
Post subject: 

That looks great! Personally I don't think I would want a rack with an open front but thats just my own personal taste. Your rack is going to look great.

Author:  Boiler [ Sat Feb 28, 2009 11:00 am ]
Post subject: 

I'm pretty sure I won't be making that last one. Far too much complication with 2 little benefit.

Author:  Boiler [ Sat Feb 28, 2009 3:59 pm ]
Post subject: 

Narrowing it down. What do you like better, #1 has straight side rails with 5" bends & will be made from 1.5" O.D. tube. #2 has fully curved side rails and will be made from 1.3" O.D. pipe. #2 will probably cost about $75 more to make per rack, plus will complicate my welding fixture. If you like #2 better, do you think its worth the cost? Both sizes should be fine for strength and stiffness, though the 1.5 will be that much stiffer. Option #3, not shown, would have the same bend in the front of the side rail as is shown in the back, with straight tube along the top. It would be the easiest to make repeatable as well as add an inch or two to the usable length.

Image

Image

Author:  03CDKJ [ Sat Feb 28, 2009 4:50 pm ]
Post subject: 

#1

Author:  XC204 [ Sat Feb 28, 2009 5:31 pm ]
Post subject: 

The last 2 are pretty good renditions of "libby's" design. So lets crank up the welder and bender and see some hardware.

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