Roof Raise Frame Cut Offset

[Lee Savoy]

I did a search and couldn't find this discussed, so if this is in the wrong place, moderators, please let me know.

I am gathering all my tools and material for our roof raise. We are keeping the original bus windows and I'm planning on making the frame cuts below the windows. We are planning a 15" roof raise and I'd like to make a 24" wide piece of sheet metal work so that each sheet yields two pieces. Based on my math and Sketchup model, that will only allow me to offset my frame cuts by about 3".

I know a lot of people recommend offsetting the vertical frame cuts so that you don't have a "fault line", but the more I look at it the more my brain says with 15" between the cuts, the offset just doesn't matter. What do you guys think? Is 3" offset for the cuts enough? Is it even required?

I'll be using 1 1/4" square tube in the hat channel with 3/4" 90* angle iron to form my fill in pieces and running the square tube 12 1/2" past the cut top and bottom (1 1/4" x 40" long square tube).

So what do you guys think? Should I come up with a different plan?

[Jolly Roger bus 223]

others will be along soon
i have not myself done a roof raise but i dont see any need in the offset cuts?
what you are adding in is stronger than the ribs that were there previously.
to me the weak points would be at the tops or bottoms of what you add and or burning through the ribs especially near the ends of your additional uprights.

[Lee Savoy]

Originally Posted by Jolly Roger bus 223

to me the weak points would be at the tops or bottoms of what you add and or burning through the ribs especially near the ends of your additional uprights.

That's kind of what I'm thinking. I'm contemplating adding two 1/4" rivets top and bottom of the square tube and keeping the welding on the hat channel down closer to the angle iron on the added square tube.

[Jolly Roger bus 223]

the trick will be the right type of welder.
one to burn into the thicker steel and connect the thinner rib metal without blowing through it at the same time.
do you already know welding or have experienced welders to help?
to be sure there not hard to find in your area?
i grew up on the border of texas and louisiana all the way up and down it working for an oil field consultant. more just a ride along helper when he needed it

[rossvtaylor]

I agree...and I think I even mentioned this in another thread recently...but I've slept since then, so who knows. It's "common practice" to stagger the cuts, but where did that come from? The "fault line" theory doesn't make sense to me, with proper welds and structure as you intend to do. The biggest real concern, I think, might be a line of distorted welds or weld beads that "telegraph" through the skin and show a bump. But, properly welded, that should not be a weak spot. And with your planned tube inserts you should be stronger than factory.

Of course, if your welds don't penetrate or are porous or just suck, then...never mind.

[Lee Savoy]

Originally Posted by Jolly Roger bus 223

do you already know welding or have experienced welders to help?

I do know how to weld, I learned stick welding as a kid then worked as a boilermaker/pipe fitter for the first few years after high school. I learned to weld most everything around the refineries I worked in. It seems that I've managed to find one or two welding projects every year since then. It's amazing the things that show up at your door when your buddies know you have a welder and can use it. The one thing I haven't done is spot weld body panels, I've got to practice that a bit before welding in the transition panels. My dad can also weld, so I'm going to enlist his help too.

Originally Posted by rossvtaylor

The "fault line" theory doesn't make sense to me, with proper welds and structure as you intend to do. The biggest real concern, I think, might be a line of distorted welds or weld beads that "telegraph" through the skin and show a bump. But, properly welded, that should not be a weak spot. And with your planned tube inserts you should be stronger than factory.

Of course, if your welds don't penetrate or are porous or just suck, then...never mind.

I feel the same way. Once you cut that frame and move it apart, my mind can't see how it matters. I'm not an engineer, but....

Hopefully I've brushed up enough that my welds don't just suck.

[Lee Savoy]

Just a quick update, after looking everything over again this past weekend, we've decided to ditch the original windows and use RV windows. It won't look exactly the way we want it to, but it won't be like living in a basket either. After pulling a bunch of the original windows and trying to make them seal and stay closed we just decided it's more work and expense to finagle something together than just sheet the whole raise area and cut in RV windows. I'm still going to do the replacement uprights the same way then will cut/modify the framing once I have the new windows in hand.

[s2mikon]

And if you raise it to high it is quick to lower it. https://youtu.be/USu8vT_tfdw

[Lee Savoy]

Originally Posted by s2mikon

And if you raise it to high it is quick to lower it. https://youtu.be/USu8vT_tfdw

That's exactly why when my wife said she wanted a 24" roof raise I said NO! If my math is correct we should be just below 11' all said and done. Roof rack and solar will add another foot. I'll be paying close attention to headroom signs for sure.

[s2mikon]

Was it the where the 55 and the 20 came together there was a low train crossing with a truck bypass?

[Lee Savoy]

Originally Posted by s2mikon

Was it the where the 55 and the 20 came together there was a low train crossing with a truck bypass?

That video is from Jackson?

[s2mikon]

201 Gregson St in Durham, NC

[s2mikon]

I seem to remember one on I-20 at the I-55 interchange or am I forgetting.

[s2mikon]

Tears them up doesn't it. People just don't read the signs.

[Lee Savoy]

Originally Posted by s2mikon

Tears them up doesn't it. People just don't read the signs.

Right! I'm going to put a reminder in a couple of places on the dash about my exact height once we finish the bus to hopefully help me pay attention to things like that.

[Lee Savoy]

Originally Posted by s2mikon

I seem to remember one on I-20 at the I-55 interchange or am I forgetting.

Man, it's been a minute since I've been though Jackson on the interstate, I don't remember either. The last couple of times, I was on the Natchez Trace on my motorcycle.

[cntryby]

Originally Posted by Lee Savoy

I did a search and couldn't find this discussed, so if this is in the wrong place, moderators, please let me know.

I am gathering all my tools and material for our roof raise. We are keeping the original bus windows and I'm planning on making the frame cuts below the windows. We are planning a 15" roof raise and I'd like to make a 24" wide piece of sheet metal work so that each sheet yields two pieces. Based on my math and Sketchup model, that will only allow me to offset my frame cuts by about 3".

I know a lot of people recommend offsetting the vertical frame cuts so that you don't have a "fault line", but the more I look at it the more my brain says with 15" between the cuts, the offset just doesn't matter. What do you guys think? Is 3" offset for the cuts enough? Is it even required?

I'll be using 1 1/4" square tube in the hat channel with 3/4" 90* angle iron to form my fill in pieces and running the square tube 12 1/2" past the cut top and bottom (1 1/4" x 40" long square tube).

So what do you guys think? Should I come up with a different plan?

The offset doesn't concern me as much as the loss of the interior sheet metal. Having the interior metal close in each section between all the ribs, creating a box makes the walls much stronger.

I think I am going to try and use the thin tubing from the seat frames to put gussets between all the ribs, essentially creating a truss. (if they're long enough)

Possibly even add a six or 8 inch strip of sheet metal on the inside, directly below the window. Similar to the factory strip along the bottom.

[GWRider]

Originally Posted by Lee Savoy

Right! I'm going to put a reminder in a couple of places on the dash about my exact height once we finish the bus to hopefully help me pay attention to things like that.

There is a RR bridge just like the one in the video just down the street from us that is around 11'6. We have witnessed Trucks get stuck under that Bridge. We did a 16" raise on our Crown and avoid going down that street. We plan to use an app like TruckBook, TruckMap, Waze etc. to avoid low Bridges.

[musigenesis]

Originally Posted by GWRider

There is a RR bridge just like the one in the video just down the street from us that is around 11'6. We have witnessed Trucks get stuck under that Bridge. We did a 16" raise on our Crown and avoid going down that street. We plan to use an app like TruckBook, TruckMap, Waze etc. to avoid low Bridges.

Just yesterday I was about to take a right turn down a road I never go on for some variety in my drive back to my parking spot, but noticed a sign that said "no trucks above 10' 8". I'm at 10' 3" but I didn't feel like having that particular cheek-clenching experience right then (especially because I've only eyeballed the height of my new Maxxair vent fan). A lot of the roads around where I live date to the late 1600s and early 1700s and apparently they didn't have Youtube back then to shame the stonemasons into making their bridge arches bigger.

[GWRider]

Originally Posted by musigenesis

Just yesterday I was about to take a right turn down a road I never go on for some variety in my drive back to my parking spot, but noticed a sign that said "no trucks above 10' 8". I'm at 10' 3" but I didn't feel like having that particular cheek-clenching experience right then (especially because I've only eyeballed the height of my new Maxxair vent fan). A lot of the roads around where I live date to the late 1600s and early 1700s and apparently they didn't have Youtube back then to shame the stonemasons into making their bridge arches bigger.

It appears there needs to be more of these