Structural Anchoring to Walls and Ceiling?

[rossvtaylor]

For structural attachment, I am a fan of welding and rivnuts (or plus nuts) and nuts and bolts. Not necessarily in that order.

I will add that, generally, a 30 mph collision into a solid barrier object would be considered a potentially fatal crash just based on Delta V...the deceleration. So while I appreciate caution and overbuilding, if you're in a collision with something solid at a speed above that, loose objects behind you probably would be the least of your worries. For several reasons, the farther back in the bus you can be the safer you will be in a collision. It just makes it hard to drive from back there. But you should send your significant other to the back of the bus.

[Bus'n it]

Well, I could add a 32" monitor and drive it from the couch via remote control! Ross, you are very correct. If you hit anything like a solid object, you will most likely be done with. Our realistic solid objects are colliding into the back of a Semi trailer. Stay awake people!

[musigenesis]

School bus bodies slide forward on the chassis rails in a head-on collision, though, so the deceleration is less than what you'd get in a completely rigid vehicle.

https://www.youtube.com/watch?v=EJeg...annel=IMMIIMMI

Doesn't seem like it helps the driver much, though, so maybe I will head to the back if I see a tree ahead.

[Bus'n it]

Thats cool! The bus body didn't even flex!

[kidharris]

Originally Posted by Inner Love

I have been working on Inner Love, including myself these last few days and I don’t want this thread to turn into a debate about safety ratios.

O1marc, I haven’t heard of Rivnuts or Nutserts, awesome stuff. With those, even 1/4” looks to be plenty strong.

I’m also curious about how to anchor to the fridge. Is there a way to detect where the refrigerant lines are in the fridge walls for fasteners? Since I’m using a residential fridge, I’m thinking of adhering steel strips to each side with a minimum 2”x4” contact patch (using metal to metal adhesive), fasten it to the studs directly or square tubing, use 1/4” bar stock to spread the load and fasten self tapping metal screws in a grid 1/4” apart. Unless there’s already a product for this.

I suspect that most RV fridges are inside built in cabinets for a reason.


As for refrigerant lines (and electrical) - most new fridges fave the condenser coils inside the cabinets against the outside sheet metal instead of on the outside back of the box like the old units. If the metal feels warm to the touch while the unit is running then there is a coil under the sheet metal. Personally I don't think that I would screw any where on the sides or back of these new units. Just build a solid cabinet around it.

[kidharris]

Originally Posted by musigenesis

School bus bodies slide forward on the chassis rails in a head-on collision, though, so the deceleration is less than what you'd get in a completely rigid vehicle.

Doesn't seem like it helps the driver much, though, so maybe I will head to the back if I see a tree ahead.

Wow, watching the frame "slide" 3 feet out the back was weird. Front door demolished by front wheel and passenger rear wheel demolished the under body, but the same did not happen on the driver side. Wonder why? Appears that the driver side rear wheel must have moved forward with the body,

[flattracker]

I have already installed rivnuts in the "new Crown" to hold some of the verticals (unistrut studs) in place. The rivnuts are mounted through aluminum that is about .040" ? thick. In my case the rivnuts are tasked with holding up against sheer forces and not forces that would pull them down. When you install a rivnut, the material you install them into may be the limiting factor in how much force they will withstand. One could pull a rivnut through the aluminum if placing much weight on them. Another possible problem is that if too much torque is applied to tighten or remove them, they may strip out where they grip the metal and removal or tightening may not work. I have used stainless steel rivnuts in my ceiling so far. The aluminum ceiling is the weaker part of the equation. If you install a rivnut where it passes through a steel rib, you may get a decent amount of strength. Plan in advance where you will use them and use them understanding what direction of force is expected. I also plan to use then to hold down my solar panels on the roof.

[o1marc]

Originally Posted by musigenesis

I'm worried about the rivnuts holding my seat base to its pedestal failing, since I accidentally pulled one out with a screwdriver when I removed my seat temporarily. I assumed the rivnuts were some half-assed post-factory repair, but nope - they make (or made) these buses like that brand-new. Fingers crossed that the forces necessary to fail all eight rivnuts will be enough for the seatbelt to slice me into three pieces anyway.

You and your seat are held in place by the seat belts.

[o1marc]

Originally Posted by kidharris

Wow, watching the frame "slide" 3 feet out the back was weird. Front door demolished by front wheel and passenger rear wheel demolished the under body, but the same did not happen on the driver side. Wonder why? Appears that the driver side rear wheel must have moved forward with the body,

Pretty clear at about :23 that drivers rear wheel is at the rear of the opening after impact.

[BeNimble]

https://www.youtube.com/watch?v=bzs7pmhFoE8

Nuff said?

[kidharris]

Originally Posted by o1marc

Pretty clear at about :23 that drivers rear wheel is at the rear of the opening after impact.

The reason it is "Pretty clear at about :23 that drivers rear wheel is at the rear of the opening after impact" is because the drivers rear wheel moved along with the body when it slid forward, else it would have tore up the bottom sheet metal like the rear wheel on the passenger side did and be sitting 3 feet further back like the rear bumper and both the passenger front and rear wheels. Can't see the drivers front wheel very well.

[o1marc]

I think the motor impact pushed the driveshaft back, twisting the axle so the pass. went rearward and the drivers slightly forward.

[kidharris]

Originally Posted by BeNimble

Nuff said?

What I was refering to is the school bus body sliding forward during the crash as referred to by musigenesis aka MG. This feature is allowed by the clamps that clamp the body to the frame instead of bolting it. Some people don't realize this and start bolting stuff to the frame instead of the body and no telling what is going to happen then. This clamp business was discussed early on in MGs build while he was dealing with the rust he had to make some clamps, someone posted a link where you could buy the clamps.


To see this watch the back bumper in the video (it looks like it suddenly pokes out the back about 3 feet and it looks like the bus instantly grows a rear porch (that was my WOW moment) - optical illusion - the body is moving forward). Other places where it is not quite as obvious is the front passenger wheel totaling the door as the body moves forward and the passenger rear wheel destroying the underbody as the body moves forward. The drivers rear wheel appears to have moved with the body, not sure why.

Ford pickups don't do that

[Mr4btTahoe]

Originally Posted by kidharris

What I was refering to is the school bus body sliding forward during the crash as referred to by musigenesis aka MG. This feature is allowed by the clamps that clamp the body to the frame instead of bolting it. Some people don't realize this and start bolting stuff to the frame instead of the body and no telling what is going to happen then. This clamp business was discussed early on in MGs build while he was dealing with the rust he had to make some clamps, someone posted a link where you could buy the clamps.


To see this watch the back bumper in the video (it looks like it suddenly pokes out the back about 3 feet and it looks like the bus instantly grows a rear porch (that was my WOW moment) - optical illusion - the body is moving forward). Other places where it is not quite as obvious is the front passenger wheel totaling the door as the body moves forward and the passenger rear wheel destroying the underbody as the body moves forward. The drivers rear wheel appears to have moved with the body, not sure why.

Ford pickups don't do that

There's nothing behind the driver's wheel to do damage... the body passes over the tire where on the passenger side, the entryway drops below the center line of the tire. If you watch close, the body moves straight forward and the axle doesn't do anything odd. There's just a lot more in the way of the tire on the passenger side which is the cause for the damage. If it were cut off at floor height instead of dropping down with stairs, the body would pass over the top of the tire just the same on both sides.

[LargeMargeInBaja]

2003, we converted a 1997 Ford CF8000 commercial truck to our concept of an ExpeditionVehicle.
.
I like the interior look of a Gypsy vardo with arched ceiling, so I went to a local-owned lumber salvage yard.
I discovered a massive pile of warped 2x4x12 cedar.
The timbers were routed on four sides for a very nice finish.
The only problem -- probably ninety-percent were warped on multiple planes.
Picture a pretzel.
.
By judiciously sorting, I scrounged seven boards with areas of a mostly-matching arc.
A couple-three quick coats of matte varnish, and it's up ye go.
Instant 'Gypsy vardo'!
.
Our ceiling insulation starts with a thick (but not '2021 thicc' thick [shudders]) adhesive acoustic foam directly on the interior of the roof.
Inside this is one-inch 'pink-board'.
Inside this is rigid two-inch foil-sided expanded poly foam-board.
Staying with the 'simple' theme, this insulation scheme is duplicated on our walls.
.
The two-inch rigid foam-board is self-supporting (bouncing rough logger tracks and trundling across rivers since 2003!).
I mounted it print-side up so the unprinted side faces the interior.
That has nothing to do with nothing other than our intended gentle canvas-duck draping never materialized... because we like our foil 'matte-mirror' ceiling.
.
Our rigid insulation ceiling is self-supporting, so our lovely arched cedar 2x4s are merely decorative.
.
We prefer an 'open' look and feel, so we have no cabinets above waist-level.
Everything mounts to the structural members of the walls with 3/8-inch bolts through to the exterior.
Outside, we use the exposed threaded rod to support awnings and shelves for planters and cooking... but mostly just displaying nice rocks and wood we collect during the stay.
.
Instead of just plain bolts, how about eye-bolts at shoulder-level?
With a 3/8 shank, the 'eye' is about one-inch i.d., so a half-inch o.d. copper pipe fits nicely.
In keeping with our 'rustic' theme, I age the copper using Miracle-Gro© semi-liquid fertilizer.
After a few months on a dry summer roof, I rattle-can some matte clear to stabilize it.
A quick sanding of the 'eyes' to accelerate aging, and the copper slides right in for:
* towel racks
* drapes
* a pseudo 'closet-rod' for clothes-hangers
* but mostly because.
.
.
As I hear about the well-considered plans of new builders with detail blue-prints from nifty-neeto computer programming and months/years of getting ready to prepare to start, a thought often crosses my mind:
* might you be over-thinking this?

[Inner Love]

On a Ford E350 cargo van I had installed 2x4's on the inner walls, by using 2" bronze coated wood screws. I fastened them in a 4x5 grid 1/2" apart for max structural hold on both sides, and wherever the van body contacted the 2x4's I screwed the whole contact patch 1/2" apart. My bed platform was floating on it and it slid 1' forward when I slammed on the brakes once. After that, I screwed it down in 4-6 places with the same wood screws. The 2x4s did not move, then again I never put more than 10G of load on them.

If I used stainless wood-to-metal screws in a similar grid through the s-channels, and interior panels, would it take 30G of sudden pull in a crash? My logic being that it's better to have the load spread out over a 1x24" patch instead of two 1x1 patches (a chain is only as strong as it's weakest link logic).

[Rwnielsen]

Originally Posted by musigenesis

I'm worried about the rivnuts holding my seat base to its pedestal failing, since I accidentally pulled one out with a screwdriver when I removed my seat temporarily. I assumed the rivnuts were some half-assed post-factory repair, but nope - they make (or made) these buses like that brand-new. Fingers crossed that the forces necessary to fail all eight rivnuts will be enough for the seatbelt to slice me into three pieces anyway.

I think think rivnuts would be far more likely to just loosen up and make it difficult to remove the bolts. The way they're deformed during installation, it would take an enormous force to pull them out. I've been dying to buy one of those installation tools but I haven't really had an use for it yet. A few 1/4-20 bolts into overhead ribs should be plenty strong for cabinets. I think the cabinet structure itself would fail leaving the framework in place.
I'm not a structural engineer so this is just my 2 cents

[flattracker]

I used rivnuts to secure vertical lengths of Unistrut in the "new Crown". They are 7/16" coarse thread. In this case the force that the rivnuts need to withstand is a shearing force. If one were to pull down against them it would not be difficult to pull them out of the Crown's aluminum ceiling panels that are about .040" thick. Being that now most of the vertical unistrut is welded to other unistrut pieces, I have no concerns about them pulling out.


I don't think I would use them to hold a driver's set though.


How secure a rivnut is for mounting an object is based on:


1) The material the Rivnut is made of - aluminum, stainless steel, or steel.


2) The material that the Rivnut is installed into - aluminum, steel.


3) How thick the material that the Rivnut is installed into - thicker is better.


A stainless steel 1/2" coarse thread Rivnut installed into steel 1/8" - 1/4" thick would be fairly substantial. The first point of failure would be if over-torqued the Rivnut could turn in its hole.


I will mount my flexible solar panels on the roof of the "new Crown" using stainless steel rivnuts with stainless buttonhead allen screws. Again the resistance will be a shearing force. Sufficient numbers of mounting screws will assure secure mounting of the panels. The Crown's roof is .040" thick aluminum but I believe it will be thick enough.


Since I have a couple squares of the aluminum I removed from the bus to install air conditioners, it might be an interesting test to install some Rivnuts in one and then do a pull test to see what the point of failure is.

[john61ct]

Airline Track, L version low profile.

Rivnuts will hold them fast.

OMNI APPROVED L-Track, Slide ‘N Click and L-Pocket Anchorages can now be used with both Q’STRAINT & SURE-LOK retractors!*"

https://www.qstraint.com/l-track

[Rucker]

Originally Posted by flattracker

I used rivnuts to secure vertical lengths of Unistrut in the "new Crown". They are 7/16" coarse thread. In this case the force that the rivnuts need to withstand is a shearing force. If one were to pull down against them it would not be difficult to pull them out of the Crown's aluminum ceiling panels that are about .040" thick. Being that now most of the vertical unistrut is welded to other unistrut pieces, I have no concerns about them pulling out.


I don't think I would use them to hold a driver's set though.


How secure a rivnut is for mounting an object is based on:


1) The material the Rivnut is made of - aluminum, stainless steel, or steel.


2) The material that the Rivnut is installed into - aluminum, steel.


3) How thick the material that the Rivnut is installed into - thicker is better.


A stainless steel 1/2" coarse thread Rivnut installed into steel 1/8" - 1/4" thick would be fairly substantial. The first point of failure would be if over-torqued the Rivnut could turn in its hole.


I will mount my flexible solar panels on the roof of the "new Crown" using stainless steel rivnuts with stainless buttonhead allen screws. Again the resistance will be a shearing force. Sufficient numbers of mounting screws will assure secure mounting of the panels. The Crown's roof is .040" thick aluminum but I believe it will be thick enough.


Since I have a couple squares of the aluminum I removed from the bus to install air conditioners, it might be an interesting test to install some Rivnuts in one and then do a pull test to see what the point of failure is.

Add some threadlock to those bolts!