Here is the reason for drilling a hole through my fuel tank

[paulcjhastings]

Shown is the 1" square tube that is used to drive the outboard slide rails(motor is mounted on the center slide rail). I passes nicely through the fuel tank with very little loss of capacity.

[Sojourner]

Paul...I enjoy seeing the progress report.
My I suggest to add a 1/4 thick cold roll plate with hole smaller than tank's hole. Fasten so that it next to tank's opening of both side and anchored to bus frame. So in case it breaks or whatever to control wobbling shaft from ripping fuel tank. 

Keep up the good work.

FWIW

Sojourn for Christ, Jerry

[paulcjhastings]

The tubing(through the tank) is 3/16" thick, and the risk of the 1" tubing even touching the tank is almost infinitesimal.

[HighTechRedneck]

The tubing(through the tank) is 3/16" thick, and the risk of the 1" tubing even touching the tank is almost infinitesimal.

I understand how unlikely it is, but "almost" is a dangerous word with "Murphy" being so fond of messing with our buses.  I agree with Jerry's suggestion.  Even if you don't use 1/4", something there to safeguard the end of the tank would be easy and cheap insurance.

[paulcjhastings]

Even if the 1" tubing were to break in the middle it cannot move front to back, you guys have me planning for an event that is just not going to happen. To be as safe as you want me to be perhaps we should all put 1/4" plate on our busses for skin. Are you guys afraid to leave your concrete bunker when its raining outside?

[HighTechRedneck]

You are probably right.  Some of us have had too many run-ins with Murphy's Law and are a little on the paranoid side.  If I were in your shoes at this point, I would protect the end of the opening from the admitedly unlikely chance of the shaft breaking right at the opening and gouging into the side of the tank.  But that is the beauty of being a bus nut - we all do it our own way.

[paulcjhastings]

2 points regarding that possibility

Steel doesn't just magically break without deforming first

The tubing is collared to the cog wheel, so if it did break right at that spot it cannot slide into the end of the tank.

[JohnEd]

Paul,

Sit back in a few days and read all of this post   I nearly split a gut.  I could feel you rising to near boil  even if you weren't even close.

I think you idea was genius.  I would never have thought of that and my hats off to you.  Oh, by the way, did you know that it was a tank with a similar hole in it that downed that TWA flight off of Long Island?  The hole in that tank had electric cables running through it that may have shorted and heated the fuel.

It is a great idea and you dotted the I's and crossed the T's.  I intended to install a tank across the entire width of the bus and had pondered cables and such getting past it and now I know how.

Thanks,

John

[Sojourner]

2 points regarding that possibility

Steel doesn't just magically break without deforming first

The tubing is collared to the cog wheel, so if it did break right at that spot it cannot slide into the end of the tank.

Paul...I am sorry to confuse you.

Here my point....if you have a rotating shaft through the tank via welded tubing for tunneling. If that shaft should break or bend or twisted in the tunnel, it can cause it to bind in tunnel & rip or crack welded. The ¼ inch thick safety plate with hole big enough to clear rotating shaft at near both tunnel's opening is to contain wobbling shaft.

It your choice how you choose because it has been shown to other bus nut, it be must aware of the safety factor. It may never be a problem.

FWIW

Sojourn for Christ, Jerry

[Jeremy]

I'd be very interested in understanding the overall layout / design of your slide mechanism - particularly how the slide rails are arranged and designed, and how the 'movement' takes place - ie. rack-and-pinion, screw thread, cables etc? I take it that the bar through the fuel tank is actually a rotating shaft connecting two slide rails together, or perhaps connecting a motor to the rails?

Jeremy

[paulcjhastings]

Jerry,
Have you ever crashed or seen damage to a motorcycle, snowmobile, aircraft with a steel tube fuselage, or car? How many of said vehicles actually have torn parts rather than bent? Steel parts will deform long before they will break. Try bending a piece of thin wall tubing some day. It is a possibility that someone else might drive their bus directly into the side of mine and fracture the weld. That is about what it would take to open up this fuel tank.


Jeremy,
Yes the 1" tube is just a rotating driveshaft, see http://www.barkermfg.com/product_pages/slide_out_systems.html

JohnEd,
It is somewhat exasperating, however, I'll bet when people see it all come together a light bulb will go off, and no further over engineering will be needed.

Some specs on the weakest steel alloy 1018

Ultimate tensile strength 82,000 psi
Yield strength 70,000 psi (substitute this anywhere I used deformed)
Elongation 20% before UTS

[HighTechRedneck]

It is somewhat exasperating,

Sorry that I offended you.  My comments were not intended negatively.

Sincerely,
Mike

[cody]

Paul now I'm scared but in as good way, I have absolutely no knowledge of steel fabrication or tensile strength so I can look at it without any preconcieved notions or opinions and it looks sound, the idea is pure genius and it appears that the only problem would result from a catastropic failure such as a direct hit from the side. It scares me to see something that I know nothing about and find that I understand the concept. lol

[paulcjhastings]

It is somewhat exasperating,

Sorry that I offended you.  My comments were not intended negatively.

Sincerely,
Mike

Not offended, however design suggestions would be better received if the persons commenting knew the total scope of the design.

[junkman42]

Paul, disregard the henny penny's and please continue with the postings.  I really enjoy someone that thinks outside of the box.  Very clever idea and well thought out.  I liked the comment about the bunker,LOL.  Regards , John.