Calculating beam size for a trailer.

[MrBeast]

I am designing a goose neck trailer, it is going to have a 36 foot deck and an 8 foot neck.

I want to make the trailer durable, it will have a tandem dual setup, but at the same time I don't want to make it too heavy.

Does anyone know the formula for determining the strength of an I-beam?

[Fegenbush]

I am thinking that you are going to want more of a design than just the main beams. My recommendation is to hire an engineer to come up with some sizes and maybe drawings. I know that there are quite a few engineers who would size the beams and goose neck for you for a couple hundred bucks. Drawings would be a couple hundred more. There are a lot of things to take into consideration when designing these things, and you want to make sure you are doing it safely.

Let me know if you need help locating someone, or want me to do it.

Fegenbush

/Currently my stamp is for Kentucky only, but that shouldn't matter for this job.

[MrBeast]

did some research, going with 12"x19 lb wide flange beams, 2x5" box tube for the edge of the deck, C4x5.4 channel for the cross members, setting them on 16" centers.

http://i40.photobucket.com/albums/e2...er/RENDER2.jpg

http://i40.photobucket.com/albums/e2...er/RENDER1.jpg

[ed mac]

you can buy trailer plans from northern tools
there good plans and DOT ap.

[SundownIII]

Yeah ed,

And I think Northern also offers a DVD on Welding 101.

You ever check it out?

Just thought it "really strange" that you would be the one to chime in on "trailer design".

[Lanse]

Good lord Sundown, have you ever said a positive thing to anyone on here? Seriously man, why do you insist on criticizing these folks at every chance that you get?

[CEP]

Mr Beast, all you need to do when building trailers, is take a protractor, tape measure, pad, and pencil to a couple trailer sales lots. Measure, and write down the dimensions of all the trailers that are in the category of what you want to build.
Sometimes the salesmen don't like this, go ahead ask me how I know.

[Rick V]

Ed Mac spotted something good. Here's the closet plan Northern Tool has to what you want to build - a mite shorter than your 36 footer. It's for a trailer of dimensions 32 x 8ft. 6in.
http://www.northerntool.com/shop/too...8241_200308241
I like what one review said, "I used these plans to build a 32 ft. hydralic drop tail trailer. My trailer differs from this one , but I used the plans for the construction details in the gooseneck, axels, and main frame." Seems a good investment for $40.

A bit of surfing on the Internet did not quickly turn up much more but maybe a more determined search could reveal something - certainly worth a try.
I kept running across comments on making sure you had local state DOT approval before you built your trailer - else you might not be able to run it on the road.

[CEP]

I have seen those drawings from Northern Tool, they sure make it easy, any 3rd grader could build a trailer with their drawings.

[SundownIII]

Lance,

Just so "I stay with tradition", you've sure got a lot of mouth for a young punk who can't make it more than one day on a job.

Maybe ed hack should buy one of those sets of plans from Northern and learn to weld. Then, maybe the gates wouldn't fall off his trailers.

Maybe after you've graduated (or at least spent a little time there) from the school of hard knocks, you'll have a little better understanding of why guys like Fat Bastard, me, and several other guys get a little fed up with the crap we see posted on the boards.

I'm beginning to think that maybe you just don't have thick enough skin to be hanging out on a welding forum. Maybe you should be looking for a job with the Democratic Party.

Really got little use for whiners. Signed on at 11 years old as a "carpenter's helper". Learned real quick what a shovel was for (digging ditches/cleaning up trash). Then I learned how to hang fiberglas insulation overhead in a crawlspace in the middle of the summer in 95 deg weather. You know what, I did anything/everything that was asked of me. By the time I was 13, I really was working as a carpenter's helper. By the time I was 15, I was running my own crew.

I'm 63 years old now, and I sure as HE11 don't need any advice from a "wet behind the ears, smart mouth punk" about how to be "politically correct".

[MrBeast]

I am not going to use the Northern Tool designs for one because those designs are not suited to my needs, for two, every tom dick and harry has built one, and they are hardly unique.

For me there is a challenge and a learning curve involved in this project, I do have the skill necessary to build it, and I am smart enough to figure out a design that will work, and I am well enough aware of my limitations that I will not be getting in over my head.

That being said, for me doing this project is as much about the experience and knowledge if not more so than the final outcome, although you can bet your bottom dollar what ever that final outcome is, it is going to be done right.

I really look at the northern tool designs as taking the easy way out.

[AMC724]

Have you ever seen the movie "Grumpy old men"?

Me either, just thought i would ask.


X2 on going to a retail lot with a tape measure, pencil and note pad
if for nothing else, to determine a main beam size

[MrBeast]

Originally Posted by AMC724

Have you ever seen the movie "Grumpy old men"?

Me either, just thought i would ask.


X2 on going to a retail lot with a tape measure, pencil and note pad
if for nothing else, to determine a main beam size

That is actually what I did, found a couple of manufacturers who listed the beam size, and it was the 12x19 W beam.

[Rick V]

Maybe I am missing something here... but can anyone just design and build their own trailer (yes, a 36 footer) and put it on the highway? Really?
I'd of expected there were are a pile of rules and approvals required - more than just on lights and brakes.

[MrBeast]

Originally Posted by Rick V

Maybe I am missing something here... but can anyone just design and build their own trailer (yes, a 36 footer) and put it on the highway? Really?
I'd of expected there were are a pile of rules and approvals required - more than just on lights and brakes.

Si Seinor. All it needs is a home built trailer inspection.

[Boostinjdm]

Originally Posted by MrBeast

Si Seinor. All it needs is a home built trailer inspection.

They don't even ask to see them around here if the empty weight is less than 2000 lbs. Interpreting the rules above that can be almost impossible in some cases. They don't want to see it till it's done either so I keep mine under the limit just to avoid some jackass telling me to move my light 2" forward or back after it's been hole sawed into the outer rail. I once even asked if an officer could stop by on the way through town and view the construction so I could get it right. Didn't happen...

There is a lot of absolute junk going down the roads, so I don't even know why I worry about it.

[MrBeast]

Originally Posted by Boostinjdm

They don't even ask to see them around here if the empty weight is less than 2000 lbs. Interpreting the rules above that can be almost impossible in some cases. They don't want to see it till it's done either so I keep mine under the limit just to avoid some jackass telling me to move my light 2" forward or back after it's been hole sawed into the outer rail. I once even asked if an officer could stop by on the way through town and view the construction so I could get it right. Didn't happen...

There is a lot of absolute junk going down the roads, so I don't even know why I worry about it.

There is a lot of junk, but here is how I look at it, as a fabricator, I am going to do the best job I know how, I am going to constantly look to improve, and I'm not going to worry about the standard because after all that is a minimum that I feel should be far exceeded.

As well I will not worry about what the other guy is doing, I will just do my best in the hope that it takes the business away from him and brings it to myself.

On the road there are no guarantee's, I have traveled over a million miles on America's highways, and the thing I have learned is that what is more important on the road is not being in a hurry, take your time, do your stuff right, don't get stressed and keep an eye out for the other idiots, and you will be alright.

[wnywelder]

[quoteMaybe I am missing something here... but can anyone just design and build their own trailer (yes, a 36 footer) and put it on the highway? Really?
I'd of expected there were are a pile of rules and approvals required - more than just on lights and brakes. ][/quote]

In New York at least, trailers over 2000 pounds have to be taken to a DOT inspection station before they can be titled and registerred. I would hope that they know what to look for to keep some of the dangerous stuff off the roads.

[wnywelder]

Double post.

[SundownIII]

MrBeast,

The problems with designing/building your own "one off" trailer are many.

Today's larger trailers (ie 36') are really "engineered" to give a design load capacity, while at the same time minimize weight and use the most economical materials available.

The "one off" builder simply does not have these tools at his disposal. As a result, the conscientious fabricator (which I think you are), will tend to "overbuild" his trailer. That results in a reduction of "load carrying capacity" while at the same time increasing costs.

I understand that this build also has a degree of "I can do it" involved, but realize that it's extremely difficult to compete with the "big guys" when it comes to design and buying power. For instance, you're buying a couple main beams. They're buying the stuff by the ton. Same thing applies to axles, brakes, etc., etc.

One option you may want to consider is finding a used trailer in good shape that "comes close" to what you really want. Buy it and modify it to meet your exact needs. Think you'll find that you're far ahead of the game both in capacity and costs.

[AMC724]

My momma always said "give credit where credit is due"


I would have to agree with sundowniii's suggestion about buying a used trialer.

[Donald Branscom]

Originally Posted by MrBeast

I am designing a goose neck trailer, it is going to have a 36 foot deck and an 8 foot neck.

I want to make the trailer durable, it will have a tandem dual setup, but at the same time I don't want to make it too heavy.

Does anyone know the formula for determining the strength of an I-beam?

Machinerys' Handbook has strength of beams from pin to pin when weighted in the center.etc.,but with a trailer, the WAY the weldment is constructed must be taken into account.

Probably the juncture or attachment point of the 8 foot beam to the trailer frame would be one of the main concerns. Why not use plans that can be bought, or are available from an approved source? Take the strain off of yourself.

HERE IS A SET of plans for $66.00 29ft. tandem 1500 lbs hitch weight.
http://www.glen-l.com/campers/queensbury.html

[MrBeast]

Originally Posted by Donald Branscom

Machinerys' Handbook has strength of beams from pin to pin when weighted in the center.etc.,but with a trailer, the WAY the weldment is constructed must be taken into account.

Probably the juncture or attachment point of the 8 foot beam to the trailer frame would be one of the main concerns. Why not use plans that can be bought, or are available from an approved source? Take the strain off of yourself.

HERE IS A SET of plans for $66.00 29ft. tandem 1500 lbs hitch weight.
http://www.glen-l.com/campers/queensbury.html

Are you serious? That is a camper.

[CEP]

Originally Posted by MrBeast

Does anyone know the formula for determining the strength of an I-beam?

Mr Beast these may help you, for this project or in the future.

[MrBeast]

Originally Posted by CEP

Mr Beast these may help you, for this project or in the future.

That is exactly what I was looking for! Thank you very much!