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V10man
09-22-2009, 04:32 PM
I'm planing on making a tandem axle trailer. I have a question concerning frame material. The ones sold around here are made from angle usually 2x3x3/16" some use 1/4" and I've seen some using 3x4x1/4". With the side rails I'm sure it acts like a truss making the frame stronger.(see pic) My trailer plan is 5' wide by 16' -18' long(not sure yet) It will have 2 3500# axles for a 7000# GVWR. I don't plan on hauling anything more than 2 atvs and a Rhino, approx 2500 pounds. I think at 16' length the 2x3 3/16 would probably work. At 18' length I would feel more comfortable with the 3x4 1/4". When I went to price out the steel, the 3x4 was $5 a foot. I was thinking of using 2x4x 1/8 tube for the tongue. It is $3 a foot. This got me thinking. Couldn't I use the 2x4 tube for the frame too? Which would be stronger? Both would have the side rails. I think the angle would be easier to work with. Is it not even worth considering just to save $72?

Tom37
09-22-2009, 10:32 PM
From my armature/hobbyist point of view, I think I would use the angle.

1. The tubing has twice the area to harbor rust. (inside the tube)

2. The 180 that I have sitting on the shelf now, runs a very harsh hard to control arc on the high setting. I never used mine on anything critical. Someone else will have to chime in on if your machine will be acceptable. Maybe with proper bevel/prep and the ability to weld both sides of the angle.

I am not saying you should or shouldn't, but rather the way I may attack the project.

Good Luck, and please post pics along the way.

Tom

whateg0
09-22-2009, 10:48 PM
Here are some pros and cons of each...

Tubing does have to be sealed up or left relatively open to allow it to either keep moisture out, or to let the moisture escape. Angle does not have the interior to worry about.

Tubing is torsionally stiffer, so the trailer will tend to twist less than a trailer made of angle. A good compromise, and not much more costly than angle (by weight), if at all, is to use structural channel. Have a look at some of the other commercially made equipment trailers and car haulers. Many are made using channel.

For the same section height, vertical deflection will depend on the lateral thickness of the material used. In other words, if you use 3x4x1/4 angle, with the 4" leg up, it will resist sagging about the same as a 2x4x1/8 tube stood up will, provided you can keep it from twisting.

For a long light trailer, thinner taller material can be used to keep it light, but it will be more susceptible to damage.

If you are only going to be using it for the quads and the Rhino, you could also use lighter angle and build it like most utility trailers are built. This gives you a tall side, with plenty of places to tie down to. And it keeps things from sliding off the side.

Be sure to take into consideration how the weight will be distributed when loaded. If you plan, for example to load the Rhino at the back, you will want the axles centered farther back than if you put it in the middle or at the front. Just remember that you want approximately 10% of the trailer's weight on the tongue.

If you visit Big Tex's website, you can download datasheets for their trailers. You can see what materials they use and where the axles are located.

You didn't mention what material you are going to use for the deck. If you want light weight, expanded metal is the way to go. It's also nice for quads if you plan on getting muddy, as the mud can fall through instead of accumulating and getting slick on top of wood or diamond plate. However, it adds almost nothing to the structural strength of the trailer, requiring the frame to be able to support itself safely on its own. If you use wood or solid metal for the deck, you can plan for it to provide some strength to the trailer.

Just my 2.1.

Dave

vicegrip
09-23-2009, 03:03 AM
Angle stock, is not intended for serious cross-loading.
It is to be used for ties, where it caries tensil loads only!
It provides two faces for bolting to other members that
are 90 degrees to each other.

Use box tube !!

Vg

V10man
09-24-2009, 04:53 PM
Thanks for the advise. I havn't figured out the floor yet either. Expanded metal would be Ok but I'd have to add more support to stop it from bending. Wood and expanded metal are about the same cost(slightly more for the metal) when you figure in hardware. A 4x8 sheet of 3/4 #9 is $45. I can find 5x10 but I dunno about the cost. Here are pics of the first trailer I made. Here I used 2x3 tube for the frame because the sides are removable. The floor joists are on 12" centers. So far the expanded metal floor has not bent. http://home-and-garden.webshots.com/album/555492796zLnBId

The Clarke 180 works pretty well. Of course I have not used any other machines so I can't compare. I have practiced on some 3/16 and 1/4 stock and it seems to do well there too. I do feel however a biger machine would be better for this large of a project. Kinda like building an ark with a hand saw.

calweld
09-24-2009, 05:17 PM
Don't think of expanded metal, think of catwalk grating. 3 or 4 pounds per square foot, it's structural. Probably still less weight than wood.

Angle iron vs. tube. Tubular structure, in itself, allows for far more flex, and possible cracks. Run a crossmember to one side, then one starting on the other side of the tube, two inches between them.

Always a well-distributed load???? should be fine.

Myself, I've always preferred real structural shapes; angles, channels, I-beams. Weld one side, weld directly on the other side, same location. You create continuity between the various structural members, rather than "spaces". Not gonna have a box tube, distorting, because of some concentrated load or the other.

vicegrip
09-27-2009, 09:56 AM
Angle iron vs. tube. Tubular structure, in itself, allows for far more flex, and possible cracks. Run a crossmember to one side, then one starting on the other side of the tube, two inches between them.

Always a well-distributed load???? should be fine.

Myself, I've always preferred real structural shapes; angles, channels, I-beams. .

Wrong.........
choises from best to worst are;
Box-tube rectangular ........wider section paralell to cross-load
I-beam
Box-tube square
Channels......prone to twisting
Angles......no good cross-load srenght at all.

Zrexxer
09-27-2009, 10:08 AM
Angle stock, is not intended for serious cross-loading.
It is to be used for ties, where it caries tensil loads only!
It provides two faces for bolting to other members that
are 90 degrees to each other.Use box tube !!VgAnother case of trying to apply engineering theory to a single component with no consideration of overall deign or real-world application. Look around you, there are hundreds of thousands, if not millions, of safe, sturdy, well designed trailers on the road ever day, from 4 feet to 20 feet or more, all constructed of angle and certainly carrying heavier loads than a couple of ATVs.

vicegrip
09-27-2009, 11:59 AM
Another case of trying to apply engineering theory to a single component with no consideration of overall deign or real-world application. Look around you, there are hundreds of thousands, if not millions, of safe, sturdy, well designed trailers on the road ever day, from 4 feet to 20 feet or more, all constructed of angle and certainly carrying heavier loads than a couple of ATVs.

Your grammer, spelling, and sentence structure, are sure a lott better
than mine! I'm so happy I've been able to inspire such a good essay.

I am now so convinced you are correct, I'm going to look at semi-trailers
and in my niehbor's basements, to see all the wonderfull places
that angle should be used to make this a better / safer world.

Cheers
VG

vicegrip
09-27-2009, 12:05 PM
I'm on a roll now !!!!!

I'm flipping nervously (all be it) excitedly thru the yellow pages;
so I can find a lawyer to make me a legal draft, so I can send it
to the factories where the many machines I have designed and built
are buisy clicking and buzzing away, destined for certain failure;
because I used box-tubing for the main frames, instead of angles.:eek::eek:

I hope I get these off in time to avert dissaster.:rolleyes:

Pfweeeew!
vg

FWI
09-27-2009, 01:51 PM
Man just find a trailer you like and take a few dimensions. Then the engineering part of materials has been established. Which means your welding ability and welding schedules are the only question. It sounds like you are working that out currently. In KY in order to get plates for a home made trailer you have to have in inspected.

aametalmaster
09-29-2009, 12:35 PM
I have been building trailers for over 30 years with the same 3x5 angle design on some models. Now the newer angle trailers are pretty light duty thats why they add the top rail to keep them from bending. The only one of mine i know of that bent was a guy ran a little dozer up on his borrowed car trailer and made a nice arch in it. Had he blocked the back while loading it prob would have been fine...Bob
http://s110.photobucket.com/albums/n86/aametalmaster/Trailers%20i%20have%20built/

Mr Meck
10-04-2009, 12:32 PM
I would nix the 1/8 square tube for the tongue and use 2x4 x1/4 tube for the frame including the tongue for the following reasons. I weld at a dirt moving company. We made an 8 x 20 trailer with no sides for hauling various stuff. Everyone said it was good for 20 ton. I begged to differ and stated the trailer was only good for the least rated item. Like the two 6k axles made it a 12k trailer or 10k at best. The 4 tires rated at 2500lbs each made it an 8k trailer, the 10k 1k hitch was more than the tires so the tires set the weight load limit.
Same trailer was loaded with from back to front with 2 scraper tires and a 3406 motor. Driven down a rough road the tongue folded at the trailer front do to the bounching effect. So much for proper loading.
Replaced the tongue with 2x4x1/4 and asked if ya knew the trailer was bounching why didn't ya slow down? I was only going 55. I continually see dual axle trailers loaded with considerable excess tongue weight so much so the tow vehicle is shooting for the moon and hardly steerable and the rear trailer axle hardly carrying any weight.
In this respect consider what ya want to haul. 2 ATVs and a Rhino. One aft of axles , one over axles and one forward of the axles. Now through in 65mph and rough roads. Will your design handle the flex effect of 2k aft, 2k centered, and 2k forward of the axles with angle iron or 1/8 tube for its life time or will I see your trailer folded on the side of the highway?
Some nice trailers there AA.
Don't forget to plan the trailer weight into the GVWR.

Rancher Bill
10-04-2009, 02:18 PM
Mr Meck has it right.

It seems you are building a 7,000 trailer in some areas and a 3,500# trailer in other areas.

Why don't you make it a single axle 3500# trailer. You only want to carry 2500#.

When this gets sold at your estate sale many decades from now, somebody will go "look Double Axles, it's a 7K trailer, I'll just cheat once and put 9K on it. What's it gonna hurt" They will be surprised at the outcome.

A quick way to check yourself is to get you steel weight calculator out and add up the weight of your trailer. Your weight should be pretty close to professional trailers that you can find all over the internet. If you are not, you should be asking why. You are either overbuilding or underbuilding.

calweld
10-04-2009, 03:41 PM
Wrong.........
choises from best to worst are;
Box-tube rectangular ........wider section paralell to cross-load
I-beam
Box-tube square
Channels......prone to twisting
Angles......no good cross-load srenght at all.

On a trailer, I disagree. Tubing, by itself, yes, is stiffer. The problem is, most people, when engineering with it, cut sizes and wall thicknesses down, to get the same stiffness, with less weight. And also, say you are welding structural members, on either side of another frame member. Do you not have a hollow space between them, if you are using tube? Also, it is far easier, to rip a member out, spring hanger out, weld, wall in the tubing and all, than it is, to do the same, with any structural shape, whatever the thickness, noting there's usually another piece stiffening it welded directly on the other side of the wall or flange.

Crawl around under any 28' flat, 48' or 53' flat, any lowboy, any tongue-pull or gooseneck equipment or backhoe trailer, you will rarely see any tube in the frame.

One thing you will also notice, crossmembers. Very important, the strongest trailers, that can take the most concentrated load, have the more closely-spaced crossmembers. This is what keeps angles, I's, and channels from bending and twisting under a load. They don't have to be heavy, they just have to be there, and the proper size and design to be stiff enough to do the job.

Even when I stretch truck frames, locating, placing, and properly installing crossmembers is almost as important, as how the splice is done.

Ferntj
10-06-2009, 10:15 AM
Angle and box tube have equal stiffness when they are sized equally. By that I mean that 1/8 wall 2x2 square tube has the same moment of inertia as 1/4 thick 2x2 angle. They will have the same deflection when loaded. But the angle will fail before the tube when the load increases because the angle has a larger distance from the neutral axis to the extreme fiber and so has higher bending stress.

It is possible to design a safe structure from either material.

old blue
10-06-2009, 11:57 AM
Now that all the experts have come to no agreement whatsoever, leaving you totally confused go HERE
(http://www.trailerplans.com/)
and get busy on your project.

V10man
08-17-2010, 10:00 PM
Well alrighty then. My plans have changed somewhat. Was going to build a single axle 5x10 trailer just to haul my Rhino. During my parts search, I found a travel trailer frame on Craigslist. It's 13'x5'2" wide. 3" channel with what looks like 1 1/2"x2"x1/4 crossmembers. The tongue is 4" channel. I paid $225. It has brakes. Oddly, one spring pack has 8 leafs and the other only 5. Maybe all the heavy stuff in the RV was on that side??

whateg0
08-17-2010, 11:35 PM
I suppose that the trailer weight could've been heavily biased to one side, but I doubt it. I would suspect that somebody has broken one spring pack and replaced it with a different one. It could even have the same rating, but I think it would be near impossible to know for sure. For example, I've seen 1750# spring packs with 3 leaves and others with 5. Are they roughly the same overall thickness?

It is hard to tell from the pics you attached (they are kinda small), but it almost looks like the frame is made of tube instead of channel. Maybe there is a plate welded to the tail end of the rails that causes the black rectangles in the last pic. Looks like a good start to a trailer, though. I do kinda wonder if the 3" channel is heavy enough to resist bowing, but the wheelbase on the Rhino is probably short enough to keep the weight over the axle ok.

Dave

BC Iron works
08-26-2010, 02:18 PM
i would spend $40.00 and buy northern tools
blueprints for trailers there dot approved and
have a materials list. i have 3 sets and there well done

mustang0
09-01-2010, 11:52 AM
Do you have an aproximate cost for just the metal for that car trailer and did you build that one?

urch55
09-01-2010, 04:55 PM
Design flaw???
Factory built 7x14 dump trailer, 60" sides. 14,000 gvw.
Main frame 2x6x3/16" rec.tubing maybe 1/4" the ends were capped. Sub frame 2x3x1/8" Rec. tubing. Tongue 8" 13.75 lb channel.
http://www.hobartwelders.com/weldtalk/attachment.php?attachmentid=31699&d=1283377439

SidecarFlip
09-01-2010, 10:33 PM
Might be the salt air and constant overloading......:D

whateg0
09-01-2010, 11:25 PM
I guess it depends on how you define "design flaw". To me a design flaw is something obviously wrong, like putting an engine mount through the middle of the serpentine belt. This looks like it is a weak design, but it has worked for awhile. It would definitely benefit from a gusset, though.

Dave

Blazey10
09-02-2010, 09:20 AM
I would install a two jacks on that dump trailer at the bottom of the cylinder.

urch55
09-02-2010, 02:14 PM
I would install a two jacks on that dump trailer at the bottom of the cylinder.

Blaze,
How would that help? Before you answer think about how a dump works, do you or do you not drive out when the bed is dumped to empty the contents of the bed. So if you had jacks or some kind of stands under it that would be defeating the purpose.

Dave,
A weak design that has a high potential to fail, higher than most why would you not call it a design flaw. That "weak design" would work on a much smaller trailer.
Using that design there would be two ways one of which using different materials it could have been fabricated and it would hold up fine.

Blazey10
09-02-2010, 02:33 PM
Put wheels on the jack. Just for temporary until it's fixed right.
Really doesn't mean I would do it. Just don't now how much work is needed as a whole for the trailer. Looks in pretty bad shape though.
Just throwing it out there. Looks as if it may have been overloaded.:p (really)