Tandem Trailer

[JWBIRONWORKS]

I've been scrounging the material to build an 18 foot tandem axle trailer most of the year this year. Last spring I bought 6 mobile home axles complete with springs and 2 also had brakes for $50. I kept 0ne pair and sold the others.
I came acroos some 2"x2"x1/4" square tubing in August. there were 10 pieces 7'4" long and quite abit of short pieces 4' and less.
Two weeks ago I also got quite alot of 4"x4"x1/4" square tubing from a factory that was tearing out some old eqipment. Any gussets or crossmembers were bolted on. No welds to cut and clean up.
Just to throw this out there here is my plan. I am going to use the 4x4 for the frame and the 2x2 for crossmembers.I will be using treated 2x8's for the decking. The trailer will be 6'6" wide x 16' long with a 2' dovetail. I realize it will weigh more than an angle iron trailer but it will also be stronger. For the savings of the cost of buying a complete trailer the extra weight is acceptable. A rough calculation is about 1300 lbs once complete.
I am attaching a PDF of a cad drawing I have made of the trailer. I will be using the trailer mostly to haul metal and scrounged treasures, possibly a car or truck once in awhile. Does anyone see a problem with this design that I have missed. Or any suggestions toward the design of the trailer.
Any input would be appreciated.

JWB

[Ed Thomas]

JWB: I have a homemade double axle trailer (not made by me) which has house trailer axles. To get it safety inspected, I replaced the brakes. Finding them was harder than I expected. My impression is that it is no longer legal here in Virginia to make trailers from those axles, so before you get too far into it, check your statutes there in Indiana. Even if it were legal, I'd have reservations about using them. The brake linings are very thin. The owner of the camper trailer store where I finally found the linings told me that they are designed to move a house trailer ONCE. Then the brakes are supposed to be replaced. Naturally the hauling distance would vary, but the point is that there is barely enough pad to initially pass an inspection, not many subsequent ones.

Another no-no is that my wheels are those old funky bolt on wheels... not the lug nut type. These are apparently not legal on new construction.

I might have my facts all screwed up, but I just wanted to let you know it MIGHT be an issue.

[HWooldridge]

Like Ed said, I have been told on multiple occasions that bearings and brakes on mobile home axles are not built for more than one move. Everything is made on the cheap. Doesn't mean you can't upgrade but it probably should be done before too many miles. I have built several trailers and always buy my undercarriage new because I want all the moving parts to start out brand new.

Your ideas on box tubing and 2x's are quite sound. You can also buy trailer deck screws that help the wood installation. The screws are about 3" long, self-threading tip and have a torx drive, countersunk head. You drill an undersized pilot hole thru wood and steel, then run the screw in until flush.

Everyone does it differently but I put the front axle in the center of the box dimensions with the rear axle set so the tires will clear by 3-5 inches. Some of that spacing is determined by the fenders. The tongue material is then usually enough to give you 200-300 lbs on the hitch so it tracks well.

[Chris Pook]

the mobile home axles are illegal here in bc and in alot of staes in the us.

I built my own 18' trailer lats year and had a chance to get some of those axles very cheap...after researching them I went and ordered some proper axles.

most people go for a 60/40 split on the axle placement.

[king fish]

I have made 4 or 5 trailers with mobile home axles in the past . I've found the newer ones to be not worth the time to use. In the last 10 years they have been made very cheap.

[henerythe8th]

I took a quick glance at the .pdfs and the first thing that I noticed was that there were no "members" to mount the springs of the axles to.

My best advice would be to go to the local dealer and look their new trailers over real well. The people that mass produce those types of things have them pretty well figured out.

I'm not saying that you have to use the same size material, etc. I am just saying that they're pretty good at what they do and the methods to get from here to there...


Henry

[JWBIRONWORKS]

First off Thanks to everyone who has replied.
I am checking into the legality of the trailer axles. They have a tag on them that rates them at 6,000 lbs and seem to be heavy and well made. This is the fourth trailer I have made but the first tandem trailer. the others were motorcycle trailers. 2 were to carry 3 motorcycles at a time and one small one to pull behind my motorcycle for camping and such. I have used trailer axles on both the cycle carriers with no problem. But those I built in the early 90's so I will check to see if Indiana law has changed.
Henry the axles will mount directly under the 4x4 box beam frame rails using a 60/40 ratio. Sorry the pdfs aren't real clear and don't show any details.
Ed, I will definetly have to replace all the brake copmponents and at least repack all the bearings if not replace them. The axles sat in the pasture I bought them in long enough that the brakes are frozen to the hubs. I will give them a good going over and once I find out if they are legal for new construction I will decide what to do.
I plan on starting on the frame Thursday. I have been looking at dovetails and ramps on other trailers and think I have a basic plan on those. I also intend to make my own fenders too. I priced treated 2x8's tonight Ouch once again thanks for all the input. It makes a person consider things they might otherwise have overlooked.

JWB

[irnsrgn]

the rule of thumb is for every inch the axles are moved from center, the load moves 2 inches. If you have ever pulled a trailer that was loaded too heavy behind the axles, a dip or such will actually pick the rear wheels of the pulling unit up off the road and it may set it down quite a ways to either side of where it picked it up and it sure makes for an exciting moment if you live thru it.

Tortion bar axles fasten right to the frame and the springs are inside the axle, which makes for a lot lower trailer height. Most new Cargo Trailers have torsion bar axles under them now for that reason.

Note - in some out of the way place not easy to find put some means of identification on it, people just love to steal those trailers.

Gooseneck hitches in pickups are generally installed 6 to 10 inches infront of the rear axle to keep the vehicle front axle from coming off the ground in a hard pull and also to put some of the trailer tongue weight on the front axle.

[aametalmaster]

You have some good ideas so far and here is another. I built trailers 500 in all to sell. I never put used axles on them always buying or building new ones. There is alot of difference in trailer axles and mobile home axles, being the axle tube thickness, magnets, shoes, and backing plates for the drums everything else is about the same. Anyway when you make up the axle assembely weld the hangers to some 1/2"x3" flatbar the length of both axle sets plus a few inches on either end. That way you can bolt the sub assembely to the springs, put on the tires and roll the whole works under the frame. Then you can move the frame around to get a feel for tongue weight and such, then just stich the 1/2"x3 to your tube frame, it will also make your frame stronger where the hanger would have welded on to the tube. We put our tandems 1' back from center, so the center of the rocker bolt would be 1' back from the trailer center. Just my .02....Bob Metal Master Fab
Yahoo! Photos - Trailers i have built

[JWBIRONWORKS]

aametalmaster,
Thanks for sharing the pics and thanks for the idea on the axles. Those are some fine looking trailers. I like the tilt trailer best.
Just thought I'd put up some pictures of what I have so far with 3 1/2 days of work. I am going to go ahead and use the trailer axles since I already have them. Will have to pull the hubs and check everything before I get to far along.
The frame is sitting upside down on the leveling stands. The dovetail is attached and the axles are shortened but not wrapped yet. The tongue is welded in place also. Lots to think about before next Saturday.

JWB