View Full Version : Trailer advice again

05-01-2008, 09:24 AM
I am still thinking of this trailer. It will probably be awhile before I ever attempt it. Had a couple of questions that are probably basic but wanted to ask a professional:

1. I got my 4 10 foot sections of 3x3x3/16 inch tubing and layed it out on the garage floor. They were old material stands at work. A couple did not seem exactly "flat". I mean that in the middle I could see light coming through if laying on the floor. I could also "rock" it with my hand on the floor. Now, it could be that my concrete floor is not perfectly level, I don’t know. It is not realy bad. Would this cause a problem? Maybe one side of the axle would be slightly higher than the other?

2. I layed the metal out in trailer fashion. The trailer would be about 10 feet six inches long. I was thinking of using a 6 foot axle. At six foot wide, it looked a bit odd, probably because it is only 10 feet long. Maybe there are not a lot of trailers out there this short that are 6 feet long? Is it still ok to make that wide? Would there be driveability problems,hard to keep on my side of the road, etc? I am thinking if I had a back gate it would really be a large back gate that wide!

3. I need to find some cross members. At work, for scrap price I can get some c type channel that was used on a conveyor. It is very strong they told me. I think it is three inches. If the frame is 3 inch square tubing, I am assuming this 3 inch channel will have to be welded in 2 inches down on that tubing so 2x wood material can be used for the bed. That would leave one inch of cross member to be welded onto the tube. Is that acceptable?

4. There are still some old material stands at work I noticed. These are however 5x3 inch rectangular tubing. It is 3/16 or maybe 1/4, not sure. I can get cheap. The thought crossed me, I could use these on both ends, extending the length of the trailer to 10 feet 10 inches. That would leave me some of my 3x3x3/16 tube left to work for a tongue.

I have located a business that sells new axles. They have a 3500 lb axle with springs and bubs for 100 bucks. Was thinking of using that and maybe some time later having the opportunity to add another axle.

Anyway, before building I ma going to practice welding and taking a jack and trying to break apart. Also, I have a weld shop that when I build it will look it over and add welds where maybe mine are in question. It wont cost me anything as he is a friend of my dads. I think I can get it sandblasted there too for nothing. I just need to grab this material at work if it is good for this project before someone gets it.

05-01-2008, 10:14 AM
If I had a choice i woud try and use the 5x3 tube for the frame as opposed to the ends. You will get more strength. The 3" channel may be stronger than the 3x3 tube also. I would need the exact sizes to know for sure.

I would not set the chanel down but weld it flush with the top of the 3x3. You can deck over everything. If you don't want to see the edges of the wood you can add a piece of angle to the sides to hide the 2x's. If you can make the 5x3 chanel work then I would set the cross members down by the thichness of the floor. Don't forget if its just a small trailer plywood may be a better lighter choice for your deck.

6'x10' is sort of odd looking but if you look at dump trailers they are frequently 6x10 or 6x12. The idea being they have less weight leveraged at the front to lift.

Keep this in mind your trailer will get heavy fast. Standard 3" channel weighs 4#/ft. 3"x3" 3/16"= 6.9#/ft, 3"x3" 1/4"= 8.8#/ft, 3"x5" 3/16"= 9.4#/ft, 3"x5" 1/4"= 12.21#/ft, 2x decking will also add weight. I don't have a ready weight / ft but you can just lay a piece on a scale to figure it out. Add axel and tires, jack, sides and gate, 3500 lbs can go real fast. Also check with your local DOT at 3500lb you may have to have brakes.

If you want to tell if the steel is bent set it on several 2x4's off the floor. Then pull a string line tight down the length and stick 2 equal sided blocks between the line and the steel, say a piece or 3/4" pine, one at each end. You can then measure from the line to the steel and see if it has any changes in measurements. The line must be tight, as tight as you can make it. This will prevent the line from sagging and give you a dead straight reference.

05-01-2008, 11:11 AM

If I put the decking on top,wouldnt that make the trailer too tall? WOuld it cause problems if I added a fold down gate?

Think I should make it narrower?

05-01-2008, 12:50 PM
Addressing the straightness issue: Very few concrete floors are perfectly flat, there are always little dips in them. To determine if it is straight sight down it from end to end. If it is bowed you can heat spots red on the high side and and shrink it back straight.

05-01-2008, 01:10 PM
As far as being to tall, 1 1/2' will not make a difference. As far as the ramp, depends on what you plan on loading. I can run my mower over just a plain 2x10 to get it into my truck to take it to get it serviced no problem. You could put a cross member near the rear frame to take the load and bevel the back ends of the 2x's it you wanted to. You could also just set the pivot pins up higher so the ramp is even with the floor when lowered, which is what I would do.

You can also make a set of ramps that store under the trailer that you just pull out and set up. Generally this is what I would prefer as it lets me have things loaded with a lift from the rear.

I prefer the trailer to be as wide as possible so I can use it in as many different ways as possible. A lot of times I use a trailer because I can't get something to fit in the back of the truck. Truck is 60" wide at the top of the bed and about 50" between the wheel wells. A 6' wide trailer will take a section of stockade fence if you load it just right, a bit wider would be better. All depends on how you plan on using the trailer.

It's a toss up for me if I would want a trailer with sides or not. A great many times it would be nice to have a flat deck trailer to load larger items with a forklift, say drywall or a pallet. Sides are nice for bulk items like construction debris or mulch. I have a set of removeable plywood and metal frame sides that we put on the trailer. Not super strong but it keeps loose stuff in the trailer.

05-01-2008, 01:31 PM
Addressing the straightness issue: Very few concrete floors are perfectly flat, there are always little dips in them. To determine if it is straight sight down it from end to end. If it is bowed you can heat spots red on the high side and and shrink it back straight.

If my floor is not perfectly flat, is it ok to build the frame and weld everythign up on it?

I really appreciate your help guys! I would liek to have a fold down gate too that would serve as a back gate and maybe some sides.

ALso, I am fighting with what kind of tongue to use, standard A frame or a straight tonge with sides that triangle out and attach to the trailer, if you know what I mean.

05-01-2008, 01:56 PM
Define "my floor is not perfectly flat". If it's only out by a little bit you should be OK. Some floors are relatively flat but slope in one direction for drainage. That should be Ok. If the floor has a compound curve or something goofy you might be better just setting up some saw horses and working off them. That way you can level everything up with shims or trimming the saw horse legs and not worry about it. Makes it easier to weld also.

I would set up two saw horses on each end and clamp the cross rails to them. Then lay the long rails on the cross rails at the very ends. Put a 4' level on the rails and shim the saw horses until all sides are level. This will give you a good idea how out your floor is. You can do the same thing with a water level or a good laser level also.

I personally would consider setting up a center pivot on both ends. You need to make the pivot taller than 1/2 the width of the frame so you can turn the frame to weld. Put a set of saw horses under the frame after you turn it or a set of jack stands. This will let you weld almost all your joints on the flat. You can also do this if you have the ability to lift and flip the whole frame, say with a forklift or an A frame hoist. The pivots are sort of like an engine stand. If you want I'll see if I can find you a pict and email it to you. Just PM me with your email address.

As far as the tongue, I would build an A. Run the A from the side frames up past the front rail to where the hitch will go, underneath the frame. This gives you 2 good points to weld each side. You can always weld a piece of tube on top of the A to bring it back up the 3" to match the height of the original deck if needed.

05-01-2008, 02:39 PM
stryped You have mail. Info e-mailed.

05-01-2008, 02:58 PM
Thanks. By the way, does anyone have any trailer plans? I would be interested to look.

05-01-2008, 03:01 PM
I should have mentioned it before. Northern tool has a bunch of different trailer plans you can buy. They run about $20-40 if I remember.


05-04-2008, 03:06 PM
Champion trailers has good information on their website. I assume since you have welding ability that you are fairly handy so plans should not be needed. Don't waste your money on them. You are making a trailer. Its much like making a simple deck on your house, just a rectangle with supports and wheels. Utilitytrailerkit.com has the best prices in the country on axle kits. I have purchased 5 at a time from these guys and the price and shipping get better the more you order. If you build 4 and sell them, you can build yours for free. If you build 5x10 you will get more from your material because it is usually sold in 20 ft lengths.
Have fun

05-04-2008, 09:33 PM
I've built a few trailers for myself over the years.
Everything from a yard trailer to a 20' gooseneck flat bed trailer and a 16' bumper pull stock trailer.

Like the previous poster stated, basically your building a deck.
Then adding a tongue to the front (make sure it's centered)
Then adding an axle. (make sure it's centered L&R and vertically with the hitch.)
To do this, use a string attached at the same spot on each side of the axle, mark the center of the rope and pull it up to your hitch to make a triangle. Once the center mark on the rope is under the hitch you know your centered. Double check L/R center under the deck, then just bolt it on.

The most critical part is where to put the axle.
Do not put it in the middle, 50/50 load, it will be squirelly at best at highway speeds, if it makes it that fast. Very dangerous!

You want 5%-10% of the load to be on the tongue. The further back you go the more tongue weight you add. Also the further back you go, the easier it is to back up.

That is by far the hardest part of building a trailer and is determining what you plan to haul most with it, or how you plan or can load it, etc.

05-07-2008, 01:48 AM
Before and after pic's of the frame from a 15' travel trailer I stripped down and built into a flat deck trailer.