Double-checking composition of 5x10

[HKBB]

Have done a lot of looking around on this forum on information on chassis material, it's strengths, load capacity, tongue length, etc., and am finally ready to start welding - I think. This is the first time I've built a chassis for a trailer, and I'm a little nervous about it.

This is what I'm thinking of, but would really appreciate some knowledgeable confirmation that this is going to be a SAFE and sturdy frame. I know the 1/4" on the angle is a bit much, but it's what I have to work with. I've tried to get the drawing as close to scale as I can.



All comments appreciated. I really want to start welding next weekend!

[doug hodder]

You don't mention what you are using for an axle, but if it's a torsion, you can use it for one of the members and you could probably cut a member out of the front portion. I'd use 1/8" angle and cut the weight of those pieces in 1/2, but if you got a deal on 1/4 and that's what you have....it's WAY more than adequate. You could also save some weight with a .120 wall 2x3 on the tongue as well. I also think you'll find that you don't need the .125 plate for the tongue (as a base for a tongue box) or the gussets. Others opinions may vary and I'm not an engineer. Doug

[HKBB]

I'm using a 3500# standard spring axle from Southwest Wheel. ( http://www.trailerpart.com/35ktraileraxle.htm )

I put the gussets in the corners for stabilizers, and the plate up front is for a battery box/drawer - sort of. The front and sides of the box will extend upwards along the front, about 3/4 of the distance to the top of the trailer, and curve inward to merge with the roofline-radius. A little space at the head of the trailer for goodies.

[halfdome, Danny]

It appears as though you'll place your teardrop on top of the frame with the frame exposed.
If this is what you want then you can ignore the following.


If you were to reduce the width to accommodate the walls (overhang the chassis) plus 1/2" minimum space in between on each side you could make the rectangle portion that you call out as 10' just 8' long.
This would allow the torsion box of the teardrop to support the overhang at your tongue angles and reduce your steel use & chassis weight.
If you plan on leveling jacks in the rear corners then they would replace those flat steel corner blocks.
The rectangle area of my chassis is 57 1/2" x 96" for a 5' x 10' teardrop body with 3/4" walls overhanging the chassis. My tongue area with angle sides totals 54 1/2" plus the coupler ( 96" + 54 1/2" = 150 1/2" + coupler + 6" rear body overhang totals 13.5' overall), just to give you an idea of what others do. Danny



This photo shows the body overhanging the tongue area.
With the 6" rear overhang the front only overhangs 18".
It does involve some creative construction in the front area.
Notice in the first photo how the bike rack receiver tube sticks out to clear the 6" body overhang in the rear.

[angib]

Running that tongue arrangement through the Australian trailer rules gives a maximum trailer weight of 2400lb. I think that figure can be approximately doubled for teardrops (as it was written for utility trailers that get abused) so that puts the allowable weight up to 4800lb. Probably enough....

The one place that concerns me, if this trailer was going to be allowed to become really heavy, would be the front cross-member - angle isn't a very strong shape and even 2x2x1/4 isn't that strong. So if you wanted to double up the angle in that one place, I think it would more nearly match the huge strength everywhere else.

Just the angle, tube and plate in the frame weigh 285lb, so this won't be a light trailer!

Andrew

[HKBB]

Angib:

If I doubled that first crossmember, do you think it would be okay to eliminate the second one (the one shown at 24"), and move the third, centering it between the front of the trailer and the crossmember closest to the axle?
I am a little concerned about the weight. The materials I have to work with are pretty heavy, so the less weight in the trailer chassis, the better, as long as I don't wind up with that scary EVENT - tongue collapse.


Danny:

I started thinking about what you said, and realized that I hadn't allowed quite enough width - I'll actually need the chassis to be 62" wide. 60" for a queen-sized mattress + 1/2" on each side for 'wiggle' room, then an additional 1/2" on each side for the sidewalls (mounted on the floor with a rabbet).

I do plan on the sides to overhang the chassis. I'm planning on using 3/4" ply, using the cutout-framing/insulation method, with 1/8" interior and 1/4" exterior skin veneered. I figure the 3/4" won't be too awfully bad with the cutout-framing taking a lot of the weight out.

Also, after thinking about it, I could probably just weld a couple of 1"wide strips of the flat from the front crossmember to the angles as they come out toward the tongue, instead of having that (d**n) heavy plate at the front for the battery box.

And if I can find levelers that can attach to the chassis frame, I'll definitely get rid of the plate at the corners! I need to actually go look at some and see how they're attached. I've never seen any close-up - I'd just seen that most people that have them mounted them to corner plates.

All thoughts and comments are very much appreciated. I've only got one shot at this (It's taken me a year to save my pennies for this build), so I need to get the basic framework right before I start!

[eamarquardt]

I recently priced the materials for a 5X8 with a "A" tongue all out of 2X2X1/8 wall tubing. The tubing was $130 (including 10% sales tax) and the coupler was $30 bucks. It had five 5 foot cross members, two eight foot side rails, and the two pieces 6 feet long for the tongue. Plenty strong, IMHO, and tubing would weigh the same as your 1/4 angle but be much stronger. I realize a "good engineer" uses the materials that are available but I think for just $200 bucks (a fraction of the cost of the build) you could get a much stronger and easier to fabricate frame.

If you send me a PM I with your email I'll send you a sketch of the layout and how I figured the matierial. I need to print the diagram to scan it into a jpeg format to post it on the forum and my printer is down right now.

the si