Am I on the right track?

[Woodbutcher]

Well, the steel for my trailer is in and we will soon start cutting the parts.
The overall size will be 56" wide (with a Flexride Torsion Axle) by 108" long. The main platform is 2x2 x.125 tube steel with mitered corners. There will be 3 cross braces. I will weld 2x2 angle clips to bolt the floor down.
Now my biggest question is, I want to use a tongue box. My Jeep tailgate has about 30" of swing. I was wanting to use a 48" tongue giving me about a 16" deep box. I have ordered 2x2x.250 tube for the tongue and the A arm tongue braces for strenght.
Will any of what I have planned cause me any problem?

[madjack]

...nope, sounds plenty strong enough to me...................................................

[angib]

Another good worked example for the Aussie tongue strength rule. I think you're describing the composite tongue in this diagram:



Let's assume your angled braces extend out 24" from the frame, so L1 is 24" and L2 is 48". 2"x2"x0.25" tube has a horizontal and vertical strength of 25,300lb-in.

So the strength checks are:
Vertical at L1: max weight = 25,300 / 24 / 0.5 = 2,025lb
Horizontal at L1: max weight = 25,300 / 24 / 0.5 = 2,025lb
Vertical at L2: max weight = 3 x 25,300 / 48 / 0.5 = 3,163lb

So you're good to go to a trailer weight of 2,025lb according to the (strict) Aussie rules.

Using 2"x2"x0.25" tube for the angled braces is rather overkill - you could use the lighter tube and still be as strong.

Reducing how far out the angled braces go will affect the strength of your tongue, as it is already limited by the strength of the single tongue section. So if the angled braces only went out 20", the max weight would drop from 2,025lb to 1,807lb. Still plenty!

Andrew

[Woodbutcher]

Thanks for the replys. You are right I am using the composite tongue design. I appreciate the calculations. I was going to use the .250 for the angle braces because I had to get a 24' piece because it worked out cheaper then getting cut to size tube.