Tongue Extention

[mortsplace]

My tongue (on the trailer) is a little short and I need some help with extending it. What I have is a single tongue 2"x3" 11 Guage that extends 36" from the frame.

What I want to do is add 18" to the single tongue and also add 2'x2" 11 Guage A-Frame. This will give me a composite tongue that is 54" from the front of the trailer.

I looked at the section on calculating tongue strength but am a bit confused with figuring the composite tongue. Can anyone tell me if what I plan to do is going to be strong enough? I would (over)-estimate the trailer weight to be 1500 lbs fully loaded.

[Boodro]

Hi Mortsplace , what I see on your drawing is a weak point where you cut off the old coupler. With just a plate on the sides of the cut , the top & bottom of the cut would be a weak joint. What i would do is find a tube of steel that would just slide over the existing tongue & the new tongue & weld it in place . If you can't maybe a solid piece of stock that would slide inside the 2 tongues then weld plates on the sides & top of the cut???? Just a tought ,sicne you asked. good luck!

[doug hodder]

I've stretched a number of large truck frames and that's how we did it short of double framing it and that depends on what it was hauling. All your vertical strength will be gained on the sides of the tongue. Plating the top and bottom isn't really necessary. A fish plate on the outside of the tongue extension joint should take care of it. Of course you will want to weld the top and bottom joints in the tongue also. Another option...get some angle and box it kitty corner...I think with the A members also...it'll be bullet proof. Others may disagree...just my thoughts. Doug

[angib]

Ah, we've crossed over - I just replied to your post on the other thread!

Your plan looks good. Fishplating the sides of the centre tube can't do any harm, but I'm not convinced it's really necessary. You are now up against the problem with these three-part tongues - that the two side members will actually carry nearly all the load. The reason for this is that the middle member is much less stiff (because it's supported in the middle of those two springy cross-members) so it attracts less load.

I would add the fishplates as it gives you some assurance that even if the butt welds between the two tongue pieces aren't perfect, you won't get a crack develop. 1/4" fishplates are fine but you could use 1/8" as well - as the tongue is only 11ga (0.120"), there isn't a reason to make the fishplates any thicker than that.

Andrew

[Dale M.]

I pretty much agree with Doug and angib...

I believe you are on track with your plan...

Dale

[asianflava]

You could also make the cut a slash cut or 2 L-cuts so that you have a longer weld on the actual cut.

[mortsplace]

Thanks for all the responses. I had to revise the plan just a little . . again.

I had to move the A-Frame members in to make room for the stabilizers and also added some expanded steel to have a place to put a battery and folded up indoor/outdoor carpet. I will also have plenty of room to mount the front wheel jack on the side of the a-frame. In all I think it has worked out for the best. Now its time to get to welding and painting once again.

You are now up against the problem with these three-part tongues - that the two side members will actually carry nearly all the load. The reason for this is that the middle member is much less stiff (because it's supported in the middle of those two springy cross-members) so it attracts less load.

Andrew

I have already stiffend up the weak crossmember with 2x2 steel tube as shown below so that should help spread the weight better. Also had the tongue welded to the second crossmember. Had I left it alone I could very easily have replaced it by taking out only 2 bolts! Ohh well, live and learn.



and here is the revised plan.



Again, thanks for all the help.
LJ

[Alphacarina]

I'd say you're in very good shape - Added fishplates or not

If Andrew were to calculate (as close as possible) I'm sure he would tell you that your finished modified tongue is at least twice as strong as it was before you modified it

Don

[brian_bp]

Here's a thought: avoid any concerns with the splice in the central tube by not splicing it at all. Just remove that tube entirely and use the A-frame components as the tongue. If you want to mount the coupler on a straight tube, then use a straight stub at the end of the "A"... you could even just use the last bit of the existing tongue, with the coupler still on it.

If support for the mesh platform is a concern, two or three light cross-pieces might do a better job than the centre tongue tube.


Of course you would need to ensure that the A-frame components are appropriately sized to serve as the tongue by themselves... and this is only a suggestion for consideration, not a finished design.

[mortsplace]

Here's a thought: avoid any concerns with the splice in the central tube by not splicing it at all. Just remove that tube entirely and use the A-frame components as the tongue. If you want to mount the coupler on a straight tube, then use a straight stub at the end of the "A"... you could even just use the last bit of the existing tongue, with the coupler still on it.

If support for the mesh platform is a concern, two or three light cross-pieces might do a better job than the centre tongue tube.


Of course you would need to ensure that the A-frame components are appropriately sized to serve as the tongue by themselves... and this is only a suggestion for consideration, not a finished design.

That would be possible if I could easily remove the old center beam but since it is welded to the frame it is too much work.

Picked up my steel today ($33) and will be going to get it welded soon. I will also be adding another spring mount to move the axle about 6" forward to bring the hitch weight back down to account for the extra steel and battery at the front.

Thanks for everyones input.

[mortsplace]

Got the tongue extension completed.

[eamarquardt]

Hi,

The vertical strength does not come from the sides. It comes from the top and bottom surfaces being in tension and compression. That's why "I" beams have a top, bottom, and only one vertical element. What I have done in the past is to cut a square tube into quarters removing enough in the middle of each flat surface to fit inside the tube you are trying to splice. Then you weld the extension on using the 4 pieces as internal backing plates. Then you can grind off the excess weld and you have a nearly invisible splice (depending on how much effort you put into it). I sometimes drill 4 holes in the two pieces being spliced together and then plug weld the backing plates a ways away from the acutal splice point. Overkill I'm sure, but it doesn't cost any more or take much time.

I know this is a bit late, as it seems you've finished but maybe someone else can use this technique. Your finished product looks nice.

Cheers,

Gus