Tongue Bracing

[Bandit]

After the many discussions about the strength of the Tongue, I decided to strengthen my tongue with 1x1x1/4 angle iron.
I also welded my flooring tabs as suggested by Mike!
(I'll nip this in the Bud, the trailers upside down!)





Tab


She's making progress, I plan to extend the current trailer by 18" this weekend to make more room in the galley and have a full 80" for the mattress.

[mikeschn]

Very nice Jim,

Now when you build your subfloor, just make sure your subfloor covers the holes in the angles that you welded on to attach the floor with...

Mike...

[PaulC]

Jim, the expert welders around here may wish to comment on this but I thought that a tack weld every 6" would give much better strength to what you have done. I have been taught that big gaps between welds negates any torsional strength benefits when bracing.
Cheers
Paul

[angib]

Bandit,

I've run the numbers on your tongue strengthening (hey, it's oddball - I actually hand cranked it!) so we can all see what you've got.

Square tube 2" x 2" x 11g (0.120"): section modulus 0.511 in3

Square tube plus angle 1" x 1" x 1/4": section modulus 0.676 in3

So that's a 36% increase in strength, which makes your new tongue exactly as strong as a 2" x 2" x 3/16" square tube.

As the point of this is to make the tongue stronger in bending, your welds look just fine to me.

Andrew

[asianflava]

Is this more or less effective as a tension strap welded to the bottom of the tongue?

[WarPony]

Bandit, I like the angle iron bracing underneath the tongue. The silver paint is pretty nice, too.

PaulC, how does his welding of the brace compromise the strength?

[D. Tillery]

Andrew, I have a question. Are your figures for angle placed in that manner, without one side of 1"x1/4" placed hardway?

By putting that weld on the bottom of the tubing at the same area you welded to the sides, you have weakened three sides of the tubing at the same place. That's pretty nitpicky though. You should be OK.

If it does fail, you are probably still looking at a snap/break, as opposed to a sag with a tension strap, like Asianflava is talking about.

You are still in overkill mode though, which is a good thing.

[Bandit]

I really like the paint and its texture. We import a product line from Holland that uses a Hammerite paint. This is a Rust-Oleum product that is called Hammered. I can be applied right over rust. My steel is all new, so that is not an issue, but it is a very strong and durable finish.

The angle iron was just some added security. There are numerous gussets and braces throughout the tongue that I am pretty sure will insure the integrity of the tongue.

I do like hearing all the comments. They have all been positive and if the worst I hear is "it can't hurt", then I'm happy!

[Steve_Cox]

I liked the gussets and that hammered finish paint is pretty cool too! Sure is nice to have these great guys here to help sort things out, on the trailer/sailor forum all they do is obsess about tongue length and ball size...

[Bandit]

Speaking of Ball Size.
I use a 2" ball on all my other trailers, is a 1-7/8" sufficient for these trailers or does any recommend 2"?

[PaulC]

PaulC, how does his welding of the brace compromise the strength?

Warpony, When I had to rebuild the a-frame on my bobcat trailer I was told to brace it as shown and tack weld every 6" to minimise any sideways flexing of the brace. I'm not an expert in this department, I just do as I'm told Some of the time anyway
Cheers
Paul

[madjack]

Bandit, 1-7/8" is way fine...however, if all your other trailers are 2" you might wanna go thataway to avoid having to change out draw bars...that is what we did since we had several other trailers that all had 2" couplers on them
madjack

[Nitetimes]

PaulC, how does his welding of the brace compromise the strength?

Warpony, When I had to rebuild the a-frame on my bobcat trailer I was told to brace it as shown and tack weld every 6" to minimise any sideways flexing of the brace. Cheers
Paul

It's not so much compromising the strength of the brace but what you get when you use angle iron in that configuration is a piece of steel that can spread under stress between the welds. What could happen is that if the tubing starts to give way at a point between the welds all the angle will do is spread and flatten out thus giving none of the intended additional support. Paul is right, even 1" welds spaced about 6" and offset so the other side welds are between so you're welds from one side to the other are about 3" apart but not directly across from each other is about the best configuration. Hope this makes sense.
I won't say that what you have won't work just fine for your trailer, just that it wouldn't be my first choice. JMNSHO

[angib]

Andrew, I have a question. Are your figures for angle placed in that manner, without one side of 1"x1/4" placed hardway?

Yes, the numbers relate exactly to the section shown in Bandit's picture - that's why I had to hand-crank the answer, as I don't have a spreadsheet written to calculate properties of angles at 45 degrees from normal!

Is this more or less effective as a tension strap welded to the bottom of the tongue?

I'm not sure what 'tension strap' means here. If you mean a flat bar lying against the bottom of the square tube, then this 'added angle' will be much stronger.

If you mean the 'small truss' type of reinforcement (for example, as proposed by Guy) with a flat bar propped some way undeneath the square tube, then I would expect that to be a good bit stronger than this 'added angle' method. However this method does provide constant strength along the tongue - it is easy to design the 'small truss' reinforcement wrong so that it doesn't actually add much strength.

Andrew

[Kevin A]

[
I'm not sure what 'tension strap' means here. If you mean a flat bar lying against the bottom of the square tube, then this 'added angle' will be much stronger.

If you mean the 'small truss' type of reinforcement (for example, as proposed by Guy) with a flat bar propped some way undeneath the square tube, then I would expect that to be a good bit stronger than this 'added angle' method. However this method does provide constant strength along the tongue - it is easy to design the 'small truss' reinforcement wrong so that it doesn't actually add much strength.

Andrew

Andrew,
I believe this is the type of tension strap in question, The owner's name has been omitted to protect the innocent.