Weld a new tongue - strength?

T_C

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On my last trip I may have been a little forgetful. The leg on my tongue was left down while towing out after the first night of camping, never scraped... until I hit the speed bump leaving the state park. Doh!! Didn;t just scrape, bent it back pretty good.

Making lemons out of the situations... I was talking last year of making a new tongue anyway, use aluminum instead of steel, maybe a little longer. It's not a difficult piece, just 2" box steel, one offset. Coupler on one end and a ?" cross bolt hole on the other end at the axle. A pair of plates are welded on the sides at the offset to reinforce it.

My question is on the cutting and the re-welding. What is best way to cut for the welding? Does it really matter as the side plates are really what take the load of the tongue trying to be pulled apart? Simpliest for me is to make a pair of parallel angle cuts, then reverse the middle part and have them weld the butt end and the weld on the side plates.

Is there a better way to cut? Straights and angles? Beveled?
tongue.gif
 
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T_C,

How quick do you want the transition? And how much lift?

Option 1: cut the pieces an the same angle, 22.5 degrees will form a 45 and 45 will form a 90. The smaller the angle, the slower the transition. Simply trigonometry, but I could help you with the lengths and angles with the above questions answered.

Option 2: Buy an extra 6" to 9" of square tube and stack them with an overlap. This would give a 2" offset.

Neal
 

STinner

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Take a 1/4 grinding wheel on a 4 1/2 grinder and grind a groove the width of the grinding wheel half the thickness of the base metal-weld this groove full and a little on top. Flip the piece over grind out another groove down to the weld and fill this one with weld. Now you have close to a 100% weld. Grind smooth on both sides and finish however.
 

TOS

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I like the 22.5 degree cut plan.
Not sure how much you intend to tow or the strength of the 2" Sq. Aluminum. If you weld bolsters or gussets on/in the angles, it should be as strong as the straight and work ok.
 
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T_C

T_C

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Sorry, guess I should have explained it better.

I'm looking to re-produce what I have now in steel, but use aluminum. The current tongue is 2" box, 16 gauge (.07 or less from what I can measure at the moment) steel. So is 1/8" aluminum 2" box a fair equivalent"

Overall length is 74", offset is 4⅛". That makes it about a 31? angle between the pieces. Lower piece under the trailer is 31" from axle to transition.
20160906_194402.jpg
I know 1/8" aluminum is not exactly standard trailer material, but this is a motorcycle camping trailer. The AlKo axle under it is rated at 500#.
trailer_tongue.jpg
 
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OhioDeere

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NOt clear on what material? aluminum or steel?
I make steel, so I know a little. Aluminum uses same rules.
Some basic rules to follow.. If you are wanting good results and maximum strength of the given material.
As with all welding. always keep your weld length joints as short as possible. always keep welded areas as little as possible.
Virgin material is always stronger than welded joints. Welding will introduce stresses in the materials that is deducted from the overall strength of material, unless properly stress relieved with heat after welded. The actual welds are stronger than the virgin material. The area along the weld "heat effected zone" may have issues which are acceptable for strength if welded correctly. Virgin materials good for welding are annealed heat treated initially. Once major heat is introduced they are not in annealed state anymore. Good weld practices should be followed for the type of material being used. Always know exaclty what material is being welded.

Short welds keep heat in the material to minimal which could introduce unwanted effects. Heat will have warping issues in the structure which may not return to dimension if not welded correctly.
A good welder (person) will know how to treat the material and weld it correctly.

A trailer tongue should be welded correctly given the liablility at stake. And the fact that the materials that are used are kept at a minimal for weight reasons.
 
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T_C,

For duplicating the existing tongue, you have the measurements. I would cut the pieces on a 15 degree angle and rotate the middle piece. For the 4.25" rise, the length of the middle piece needs to be 8.5" (+/-). This is the 4.25" divided by the sine of 30 degrees.

Neal
 
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