Are all A frame couplers 50 degree?

[G-force]

Anyone seen one wider? I am building my frame right now, want to use an A frame or composit tounge arangment, but I want my A frame members to extend the full width of the trailer (58") and a tounge length around 42" which puts my A frame angele around 71 deg if my trig is correct. I had originaly planned for a composit style and extending the center tounge enough to use a standard coupler designed for 2" tube, however I like the more traditional look and mechanics of having the nose jack fixed and centered in the V nose coupler. I have a swing away Fulton Jack on my utility trailer, and while it performs, its is ugly. Perhaps I need to find someone with dies and a bender large enough to bent the last 12" of my A frame members inward 10.5 degrees to make the 50 deg couplers fit nice.

Mike

[doug hodder]

Mike...it's just an idea...but if you are doing a composite tongue...start the A members just aft of the coupler. If the tongue is stretched a bit, the angle isn't so great and a Fulton swing away jack will work great. It won't be a dead center wheel, but not so far off center that it will be a problem. I've done several like this. Also, Fulton has a short jack that will tuck up really well and allow a tongue box to boot that will clear the wheel. Doug

[madjack]

Mike, in the past, I have notched the tube and bent it to 50*...welded it all up properly with a fish plate and had no problems...
madjack

[angib]

Mike, you seem to be assuming that the A-frame starts tapering in from the front of the main frame, like in the top diagram.

It may do that, but it's much more common for the A-frame to be attached under the main frame and overlapping it for some distance, like in the bottom diagram.



Andrew

[Nitetimes]

I have in the past welded my tongue pieces to the coupler then measured back the frame where I wanted it attached, tacked one side on then squeezed it together to get the other side in position. Works fine and nobody knows you cheated.
I usually only try this trick if it's under 6" too wide tho.

[G-force]

Thanks for the replies, madjacks solution is what I figure is probaly my best best.

Andrew: Your right, I want it like your top drawing, and not have the a frame underslung on the main frame. Partly for looks, partly because it already takes a 6" drop ball mount in my truck for my utility trailer which has a 16" deck height, my tear is going be be lower and I am really trying to keep the coupler up as high as I can without goose necking it.

[madjack]

Mike, the notch fell within the coupler body, a fishplate was added to the inside...the notch, was made with 2 cuts(perside) from a 14" cutoff saw...one would have probably been suffcient............
madjack

[angib]

Mike, no problem - the (50-deg) A-frame can be on the same level, but only reach full width behind the front of the body. This is stronger than the alternative.

Either use just a front cross-member, split so that the A-frame members are continuous as in the top diagram, or fill in the corner as in the bottom diagram - this second one would be more suitable if, say, you were leaving the frame visible. I prefer the first one as the joints are less complex and so are likely to be better welded (good access = good welds).



Andrew

[Alphacarina]

Andrew: Your right, I want it like your top drawing, and not have the a frame underslung on the main frame. Partly for looks, partly because it already takes a 6" drop ball mount in my truck for my utility trailer which has a 16" deck height, my tear is going be be lower and I am really trying to keep the coupler up as high as I can without goose necking it.

The top drawing is the weakest way you could possibly do it

What not make it like the bottom drawing, but run the tongue through the front crossmember instead of under it - It will be stronger that way and you can have the tubes at the conventional 50 degree angle

Don

[brian_bp]

My Boler travel trailer has the design which Don described: the A-frame is in the same plane (and of tubing with the same dimension) as the main frame rails, and pierces the bent sheetmetal front crossmember. This works fine.

On the other hand, other than appearance there is little need for the main rails to go all the way to the front crossmember, especially if the A-frame members are not just joined to the main rails, but are simply extensions of them. I believe that the top drawing of Andrew's two latest options is very efficient, structurally fine as long as the A-frame and main rail members are suitably joined (or are one member, bent), and is the typical structure used in European complete trailer chassis made by companies such as AL-KO and BPW and used by trailer builders. I suspect that's what you'll find if you look under a Tab.

[Trackstriper]

Similar to Brian, I had a 6x12 cargo trailer that had a pierced front cross-member. Alway looked a little shaky, and it never broke. It was simply a folded steel "C" section. But I never liked it.

For my build I'm planning to use an "A" frame tongue in the same plane as the main side rails, but with the front cross-member above the tongue and side rails. Does anyone see a problem with this that I'm maybe blind to? The fourth side of the tongue to side rail weld would be sketchy, hard to access, but is it necessary?



Hope this quick sketch helps...assume 2" square tube. The front cross-member would be behind the front wall of the trailer to hide it.

J.B.

[angib]

The fourth side of the tongue to side rail weld would be sketchy, hard to access, but is it necessary?

I think your plan is excellent and should make a strong trailer that's easy to build - the downside of the pierced or multi-part front cross member isn't structural, it's the difficulty of jigging all the pieces and keeping them straight when welding.

But sadly the vertical welds on that joint are the ones that do all the good - the top and bottom horizontal ones don't do much - so it would be preferable to have the second, awkward weld done well. How about adding a short offcut of tube (2" lengthways and max 15/16" crossways) that enables two better welds to be added, like the red piece below.



(Now you've gone and raised the stakes from 2D to 3D, I've had to do extra work... )

Andrew

[Trackstriper]

Andrew, I follow you on the filler piece. Good idea. I just didn't know if it was a major strength issue. Thanks for the input. Maybe this can also help G-Force with his frame.

Sorry about the cheesy 3D. I just though it would be easier to visualize. So just who's upping the ante...with color yet???

J.B.

[angib]

Here's a nice picture of the sort of frame I was describing somewhere above, with a three-part front cross member part-way along the A-frame.



It's from the new photo album in the Hall of Fame from Dale & Sandy in Australia.

Andrew

[brian_bp]

For my build I'm planning to use an "A" frame tongue in the same plane as the main side rails, but with the front cross-member above the tongue and side rails. Does anyone see a problem with this that I'm maybe blind to?

I can't think of any problems - nice solution! (and nice illustration!)