New Trailer Coming Soon...

StuInTokyo

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#1
I knew that the trailer I'm using had some cracks in it, yesterday I did a delivery I do every six to eight weeks, a bunch of sake over to Gokokuji and back. Not that far, but with a combined weight of about 80Kg between the sake and the trailer it's a bit of a hike. On the return leg, with much less weight in the trailer I notices some tell tale squeaking, this for sure means the cracks have gotten worse.

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You can see the areas that the trailer cracked, I knew it would crack here eventually, this area is kind of a weak link :eek:uch:

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This is the crack in the left side, it is not all the way through the square tubing, close but not quite all the way.

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This is the right side, yep, that is busted!

What I'll do for now is clean the paint off and then weld it some, adding even more metal to this already heavy trailer, its about 34Kg now.

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You can see the extra metal on the right, the Blue "A" point, that is from where I hacked the trailer into three parts to make it wider to fit more stuff that I have to take on deliveries. I'll add another piece of flat steel between the Blue points "A" and "B" where the yellow arrow is on both sides, that should be good to go for another six months. In the mean time, I'm going to start getting things together to build a whole new trailer.

This time I'm going to build it out of round Chromoly 4130 tubing. I'll buy one of these hydraulic tube benders, so I can eliminate as many corner joints as possible. I'll have to get a hole saw sized to the tubing as well, to be able to fish mouth the joints.

I'll get Tim to build me some bullet proof 26" wheels, with disc brakes so I have my parking brake, can't be without that, and the whole deal should be a LOT lighter than the 34Kg I have now, and with some thoughtful engineering, I hope it hangs together longer too!

Does anyone have a source for some good seamless round 4130 Chromoly tubing?
 

GSAstuto

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#4
I used to see this kind of crack failure all the time on stuff we built for the woods. Right angle joints without gussets will have a very high stress riser at the joint and tend to break just there. You gotta either gusset the crap out of it or over build it , or re-engineer to distribute the stress along the length of the strut. Yeah, probably using some 4130 seamless tubing for the cage assy will be a big help. And then perhaps some kind of isolation joint for the toungue? Maybe bolt on with a hard rubber joint? something to dampen out the 'tweaks' and constant working.
 

StuInTokyo

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#7
I used to see this kind of crack failure all the time on stuff we built for the woods. Right angle joints without gussets will have a very high stress riser at the joint and tend to break just there. You gotta either gusset the crap out of it or over build it , or re-engineer to distribute the stress along the length of the strut. Yeah, probably using some 4130 seamless tubing for the cage assy will be a big help. And then perhaps some kind of isolation joint for the toungue? Maybe bolt on with a hard rubber joint? something to dampen out the 'tweaks' and constant working.
The bolt on tongue is certainly a good place to start, that would make a lot of difference :D
 

StuInTokyo

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#9
Cant wait to see the progress Stu!
If you need a farm in the mountains to send yer old trailer, I know of one:rolleyes:
I could definitely incorporate that into my daily chores on the dairy
You sir have a deal, you'll have to make your own hitch, but if you copy the one I built it will not be difficult, as I've done all the R&D :D

Honestly I was thinking what would I do with the old trailer :cool:
 

StuInTokyo

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#11
Cool I have a welder I can use,
Let me know when to pick it up!
You bet, but it will not be soon, but it will happen.

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First project in the new welding space.



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GSAstuto said:
..........You gotta either gusset the crap out of it or over build it , or re-engineer to distribute the stress along the length of the strut......
Well Tim, do you think that will help? :D

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The welding is a bit messy, mainly because I'm using 100% CO2 as my gas, it makes a lot of splatter.

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Top side

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and of course, I had no red paint :rolleyes:

Oh well.

This should hold up until I get the new trailer built.

Cheers!
 

GSAstuto

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#12
The gussets look much better. Make sure you taper them right down! What I experienced (and saw alot) is that you'll get the cracking right at the finishline of the weld, so it's imprtant to dress those. You want the gusset to progressively transfer strain with as minimal of stress risers (concentration points) as possible. Anywhere there is a sharp edge, the energy will be increased there. But , yep - when you get started on the new trailer I'm sure it will be great!
 

StuInTokyo

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#13
A buddy on a woodworking forum suggested that maybe I look into making a set up on my trailer like the hydraulic surge brakes used on car trailers, might work well with the modern hydraulic bicycle brakes....?

Thoughts?