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Tudor,

OK - the lights just went on (i.e. I get it). Makes sense now. For the most part it's the lateral loads and lack of taper bearings for locating the hub that exclude these trailers from being rated highway worthy (of course tire ratings, lights, etc also influence this also).

I've encountered problems due to lateral loads with the bushing style hubs on my 4 wheel Agri-Junk stamped steel lawn/garden wagons. The hub/wheels on these trailers are located laterally on the spindles (both inside and out) with washers and cotter pins. I have had the inner cotter pins break allowing the wheels to move inward to the point of rubbing through the tire sidewalls against the steering arms. Turning at slow speeds under load apparently places a lot of lateral force on them.

I'm guessing that this problem is more pronounced on four wheel wagons than on two wheel trailers. Since (when turning) the two independent wheels allow the trailer to pivot easily lateral loads at the hubs would be minimized.

Thanks for the primer in bearing designs and characteristics. The information will be helpful in the future for comparing or building a trailer or wagon.

JN
 

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Discussion Starter #22
OK, time for a update.

I did contact CMI about my issues. They are going to credit me $100.00 for the bad paint and boards that I had to replace.

I voiced my concern about the bearings and axles. They told me that:

" they would last forever as long as I was diligent about keeping them greased. The only people that have bearing issues are the ones that do not regularly grease them or operate the trailer at higher speeds. The bearings will wear out before you see any wear on the soft shafts"

Interesting, I hope that I am proven wrong about the axles.

I have really been giving the trailer a workout today and tomorrow. Over the weekend I plan on pulling the wheels and look at the bearings and axles.

The hydraulic dump works great. It tilts up plenty high so that nothing is left inside to scrape out. Maybe if you had soft sticky clay, it could be an issue.


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Discussion Starter #23
I moved 20 tons of chert this weekend and the trailer worked out good. Eventually I will change the sliding back gate to a swing style for better dump and run control. I did manage to get one flat tire, plugged it and continued hauling.

Since I had the tire off for plugging, I was able to inspect the soft axle for wear. The bottom of the axle showed some polishing but no grooves were present. I greased the axles twice a day to help keep out any grit since there are no seals.


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Thanks for your post. I just purchased one of these and hope some of the workmanship issues have been resoloved.

I am curious why you chose a 4" cylinder over say a cheaper 2" or 3". Were you able to calculate the needed size based on the 2 ton capacity?

Thanks in advance.
 

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Thanks for your post. I just purchased one of these and hope some of the workmanship issues have been resoloved.

I am curious why you chose a 4" cylinder over say a cheaper 2" or 3". Were you able to calculate the needed size based on the 2 ton capacity?

Thanks in advance.
Geometry. Due to the low angle between the cylinder centerline and the bottom of the dump box, less than 25% of the available force from the cylinder is actually available for starting the lifting process. For a 2 ton payload with a 4" cylinder, the hydraulic pressure requirement is over 1400 psi. That does not include the weight of the dump box or any excess payload.

A 2" cylinder would require 4X the pressure, and a 3" cylinder, almost 2X the pressure. Both are beyond the typical capabilities of the normal on board tractor hydraulic systems. A 3.5" cylinder will just barely work for some tractors, and require 1.5X the pressure, but any overload is going to give problems at the start of the lift.

Not many people have a weigh scale available to check the payload weight. Most just load the trailer to capacity without spillage and call it full.

A 4'x8' bed with 16.5" side walls has a struck capacity of 44 cu- ft. Dirt weighs approximately 90 lb per cu-ft, and gravel up to 135 lb per cu-ft. Do the math.
 

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The photos seems to show 2 hoses which suggests a double acting cylinder. I was wondering if a single acting cylinder would work using gravity to return the bed to flat position? I will be hooking this to a Mahindra Max 26 which has a power beyond hose as well an open center arangement (2 hoses normally coupled together except when connected to backhoe).

Also can you suggest what type of control valve I should order for either a power beyond option or open center double acting arangement.

Thanks in advance.

Dave
 

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It is a double acting cylinder. Single acting cylinders are usually a bit more expensive and quite restricted for alternate uses for yard or small farm type operations where the dump trailer use is limited.

Power beyond is a feature of the first valve set in a series of valve sets that allows the fluid to continue downstream while reserving an alternate flow path back to the reservoir for fluid going over the relief valve. As an example, your loader valve set will have the power beyond feature so that additional valve sets (eg. the back hoe) can be added without worry that additive pressures from use of the back hoe and loader at the same time will destroy the pump.

In your case, the quick connects are used to insert the second valve set into the circuit the same as the back hoe valve set is inserted. Alternatively, for a permanent installation of the second valve set, the line from the power beyond port is plumbed directly to the supply port of the second valve set and the quick connects are moved to the return line of the second valve set for the same function that it currently supplies, ie. a place to connect the back hoe.

Any open center valve set for cylinders will suffice. I suggest a 2-spool valve set just because I like the option of an extra work circuit, whether I need it or not.

A dump trailer is usually connected to the hydraulics at the rear of the tractor, and there are back blades available that can also use hydraulic connections at the rear to angle them left and right, as well as tilting the blade for ditching, and extending the blade to one side which allows the tractor to be on level ground while carving the ditch. That's an implement that has a need for a 3-spool valve set.
 

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You could of course, case harden the axles yourself. Just get a good hot charcoal fire going and put the end of the axles in it. Wait until the axles are thoroughly heat soaked and then quench them in a bucket of water. Not a very scientific method, but it sure will be effective.
steve
AH no you cant do it like that. First Case hardening Is done by heating a piece of mild steel to orange then adding a case hardening compound, this hardens the outer skin only. What you speak of as getting it glowing then quenching is hardening and will only work if the steel is a high carbon hardenable type. But then it would have to be tempered after that or it would be brittle. Mild steel cannot be hardened.
 

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AH no you cant do it like that. First Case hardening Is done by heating a piece of mild steel to orange then adding a case hardening compound, this hardens the outer skin only. What you speak of as getting it glowing then quenching is hardening and will only work if the steel is a high carbon hardenable type. But then it would have to be tempered after that or it would be brittle. Mild steel cannot be hardened.
Madmax64, just wanted to point out that you replied to a post that was last active in 2009. You may want to watch the dates of the threads a bit more closely. Also, welcome to MTF!
 
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