1/4t lunette assembly pictures?

Is there a reason to mount the lunette above the frame of the trailer? Our is inline just fine?

Ideally I'll find a straight lunette and be able to make the mount so that it is inline with the tongue of my trailer. Otherwise one of the bent lunettes could be made to work with a mount that puts the tapered hole above the tongue.

One thing that I've yet to sort out about pintles and lunettes is if there is only one size or more than one. I see lunettes listed with 2.5" and 3" ID holes, but nothing is said about the pintles. Do they come with hooks of specific different sizes? If the pintle & lunette physically go together I would imagine that they'll work so long as the load ratings are appropriate, but are there any rules or guidelines about this? At some particular pintle weight rating do you have to have one of the 3" lunettes because the hook is too big for a 2.5" lunette to work right?

The one pictured is for a M101A1, and the lunette does rotate. These were designed to be pulled behind the M37, M561 series trucks, which both had a fixed pintles and the M35 series if needed. The lunette ring would flip over to maintain a level tongue when being switched from one type of prime mover to the other. When the M37's were retired, and the CUCV was fully integrated, the M101A1 was made obsolete, but still kept in service, as it still functioned fine behind the Chevy and Dodges. Shortly thereafter the M101A2 was introduced to match the CUCV series trucks. This also marked the introduction of the surge brake assemblies, as after the 1980's the Military (the army specifically) required rotating pintles on all prime-movers, to include the designated trucks for the A2 and A3. This is why the A1's have 5-lug split rings, A2 has 8-lug that matches the CUCV, and the A3 has the wider axle and 8-lug to match the HMMWV. Like many of us, the military likes to keep the trailer and designated prime mover with the same wheels/tires (emergency spares) and the same track width (less chance for mine strikes, and makes intel gathering more difficult).

You should have no issue with the load rating on the pictured M101A1, as the trailers are rated at 3/4t. I have personally towed MUCH more than that in an M101A1 and A2's throughout my history. Somewhere I have a pic of my M101A2 loaded with ~60 spools of C-Wire, and the team's gear. The trailer looked like something the Clamppets would have been dragging.

The various ratings for the lunette hole, is the tapered nature of the thing. I have the lunette ring from my Jap T-73 mounted into my M416 lunette without issue. I sat it next to an M100 lunette, and it was a perfect mirror. The 1/4t lunette rings are all the same, between M100, M416, M101cdn, T-73jp, M762. I am sure there are more out there, as the design was used by a number of nations after we left our M100's all over the globe in '44/'45.

The early MBT Willys and BT3 Bantam 1/4 ton trailers during WWII used a different lunette than later M100 and M416. The M100 was a change from the earlier 1/4 ton started in the early fifties. It was the Bantam BT3 and Willys MBT (plus I understand a few other manufactors who made them in small numbers) that were left all over the world after WWII.

Living in the Past said:

The early MBT Willys and BT3 Bantam 1/4 ton trailers during WWII used a different lunette than later M100 and M416. The M100 was a change from the earlier 1/4 ton started in the early fifties. It was the Bantam BT3 and Willys MBT (plus I understand a few other manufactors who made them in small numbers) that were left all over the world after WWII.

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Then I stand corrected. I wonder if the surplus of M100's dumped in Japan after '53 were the basis for the Type-73.

Corprin said:

The one pictured is for a M101A1, and the lunette does rotate.........

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Seeking clarification; rotates in 180* increments, or is free to rotate as the trailer "articulates"?
From the flats on the lunette's shoulder and what appears to be a lug that engages them adjacent to the tapered hole in the casting I'd have to guess that 180* incremental rotation is the operative, but the pictures so far aren't great for discerning this.

You can loosen it and rotate 180 degrees and tighten the nut. It does not rotate once the nut is tighten. Like Corprin stated this was just to have it trailer level behind different military vehicles.

Corprin said:

Then I stand corrected. I wonder if the surplus of M100's dumped in Japan after '53 were the basis for the Type-73.

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That would make sense. Not sure how many WWII trailers would have been brought in after WWII. But during the Korean War Japan was used as a staging area. Would make sense since this was during a time we were trying to help rebuild Japan including limited military.

Just to bad we couldn't have figured a way to get more of the Type-73 trailers over here. Like a lot of things the Japanese took our design and improved on it.

Living in the Past said:

You can loosen it and rotate 180 degrees and tighten the nut. It does not rotate once the nut is tighten. Like Corprin stated this was just to have it trailer level behind different military vehicles.

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hum, then this version of the assembly does not do what I'm after. Which is to allow the trailer to "articulate" beyond the limits of the coupling itself, but with some resistance in that rotation so that the trailer can't just flop on it's side willy-nilly.

Just a long over-due update. I ended up building this:



For sense of scale, those are 9/16" dia. X 7" long bolts. There is a Bellville washer and two bronze thrust washer in the stack of bits on the lunette's shank. By changing the tension on the big nut I can change how easily the lunette rotates. Right now you need a 2' long lever to have any hope of twisting it.

Kind of reminds me of some mystical symbol from a film noir..the Maltese Lunette?

It's my version of the band's monolith in Spinal Tap.

Survived it's maiden voyage on the front of the trailer out to KOH. Driver said that he couldn't hear it at all, but then a 40 series FM on a Tundy isn't quiet....
Previously I built a tow bar for my '84 Xcab that uses this lunette and about a month ago towed it out to the Calico Mtns with the CTD. Heard it make a tiny bit of noise going up Mule Cyn Rd. (dirt), but don't recall ever hearing it on the pavement.