Fiberglass M416/M100 Military-style Trailer Tub Kit

[jscherb]

Back to the covered wagon project, I picked up some eye ends and deck hinges to make the braces for the main bows. I won't know the final length until I begin assembling the frame to fit the tub, and I haven't decided on the final configuration yet. Here's one bow brace mocked up for now.

I've used deck hinges at both ends of the brace. On the upper end of the brace, the deck hinge would be bolted to the vertical part of the main bow. Since the bow is tubing and the deck hinge has a flat bottom, I made up a saddle so it'll bolt up nice and secure. For the mockup it's held in place with a clamp.

At the tub end, a quick-release ball lock pin will replace the screw that holds the brace in the deck hinge. The pin laying on the floor is a bit long, it's just one I had on hand.

Pulling the pin allows the brace to be moved out of the way for access to the inside of the tub from the side. There's a hook clamped to the center bow to hold the brace in the up position. The hook is a one-hole conduit clamp.

 

[Mashurst]

How did you bend the hoops so nice? Did you make a jig of some kind or do you just have mad skilz with a conduit bender?

 

[jscherb]

How did you bend the hoops so nice? Did you make a jig of some kind or do you just have mad skilz with a conduit bender?

All of the bends were done with a simple conduit bender. The sharp radii at the corners were bent using the tool in the ordinary way. The wide radii were bent by hand - I clamped the tool in a vise with the curved side up, placed the conduit on top of the tool and pushed down about 18" from the tool on each side by hand. But moving the center of where I was bending along the curve, and regularly comparing the resulting shape to a curve I had drawn on a large piece of cardboard, it wasn't hard to get all three bends very close in shape.

 

[jscherb]

I made up a base frame for the covered wagon top today. The frame will sit on top of the tub, and will have weatherstrip on the bottom to seal to the tub.

The frame will be secured to the tub using the same lift-off hinges and latches that I used with the fiberglass hard cover/tent platform, so it will install in a minute and won't require drilling the tub for any additional hardware. The hinges can be seen in this photo; they're lift-off style like Jeep doors, so the hard cover will lift off and the covered wagon frame will slip into the same hinges:

Because I'm attaching the frame with the same hardware as the hard cover, it will also be possible to open the entire cover like this one:

The bottom of the canvas will be secured around the frame with snaps, so no new holes have to be made in the tub for them.

There will also be a "drawbridge" piece across the tailgate opening (I haven't cut that out of the frame yet); it will be hinged on one end and latched on the other. It will serve as a location for snaps across the tailgate opening; it will also provide a weather seal for the tailgate, and it will add rigidity when the entire cover is hinged as above. Because it'll be hinged/latched, it will easily move out of the way of the tailgate opening when necessary for loading/unloading the trailer.

Next I'll set this on top of the trailer so I can decide how tall the bows should be, and then I'll be able to finalize the braces. I think it's about a foot taller than I want it to be, but I'll decide on that once I set it on the tub.

 

[jscherb]

It's finally warm enough to work outside, so I tested the bow assembly on the trailer this morning. I posed it with the Jeep so I can get the height of the bows correct - I think I want them just lower than the hardtop. They're about a foot too high, which is what I expected. I made each bow out of a complete 10' piece of conduit, so I expected them to be too high.

A better view of the frame. I'll mount hinges to the frame to mate up with the hinges on the tub, and latches on the other side.

The plan to mount the frame using the existing hinges and latches was originally just to avoid having to drill any new holes in the tub - I didn't think opening the entire covered wagon top would be useful, but now I'm thinking it could be a very useful feature. Here's a test.

Now on to cutting the bows down to size.

 

[jscherb]

I've trimmed a foot off the bows so they're slightly lower than the Jeep hardtop. This is probably the height I'll go with.

 

[jscherb]

This isn't the fabric I'll sew the cover out of but I had a Harbor Freight camo tarp here that's just about the right size, so here's a mockup...

 

[jscherb]

I finished up the bracing for the covered wagon bows. There are no braces on the center bow; that one will be fine with the canvas attached.

For easy access from the side of the tub, the pin can be pulled from the lower end of each brace and there are hooks on the center bow so the brace can be placed up out of the way. One brace is lifted in this photo:

The way I've done the bows it will be easy to remove the cover and store it - pull the pins from the bottom ends of the 4 braces, lift the bows out of the bow sockets with the canvas attached, and it will "accordion" to store fairly flat. Then the frame can be removed because it's just latches and lift-off hinges, and that's pretty flat for storage too.

Next I've got to finish up the hardware that attaches the frame to the top of the tub. I'll be making upper halves for the hinges that will mate with the lower halves that are already on the tub, as well as latches on the other side which will mate with the catches the are on that side of the tub. And I've got to do the removable section of the frame for the tailgate opening, so a bit more to do to call the frame and bows complete.

 

[jscherb]

With the exception of the opening across the tailgate, I finished up the construction of the covered wagon frame today (or as my wife calls it, the "Prairie Schooner"). Hinges and latches are installed. I made the hinges and latches flush with the outside of the frame so the canvas doesn't have to bulge out over them - I'm planning to do a very tightly tailored canvas.

In these photos I've got it propped open with a stick, but I probably should do a prop rod with hooks on each end to prevent a gust of wind from knocking it over when it's open.

 

[woytovich]

I can't wait to see how it behaves at 70mph on the highway! I have one like this (not nearly as slick) drawn up. I started to mock it up using Home Depot conduit! This is going to be sweet....

 

[jscherb]

I can't wait to see how it behaves at 70mph on the highway! I have one like this (not nearly as slick) drawn up. I started to mock it up using Home Depot conduit! This is going to be sweet....

Mine is pretty much all conduit and other hardware store stuff, with the exception of the fittings at the ends of the diagonal braces (boat store stuff), and part of the latches (RV store parts).

I don't expect any problems with it at speed. With the diagonal braces, the bow assembly is as rigid as that on a Wrangler soft top, and I plan to tailor the canvas to fit as tightly as a Jeep soft top. And speaking of Jeep soft tops, I'm considering attaching the canvas to the tub with a plastic retainer strip that's the same as the strip that attaches the bottom of the Jeep soft top. I used that technique on the tilt-up camper top I sewed for my Jeep-tub camper, and it worked out great. It's very strong, and it provides a complete seal so air at speed can't get into the canvas. The photos below show a sample I sewed when I was doing the tilt-up, and the completed tilt-up.

 

[woytovich]

Jeeps have windshields..... this trailer does not have the benefit of that solid full height section that takes the majority of the force of the wind... I look forward to the real world testing.

 

[jscherb]

Jeeps have windshields..... this trailer does not have the benefit of that solid full height section that takes the majority of the force of the wind... I look forward to the real world testing.

True, but a trailer has a tow vehicle in front of it to deflect the full force of the wind.

 

[woytovich]

I REALLY hope it works out well... I'd love one of these for my M416....

 

[jscherb]

Details...

My design for the covered wagon canvas is for it to attach to the wooden frame with snaps. I've also mounted the hinges and latches to that frame to attach the frame to the tub, but in order to get a nice flat surface for the canvas to snap to, I needed to recess the hardware a bit.

In photo 1 below, it was easy to make the hinges flush with the edge of the frame, I just made a recess in the edge of the frame.

Photo 2 was taken back when I was assembling the fiberglass hard cover/tent platform for the trailer and shows the latches I used. They're pretty large and stick out quite a bit from the surface. I wanted to use the same latches to take advantage of the catch already in place on the tub, but didn't want to have the canvas have to bulge around the big catches to snap in place, but as they were, there was no way these latches could be made flush.

Photos 3 and 4 show my solution. I used the hand and adjuster screw from the original style latches so they mate with the catches that are already on the tub and are adjustable, and I modified them to be part of a standard heavy-duty draw latch from the hardware store. They latch very securely, and go through a recess in the frame so they're flush with the outside of the frame so the canvas will be able to snap over them just fine.

Now I've got a flat surface all around to snap the canvas to so it should be possible to make it weathertight.