OBS F350 aluminum topper & Phase 1 & 2 exo cage from lumber rack

Lumber Rack

Started sourcing major components by finding an uncommon Rack-It long bed lumber rack, specifically designed with additional width to fit over a truck topper (also known as a camper shell).

One popped up locally on FB marketplace, and I jumped on it despite the upper tubes being mangled and sitting in a field of weeds.

It was originally designed for a crew cab long bed truck, so while cutting/welding/straightening the upper 1″ tube of the lumber rack, I also lopped off 3 feet from the cab-over extension to match my single cab’s length.

Then, instead of reusing the forward section of 2″ OD tubing, I bridged the cut with a lower profile 1″ OD tube to reduce frontal area.

The lumber rack had large, 5/16″ thick footer plates intended to bolt to the top surface of the bedsides, so I trimmed them down to roughly 2″ wide to match the OD of the upright tubing, and welded and bolted them to my bed rails, which are capped and framed with angle iron.

Then, positioned the rack uprights at the very forward edge of the box to form a headache rack and halo over the cab.

Ran the rack for the time being with the fullwidth 2′ thick Weatherguard toolbox, while on the hunt for a topper.

Topper / Camper Shell

Craigslist saved search with keywords: long bed + topper, produced a local hit for a used, aluminum contractor unit, with a single passenger-side flip-up panel, and rear swing-out double doors.

Jumped on it right away because the seller had it on a likewise long bed OBS Ford pickup, so no questions about fitment. Pulled off the toolbox and tailgate, brought along c-clamps and straps, and did the deal.

For reference, the following fullsize 8′ long bed topper accessories are compatible with an OBS Ford pickup:

  • 67-96 Ford 8′ beds, 97 F250HD and F350 8′ bed
  • 73-87 GM 8′ beds and up to 91 3500 8′ bed
  • 72-93 Dodge 8′ beds

Also for reference, the following long bed topper accessories are NOT compatible:

  • 97-newer F150
  • 99-newer Ford Superduty
  • 94-newer Dodge (due to subtle dovetail and narrower rear box width)
  • 88-newer GM

Upon taking delivery of the aluminum topper, was surprised by how lightweight the unit is even with doors and panel attached. It slid right into place.

Topper / Camper Shell build out

The topper is constructed of 1×1″ square aluminum skeleton ribs, skinned with painted aluminum sheet, and interior lined with thin speaker box carpet.

Once home, took the opportunity to cut and apply thick neoprene strips (intended to line a toolbox) between the bedrails and shell, then bolted it down with a dozen M8 fasteners.

The topper also has a dual slider window for access to the cab, but my single cab has fixed glass and something to address in case of emergency or to access the cab from inside the camper, which cannot be locked from the inside, nor can it be opened from the inside if latched closed from the outside.

With the tight fitting lumber rack, i had a vision to add triangulated tubes and build an exo cage around the shell.

With several 20′ sticks of 1.75″ OD, 0.120″ wall HREW steel tubing left over from a Jeep build, and an Affordable Bender (Model ab105 with 1.75″ mandrels @7″ bend radius up to 90*), started on the asymmetrical exo cage first on the driver’s side with no opening panel.

Phase 1 Exo Cage Build

Started cutting full length rock slider tubes spanning front and rear wheel wells.

Kinked slightly with an apex between the cab and bed to follow the body lines and transition between cab and body.

Next, cut and notched another tube to tie the slider to the truck frame.

Then, a vertical tube with multiple kinks to follow the bedside while continuing the line of the halo down to the slider tube.

Lastly, added triangulated tubes from the mounting point nodes to the upper longitudinal tube on the driver’s side.

The cage is intended to be asymmetric right/left, by creating a tube node further back that center to support the rear crossbar that is still the pinned, removeable piece as opposed to notched and welded.

When bending and positioning the HREW, the welded seam is put towards where it will likely make contact with rocks and obstacles, and should be tougher to dent than plain wall; otherwise, bends are clocked 90* from the seam as to not stretch or buckle the weld. Again, all tube bends shown here done with a manual hydraulic bottle jack in an Affordable Bender (Model ab105 with 1.75″ mandrels @7″ bend radius up to 90*) .

Phase 2

Tube along the rear quarter fenders tied to the rear bumper, and cage nodes.

I went with a triangulated tube in the front, to tie the far end of the rock sider along the body. It is right up to where the fender flare line starts.

needs mudflaps

Then another vertical tube from the rear pillar in the cage, to continue the line from the rack. It is terminated with a tube along the rear quarter panel, and welded to the rear bumper.

Crossbar spanning the rear of the rack is removeable with a pair of pins. There’s a rolled up awning bolted to the bar with fold out legs that can make a shade or rain cover.

Published by Manolo al Sol

Learning by adventure.. will curiosity kill the cat ?

4 thoughts on “OBS F350 aluminum topper & Phase 1 & 2 exo cage from lumber rack

  1. No, the shell on the OBS Ford came off another OBS. See my post here about finding the ARE topper: https://manoloalsol.com/2020/12/07/f350-aluminum-topper-exo-cage-from-lumber-rack/

    What i meant is the Ford OBS tailgate is wider than the 2nd gen Dodge, so when i replaced my OBS with Dodge, i could not use the ARE topper which replaces the tailgate, and had to find another one for the Dodge which has a slightly dovetailed bed, narrower than the Ford.


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