My first big fabrication - Flatbed for F350

[sticks]

About 2 days after taking delivery of a 2014 F350, the owner decided that he wanted to put a flatbed on it (should have ordered a chassis cab, grrrrrr.) My boss passed the project on to me. 8' x 10', and the headache rack to follow the cab body lines.

With the help of SketchUp 8, I was able to design the entire thing from the frame up. If you do not have a CAD program, I highly recommend Sketchup. Angles, dimentions, 3D view and ability to rotate around to get different views.

Here is the picture I started with to get the general layout


Then I drew up the entire design





Day 1 - lay out the base frame, forgot to get pics before I put the deck on.



Installed the deck and headache rack. The CAD design measurements was awesome. Cut everything to length, angle, etc., laid it out on the bench, verify that it was square and weld it together. Fit perfectly.



Day 2 was finish up the top rack sides, place the 4 tool boxes and make the side and tail plates. I'll get pics of that on Monday.

Next up is the tailgate and bumper/tow hitch receiver.

[Rambozo]

Looks nice. I like your little cutout steps in the rear plate. I love Sketchup, too. You might look around the 3D Warehouse to see if there is a truck model you can use as a starting point for things like this. I'm in the middle of a similar truck project based around an E-450 cutaway, and I was able to grab the cab off an ambulance model to use as a starting point. While it wasn't perfect, it gave me a good idea of how things would work and let me fit a lot of parts on the screen instead of in metal. You can also get pre-made models of a lot of parts from the manufacturer's websites. Things like lights and fittings. Another nice thing about 3D modeling is that with all the dimensions, you know the area for coatings, and the total weight of everything.

Looking forward to seeing your progress and seeing the model become metal.

[sticks]

Looks like my pics are going to end up being a day behind my work.

Here is what I finished up on Day 2.




Yesterday was a short day, top it off I got shifted onto a repair at Noon.

Got the bumper installed, tailgate skinned and test fitted with the hinge, and the reinforcements on the underside (for the sides that wrap around braced to the frame). Mostly happy with the tailgate. The boss wanted it to fold down so the bed was flush (READ - no "bump" from the hinge) so that put the tailgate 5/16" above the bumper when dropped, and the hitch will be 1" lower than OEM.

My Plasma Helper circle cutter that I bought back on the 5th hit a delay in shipping (supposed to be here yesterday) - so I have been holding off on cutting the holes for the lights. The tail skin is only tack welded on right now. Probably won't see the circle cutter until Thurs. So much for "2 day shipping".

Today I should be able to get the hitch receiver mounted and channels for the wiring on the forward overhang (hazard lights) and the under side. Drill the holes for the tool box mountings, and some painting prep work...gonna be a not much accomplished day. Really waiting on getting that tail skin finished. A fair amount of work is waiting on that, and I'd rather cut the holes horizontal, rather than vertical.

[sticks]

Sorry to take so long to update.

Project has been long done, like Dec 18th.

The circle cutter showed up finally, and it is a nice piece of equipment, but it does take some practice to keep the torch flat, not a whole lot of surface to do it. I end up with slightly oval holes. More practice will fix this I am sure. The only improvement that I would make is to use smooth rods for the diameter adjustment with thumb nuts over the threaded rods. Takes a fair amount of time to make adjustments. The only benifit I can see with the threaded rods is fine tuning the diameter/radius by gaugeing the spacing you need to back off one of the nuts to get to your desired point if you are within 1/8".

Anyhow...




First pass with the bumper installed. Waiting to test fit to see if I need to trim off the support.


First test fit. I probably should have done more to support the base frame when I put in the cross ribs. I ended up with a little sag in the middle, which caused me some fits trying to get the mounts installed so the flatbed frame sat flat on the truck frame. I ended up raising the tail up to get the front flat, installed the mounts, then let the back down (a touch tail heavy with no tool boxes) to get the rear mounts set.







Finished and shipped - so to speak, the darn thing is still sitting in the parking lot. Evidently they were not in as much of a hurry to have it as I was led to believe.



This is another part that gave me fits. How to insure that the load on the hitch was transferred to the truck frame rather than the bumper, and still make it removable. We had an olde REESE hitch laying in the parts room that got modified to fit to the bumper, then I had to make a plate that bolted to the OEM receiver mounting points on the frame out of some 3" x 6" x 3/8"" angle, then marry the two with a piece of 3/8" plate, and pray that my drilled holes were dead on. I got lucky. 3/4" bolts, 13/16" holes. Once it was all bolted down to the truck, I welded the middle plate to the hitch. I had my doubts that it would marry back up on the final install, but everything went smooth.


I would have preferred to have been able to "one piece" the tails skin rather than that second 7" piece that I had to weld in, then grind flush. Live and learn.


I'm pleased. Especially since I was able to take my measurements from the CAD, cut and assemble on the bench, and the end result was within 1/8" of desired. Through the hole project, I only had one miss cut, and I was able to re-use it down the road. All of my box tube cuts were done with a chop saw and carbide blade. I ended up making 6 angle templates to make sure that my miter cuts were within 0.5*.

Lessons learned;

More support for the base frame when adding ribs (more weld bend than weight).

When your drawing calls for a 1 piece, make it a one piece.

Even with multiple tack welds to hold a thing, it will still bend when you put your full bead on. Might be a welding skill thing, might need more supports to hold in place then remove when done.

Questions, comments, criticism?

[everlastsupport]

Looks good, nice shop. Got a laugh at "Evidently they were not in as much of a hurry to have it as I was led to believe.". What City and State is NO and WHERE? Oops. I can see Colorado on the door.

[Rambozo]

Looks nice. Typical rush job, hurry up and wait.
You mentioned that one of the design goals was to have the tailgate fold down flush with the bed. It looks like that is when it is folded all the way down. Does it also lock into a flat position like a standard tailgate? And if so it's higher than the bed, right? I have to build a tailgate soon, and I'm looking for ideas. I can't quite tell from the pics, but it looks like the latches are the old school retaining pin type, or something else?
CAD sure can really help for things like this. Make the mistakes on the screen instead of in metal. Compensating for weld distortion is kinda an art in itself. When possible try to have symmetric welds helps. You can also prestress some parts so that when welded they pull straight. Heat straightening parts can really help, too. Jody just did a video with a tip for flanges for a couple of jobs. I'll have to try that sometime, as the large aluminum stands he did were really surprising how flat they came out after a ton of high heat spoolgun work.

[sticks]

Corner of "No" and "Where" is typically where I am at. Middle of nowhere in the state. Open field, closest thing resembling a town is 40 miles. No supplies other than what I brought.

Tailgate folds all the way down, (180*) and is flush. To make it flush with the bed at 90* you need to have a swing out type of hinge point. I'll take a pic of what is on my service truck and post later. When it is all the way down, the tailgate will be lower than the bed.

Tailgate hinge is the simple pin style. No need to lock or latch, just drop a pin. KISS, or they will break it.

[sticks]

Completely spaced taking a pic.

Here is what I meant by the swing out hinge;



With the tailgate closed, it will be flush with the bed walls, and be 1/32"ish above the deck. When open, it will be 1/4"ish away from the bed.

I'm sure there is a math formula to tell you where the pivot point needs to be given the thickness/depth of the tailgate to rotate 90* and be flush with the bed as shown in the pic. Layman's method will be trial and error, and easiest with a mockup.

My boss wanted the tailgate to have a flush bed with the tailgate all the way down, and it is not strong enough to support the amount of weight these guys will put on it if it was held at 90*. I cold have made it stronger, but it would have weighed waaaaayyyy too much. We don't have the tooling to bend sheet metal to build in structural support instead of adding ribs.

If you did not want a surface mount hinge, I'd go look at a pickup - same principle, except that under the tailgate, there will have to be a cut out area.

[Kempy]

NO and WHERE has a book on NO and WHERE

[sticks]

Good photo shop work. Missed the shadows on the banner though.

Might be an actual image you found. Before my time with the company.

[Kempy]

Good photo shop work. Missed the shadows on the banner though.

Might be an actual image you found. Before my time with the company.

This is on the your site: http://www.concreteworksofcolorado.c...y_Handbook.pdf 2008/2009 Handbook

[sticks]

Huh, interesting. I don't spend any time on the company website, in fact I have only been there once, and that was to confirm the address before my job interview, against the verbal driving instructions I received.

[Kempy]

Well like the old saying, you can run but you can't hide we will find you.
Overall you are doing a nice job on the truck.