I'm working on a slide-out system for the bed now. The plan is to have most of my gear in Milwaukee packout containers on one slide, and have the other side be more generic storage for day-to-day stuff and things that aren't practical to fit in packout. The overall goal is to have as close to 100% as possible of my gear rigidly mounted so that nothing is sliding around back there.
I built one of these years ago for my girlfriend's farrier truck and incorporated a few learnings from that project.
High quality blueprints with a cut-list for anyone that wants to steal:
I settled on this design after a few iterations, it has a few benefits.
- Almost zero critical dimensions. I just have to get the frame close to nominal width and have the three longitudinal frame boards parallel, only the backs of those three boards even need to be square. Every other piece could be cut off-square in the dark and it won't matter. This is good because I'm pretty dumb.
- Raising the shelves above the slides lets them take the full width of the bed between the wheel wells
- It also gives extra storage under the shelves for anything less than 5.5" tall (camp chairs, folding tables, rifle cases, etc)
I visited a friend that has a table saw and a good knowledge of woodworking and got all the pieces cut. Then made the steel parts at home and assembled the frame. It's upside down in this photo.
When the slides are pulled out the weight acts as a cantilever against the back of the frame, trying to pull it straight up. That steel strap screws to the back of the frame with 12 GRK #8x2" cabinet screws. I made a test rig with 1 of these screws and hung from it with some weights, about 200lbs total. So that puts the minimum tensile strength of this connection at 2400lbs. I'll use a number of M8 bolts and rivnuts for the bed-side connection that exceed that 2400lbs.
Shear strength of a #8 wood screw is about 2200 lbs, so with 8 of those transfering the load to the sides of the frame (and 3 of the screws in tension tie into the sides as well) I don't see that joint failing. Likely the wood itself will fail first. Those connections are also glued.
Consider worst case scenario is ballpark 500lbs of gear distributed around the slides, fully extended with a 200lb person standing on the end of each one...
The 500lbs distributed is equivalent to 250lbs on the end (I think), so in total that scenario is 650lbs at 60" from the slide front (maximum pull out). The frame is 80" long so we have 3/4 cantilever, for ~490lbs of tension at the back of the frame. That gives me a safety factor of at least 5x. If any of this napkin math is correct. There will also of course be fasteners at the mid and front of the frame (back of the truck) bolting it to the bed.
The slide hardware itself mounts with 10 #14x3/4" stainless fasteners on either side... the shear strength of those is astronomically larger than the loads they'll see.
All that is to say, I think I've engineered this appropriately. Am I missing anything? Time will tell... or you guys will point it out
All of the pieces are stained now with an oil based urethane sealer, will let that cure overnight then continue assembly. Next up is test fitting the frame in the bed and drilling / installing rivnets.
Side note - it's cold as hell here right now. I speak celsius but that's -15f/-33f. Have the propane heater running full blast out in the shop.
