I finished up mounting the utility rails (superstrut or unistrut $20 for 10') on the back wall of the bed. I wanted to retain the use of the OEM holes for tie downs so I drilled 4 1" holes above them on the flat section of the bed. I used a 1" hole saw to cut through the bedliner and sheet metal then sprayed the expose metal with rust inhibiting enamel.
To mount the rails to the bed I used 3/8" x6" toggle bolts ($1.98/ea). Unfortunately all I could find were 6" long bolts so I used and angle grinder with a cutoff wheel to cut 3"+ off the ends of the bolts. Each toggle bolt was only $1.98 so while wasteful at least it didn't cost a lot. I used black zinc washers between the bolt heads and the rail. Later I can brush paint the bolt heads black as well if desired.
I drilled the 1" hole on one side of the bed and mounted 1 side and snugged the toggle bolt up just enough so that I could put a bubble level on the rail and mark the next 3 holes. Be sure to compensate for the lean of the truck. My driveway is slanted a little down to the drivers side so I put the level on the top of the bed (below the window) and noted the bubble placement and made sure the bubble was in the same location for the rail. I then loosened the mounting toggle bolt so the rail moved far enough away from the bedwall so I could get the remaining toggle bolts screwed together.
I cut the rail a little too long so if you're dumb like me, make sure to slide the washers into the rail slot before you get the rail lined up and ready to bolt in. ;)
Install the bolts through the washers and then the toggle clamps. You only need to get them started so a few threads is all that is needed. Be sure you have the clamps pointed in the right direction! Then bring the rail up to the holes and push the clamps through starting closest to the pre-installed toggle bolt. Then work your way to the other end.
Tighten the toggle bolts to just before snug. Grab your bubble level and adjust for level as you tighten the bolts.
I am going to try out the 3/8" spring-loaded spring nuts available at Home Depot ($5 pack of 4) or wherever you purchased your Superstrut/Unistrut. I bought a few brackets ($2 - $4 each) to try out but they were only available with 1/2" holes so I need to use a washer with 3/8" bolts. I'll likely return the brackets and get something a little thinner and for 3/8" holes. These 1/2" brackets are overkill in terms of thickness.
The spring nuts are cool because they keep tension on the bolt and are cut in such a way that you can insert them into the rail anywhere (doesn't have to go in through ends) but they will only spin a 1/4 turn or so before the angled ends strike top and bottom of the rail and wedge themselves in place. Pretty cool!
The mount feels pretty sturdy so I'm happy with it. You could easily use a different set of bolts and plastic star nuts to mount something like Maxtrax or Rotopax on there. I also see some possible options for mounting rails on my bed rack to mount gear on the inside of the rack and above the bed floor like fishing rods, more Rotopax or whatever your creative mind could come up with. :)
Like this.
Or this but on the bottom side of the rack (couldn't hold it on the bottom side and take a photo)
