I just pickup some 2×4 from home depot, not exactly know what kind of lumber, and cut it about 35" , secured to the 3 studs with 1/4" X 3-1/2" lag screws with 2 on each stud (top-bottom). The lag screws has only about 1" of bite into the stud through the 2×4.
The server rack I am going to mount on has a backing plate hook which is secured to the 2×4 only with four 1/4" x 3" lag screws, the bottom is not secured to anything, the total weight I going to put in is around 150 lbs.
Drilled pilot hole for all screws going into wood.
Would the 2×4 hold those weight? I am thinking add 2 triangle shelf bracket on the bottom.
Glue and screw the ship lap together but don't glue the long rails. This will be strong but allow you to disassemble the frame into manageable pieces. I also think you should consider adding cleats to your ladder rungs to keep them sturdy. Cheers!
Best Answer
You're asking about the 2x4. The issue is the fasteners. You won't break the lumber.
You didn't say whether you piloted to the lag screws, but assuming that you did not, or that you did so properly, they should hold well. That said, I'd have probably either used a 2x6 or a small sheet of 3/4" plywood. My reasoning is that a 2x4 is narrow enough and thick enough that it tends to roll. There's a lot of leverage (torque, really) being generated. A taller and/or thinner backer board would have less leverage affecting it.
The same is true of the screws used to mount the server rack bracket. Pilot properly (slightly smaller than the screw shaft diameter--not the thread diameter) to be sure they don't pull out. Pine is soft.
Also make sure that everything pulls snugly together. Gaps lead to movement, which amplifies pullout forces by transitioning them from shear to tension.
Finally, your carpentry looks good, but a hex screw in wood should almost always have a washer behind it. This prevents damage when tightening and increases load distribution. If you have those lags tight enough they'll pull into the wood somewhat.