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I just pickup some 2x4 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 2x4.

The server rack I am going to mount on has a backing plate hook which is secured to the 2x4 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 2x4 hold those weight? I am thinking add 2 triangle shelf bracket on the bottom.

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    Totally strong enough it is screwed to 3studs – Kris Mar 19 at 14:52
  • I've done almost the exact same thing, and the 2x4's are strong enough for sure. You did a great job bolting them in. However, 150lbs is A LOT, and I would be worried about the bracket it comes with. See if that has a rating. – JPhi1618 Mar 19 at 14:55
  • Thanks Kris, is the 35" 2x4 itself strong enough if I do loaded the rack with 150lb of weight? – Jack Mar 19 at 14:57
  • I'd be more concerned about the four 1/4" lag screws. What kind of screws? How long are they? Ideally they should be long enough to go through the 2" x 4" - i.e., 1-1/2" long. – manassehkatz Mar 19 at 14:59
  • the lag screws I used to secure the bracket was from home depot was 1/4" diameter, length is 3", same type of lag screws as the one going into studs – Jack Mar 19 at 15:35
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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.

  • Hi isherwood, thanks so much for the pointer. First time home owner since Sept 2018. I did drill the pilot hole for the lag screws, both for the 2x4 and the stud. I never thought about 2x6, but I will give a go, but do you think pull out the lag screws and reinstalling it will weaken the bite in any way if I reused the same diameter screws? The washer is also something I didn't think about, thank you for that! – Jack Mar 19 at 15:18
  • It won't weaken the bite unless you tightened so much that they began to strip (tearing the wood fibers). From the photos that doesn't seem to have happened. – isherwood Mar 19 at 15:24
  • I'd consider going to 5/6" or even 3/8" screws. Holding power is a function of thread area, which increases exponentially with diameter. You can often undersize washers--a 1/4" washer for a 5/16" screw--to reduce countersink size. – isherwood Mar 19 at 15:27
  • I also though about the countersink size, Only have the forstner bit size big enough (too big) that could accommodate my wrench socket size, else it would be too small :( Is it fine to screw the 5/6 into the 1/4, should be no problem right. I kept worrying about having weak bite for reinstalling anything in wood. Thanks again! – Jack Mar 19 at 15:32
  • Hi isherwood, what kind of 2x6 should I buy in homedepot? – Jack Mar 19 at 15:39

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