4

I am a novice when it comes to working with wood, however I would like to learn more. Please accept my apologies in advance for asking technical questions for such a basic project..... as this is not about the 'art' of woodworking, as much as my understanding of basic principles to follow.

My first project is to build some simple shelving units for my garage using 2x4 softwood construction (not pretty, but meets my utility needs and helps keep the cost low). Plans for 'cheap & easy' garage shelving are readily found all over YouTube and after reviewing too many to count, there seem to be some basic consistencies, such as adding perpendicular bracing underneath the shelf platform (spanning from the front rail of the shelf to the rear rail). I 'assume' these braces are intended to allow for a greater span between the shelving legs, helping to support the intended load and prevent sagging in the middle.

My question relates to this bracing: Some folks merely drive long screws at a 90° angle to construct the shelving, essentially creating a rectangular box for which the shelving material (I am using 7/16th MDF) is placed upon. The perpendicular bracing is then added under the shelf.

"Some" folks out there in YouTube land suggest using pocket-hole screws to join these braces to the shelf rails, instead of relying on the strength of a screw driven into the side of the shelving at 90°. Their argument is that the pocket-hole screws are "stronger" and will help carry the downward load placed upon the shelf.

Q1: Are pocket joints stronger for this application?

Q2: If so, what locations would it make the most sense to use these pocket joints instead of simply driving the screws straight through the rails and into the braces?

enter image description here

Once again, I realize this is a very basic 2x4 project, and I hold woodworkers in high esteem do to the combination of artistic talent and engineering required. I am hoping, if I start my journey into woodworking by understanding some basic principles, this will hopefully help tackle more challenging projects in the future.

5
  • A couple related points to consider: If the shelves are intended to be bins then plywood on the underside is fine, but use screws rather than nails to secure it to the frame. Otherwise plywood on the top will be easier to keep clean...
    – Ashlar
    Nov 13, 2023 at 15:23
  • ... keep the bottom shelf above the garage floor by a couple inches to prevent moisture from deteriorating the wood but allow enough of a gap to allow getting a broom or brush under to clean out dirt once in a while. Use 3/8 or 1/2" sheeting for the surface. Also, while the 2x4 frame around the shelf perimeters is needed, the spreaders at thirds are not unless you are loading the shelves very heavily in which case I would not simply rely on a couple screws to hold the shelves.
    – Ashlar
    Nov 13, 2023 at 15:25
  • Hi, welcome to StackExchange. Since nobody answered your Q1 quite as directly as you might have liked: no, they aren't. There are various complexities (that are covered in some of the below) but for construction of this exact type a screw through the outside into the bracing really can't be beat. Now that said, pocket-hole screws would almost certainly be more than strong enough here. If you have the pocket-hole jig already there's no reason not to go that route for the construction of the shelf boxes, but if you don't then one is not necessary at all for this project.
    – Graphus
    Nov 14, 2023 at 7:48
  • Re. your Q2, isn't that obvious from how you've seen pocket holes drilled in the various videos you've watched? Pocket holes always go at the ends of boards that will be joined to another board at right angles.
    – Graphus
    Nov 14, 2023 at 7:52
  • There's no need to apologize for being a beginner! A pocket screw jig is very nice to have. But for garage shelves using 2x4s I've built several sets of these and recommend: woodgears.ca/shelves/garage.html Nov 14, 2023 at 19:31

3 Answers 3

6

Pocket screws are great when there is no other access (or you don't want the screw heads showing) and gluing with dowels is not an option. But their strength depends a lot on various factors including how you drilled the hold and the screwhead maybe pulling through the pocket.

But this is a first project for a garage, aesthetics don't matter all. So there is no need for pocket joints here.

If you want strength for the shelves, the best thing is to have them rest on something.

The easiest way to do this with a 2x4 construction is creating some stub 2x4 along side the rails and creating pockets for the shelf to rest in. That way the screws into the shelves are there only to hold the shape and the strength of the shelves comes from wood resting on wood. And you have plenty of room attach the supporting bits to the uprights.

If at the end you find that there is some play in the joints then add diagonal bracing to stiffen it up.

2
  • 5
    Agree with one caveat: if the OP is looking for an excuse to buy a pocket screw jig, then absolutely pocket screws are necessary ;)
    – JimmyJames
    Nov 13, 2023 at 21:33
  • Actually, after some thought, I'm not completely joking. This isn't a terrible project for getting some practice with a pocket screw jig when the stakes are low.
    – JimmyJames
    Nov 14, 2023 at 20:55
3

The strength of the screw is in it's shearing strength, generally speaking for construction like this neither is inherently stronger.

If you were worried the strength isn't enough put in another screw! Or alternately, use Nails, nails generally have a much higher shearing capacity than any similarly sized screw.

7
  • Nails are good for horizontal application, as they have higher sheer strength. Screws are better for vertical application as they have better pull-out resistance. However, unless you're storing gold bullion, there's probably enough shear strength in your average box of screws, applied 2-per-joint to not make a practical difference in something like this.
    – FreeMan
    Nov 13, 2023 at 18:34
  • 1
    @FreeMan yes, I agree, though I often use 3 screws, but I was trying to inform. and someone always had the option to do both, a nail and screw, screws don't loosen and nails have great shear strength, but as you pointed out, probably over engineering.
    – bowlturner
    Nov 13, 2023 at 19:49
  • Wasn't meant to be a complaint, I did +1. Just providing more info.
    – FreeMan
    Nov 13, 2023 at 20:53
  • 1
    @FreeMan, nails can no longer be said to have higher sheer strength than screws. Many modern screws are extraordinary in terms of their metallurgy, by comparison to a basic mild steel wood screw (or nail).
    – Graphus
    Nov 14, 2023 at 7:29
  • 1
    @FreeMan I didn't take it as a complaint, just a discussion. :)
    – bowlturner
    Nov 14, 2023 at 14:24
0

As you say, this is a utility need, so seeing the screws on the face of the shelf is ok. Using pocket screws are only for asthetics and would only increase the complexity and time to finish your project.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.