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I have come across a lot of designs and plans for things like outdoor furniture, kids' furniture, etc., that call for the use of pocket holes. I can appreciate why this is enticing to a lot of people as it's a lot simpler that mortise and tenon joints or dovetails while still being concealed.

Matthias Wandel has an article on Testing pocket holes against mortise and tenon and dowel joints where he finds that they are indeed significantly weaker than other joint types.

With the exception of small objects, 99lbs as an average breaking force for a pocket joint doesn't seem very strong at all. I could see a tabletop generate forces beyond this with just a few adults leaning on it.

Are there any times when this is an appropriate joinery technique to use, over alternatives? Or are they just typically used when someone doesn't have the skill, time (or maybe cost) to build a more robust joint?

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    I notice that the pocket holes weren't glued whereas the other were. this would add a lot of strength. He did say that in videos he had watched pf pocket hole joinery, they hadn't been glued either but perhaps they were for applications where that much strength wasn't required. He should at least have tested like-for-like, just to see a fair comparison. – Steve Ives May 8 '15 at 10:14
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    He actually does re-test at the bottom of his article with glue and his conclusion is that it doesn't make them much stronger. – Steven May 8 '15 at 12:55
  • Thanks - I hadn't seen that. However, in another of his tests, he shows that butt-joints simply glued can be quite strong, so concluding that the glue adds no strength to a pocket join is odd. – Steve Ives May 8 '15 at 13:35
  • Well we know glue is as strong or stronger than wood, so I think the point in this case is that all the strength is the glue, the screws being held in the wood will fail before the glue does. So really, adding screws doesn't add strength, not the other way around. – Steven May 8 '15 at 14:17
  • If you follow the link, the problem with the pocket hole joint is that it deforms a lot (beyond the point of acceptability) before failing. If you glue, the glue fails (and the joint deforms a little), but the screws still hold the joint just fine. Then the joint continues to deform, and eventually you have to throw it out. – Martin Bonner Apr 9 '16 at 9:11
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Bear in mind that that 99 lbs is for a single joint with pressure being applied in the manner of a first class lever in Mr. Wandel's experiment. You will have multiple pocket holes in a given construction. Let's look at your table example. Most of that pressure is being distributed through the legs and into the floor, say you have four legs and four boards making up the frame that the tabletop attaches to. it's also being used in conjunction with wood glue (e.g. titebond), so you're not just looking at the strength of the screws but the glue as well.

Even disregarding the fact that you're going to glue your pocket holes, that pressure is distributed over at a minimum of two joints and much of the pressure from someone leaning on the table is going into the legs themselves, not into the class one lever directly applied to the joint like Mr. Wandel used for his experiment.

A pocket hole joint is great for face frames as rob mentioned. A friend of mine used a kreg jig to build his desk and it has not fallen to pieces around him. I probably wouldn't use it for a kitchen table as the sole joint, but I wouldn't be opposed to using them to help clamp mortise and tenon joints.

Frankly, I think Mr. Wandels' experiment is misleading in that it shows that a single joint is stronger, but the impression it gives is that you shouldn't use pocket holes because they're weak, and that simply isn't the case. I am curious to know why his experiment disagrees with Kreg's claims from "independent testing." Kreg claims that a pocket hole joint can sustain more shear load than a mortise and tenon joint. This may be true, since Wandel's test wasn't for a shear load. It might be interesting to see how that experiment was done.

Mostly I think there is opposition to pocket hole joinery because it isn't "classy." Woodworkers like to think of themselves as rustic traditionalists, carrying on a craft passed on for generations. Pocket holes may seem too much like a crutch, or being too "modern," but they're frankly plenty strong for quite a few situations, including light tables and desks.

  • As an aside regarding the traditional bit ... to my knowledge (which may be incorrect) pocket holes have been around for hundreds of years, at least since the Victorian era. Wikipedia credits their origins to Egyptians doweling at an angle but I view that as a bit of a stretch. – Daniel B. May 8 '15 at 14:10
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    Not directly related to Kreg's claims, but he did an experiment on another providers claims: woodgears.ca/joint_strength/dowel.html – Steven May 8 '15 at 14:20
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    That one seems to have held up pretty well. Anyway, what I'm saying is that his experiment doesn't really represent the forces it would normally experience, and even if it did ... a welded steel truss would support much more than a mortise and tenon, so should you only use steel trusses? As to paraphrase rob, "strongest" isn't the important thing, "strong enough" is. – Daniel B. May 8 '15 at 14:38
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    Agreed. I actually ended up getting a lot more responses than I had anticipated, so all in all, a good thing! – Steven May 8 '15 at 14:42
  • "Mostly I think there is opposition to pocket hole joinery because it isn't "classy." Woodworkers like to think of themselves as rustic traditionalists" This really isn't a valid point when talking about Matthias Wandel, his woodworking is anything but traditionalist, if pocket joinery were suffeicient for his needs I am confident he'd use it – vitriolix Jan 29 '17 at 18:47
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Pocket hole joinery is commonly used in cabinet face frames, but it can be useful in many other applications, as well. Jay Bates' website has an entire category of projects he's built using pocket hole joinery, ranging from a jewelry cabinet to a bunk bed to a bar stool.

As with many types of joints, pocket hole joinery is strong enough in many applications. For example, there are even tutorials on how to build a workbench using pocket holes.

Pocket hole joinery is really just a very fancy form of toenailing, which is a construction technique commonly used in building houses and cabinets.

You typically wouldn't subject pocket hole joints to the type of racking force demonstrated in Matthias' experiments. If you do want to use pocket holes in such an application, you can reinforce against the racking forces with additional cross members and diagonal braces.

Also keep in mind that a project using pocket screws does not have to use them exclusively as the only joinery method. You can certainly use pocket screws for some parts of a project and some other joinery method for other parts of the project.

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I have a Kreg pocket hole jig and I find it very useful. Many places where someone might only have a glued joint I will use the pocket holes to strengthen it.

The 99lbs. on a joint is actually quite a lot for many joints, because often the force gets spread out over multiple joints. Not only that by adding more screws you increase the strength. Now after all that, I agree there are plenty of joints I would not use a pocket hole for because I don't feel they are strong enough. I take that on a case by case judgement call.

I have used them often in my book shelves to reinforce glue joints. It also lets me have 'strong' joints that look 'different' if I tried to create them a different way.

One important part is the direction the screws are holding the joint together vs the direction of the normal force being put to them. Anything that would be 'pulling' the screw 'out' of the wood (such as twisting side to side) in general will eventually fail.

Every joint type has it's place, and taking things into account such as time, appearance, needed strength and expected life of the joint should go into the decision.

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Unless we are talking about some fancy glueless japanese joinery, there is a fundamental difference: both mortise + tenon and dove tails are glued together.

Pocket hole joinery is screwed together, which allows you to take it apart again. If the ability to disassemble the result of your work again at some later point in time, pocket holes are in fact superior to the other two, no matter how weak they are or what jig they require.

If that large dining table doesn't fit through the door, strong joints aren't helpful at all. and if you glue the parts together inside the room, you will never get the table back out in one piece.

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    I think typically pocket holes are glued as well, though they don't necessarily have to be. Typically if i want something i can disassemble I use threaded inserts and machine screws. – Daniel B. May 7 '15 at 20:59
  • I had assumed that they weren't glued typically, so this actually changes my view a bit.. – Steven May 7 '15 at 21:02
  • I would never have to worry about this, but if I caught a guy skipping glue on pocket holes I would fire him on the spot. – Benchwerks Mar 24 '17 at 12:53
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Everything in its place. Years ago, I morticed all my faceframes, and looked askance at guys who used biscuits. Then I switched to biscuits. When pocket holes came available on the street (they'd been in big factory furniture since who knows when) i looked down on those guys. In the last 15 years, pocket holes have become an indispensable part of our fastening repertoire.

Faceframes, yes; table aprons, maybe; chair stretchers, no; flat-edge panel glue-ups - unnecessary, wasteful, and potentially detrimental.

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I've used pocket holes. The strength can be improved by using more screws. More importantly, in your design, make sure the wood is supporting the weight, and the joint is holding things in place, and not directly taking the weight.

Nails in the wood frame of your house hold the wood in place, but they are not taking the weight directly, the wood is supporting everything.

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99 lbs applied as a first class level 15cm from the join is actually VERY strong. If you have a 4 legged table and sit a 400 lb person on top of it, each leg is carrying the vast majority of the weight to the ground, the pocket hole is not carrying that load, they are simply holding the legs in place. Leaning against the table will impart some level of force that wants to pull/push the legs apart and will test the strength of the pocket hole, but when you are leaning on something once again most of the weight is going through the two legs closest to you.

The worst case scenario would be a shelf in a cabinet where the joint itself is carrying all the weight. But once again if you have 6 pocket holes is your cabinet really going to carry more than 300lbs on a shelf? You would have to have some serious dishes for that to be the case lol.

What you wouldn't want to use a pocket hole for would be something like a chair. People throw themselves into chairs at various angles and often violently drop themselves in and let the chair catch them. No way a chair in constant use would hold up over time.

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