Pocket Screws Over Time

[Joe Angrisani]

My Dad just sent me a Kreg kit. Guess he saw the gadget guys on Woodsmith Shop or something. I have a question regarding the long-term results of using pockets screws:

How does the joint hold up over time, specifically with regards to expansion and contraction over the seasons? I've never had any type of "corner brace", removable "knock-down type" screw-mounted table legs that stayed tight over the years. After a year, or two at most, I have to tighten the leg attachment screws slightly. They appear to loosen slightly with the drying part of the year, then they stay loose.

I realize the pocket screws are in the wood in an orientation that minimizes wood movement, but there is still some movement in all planes. It would seem to me that pocket screw construction will also loosen slightly over time, just like knock-down legs. What have you folks found a few years down the road after construction?

[Lee Schierer]

I've not noted any loosening over time, you don't get much wood movement in the grip length of the screw.

[jonathan eagle]

You will use glue as well.

[Joe Angrisani]

I've not noted any loosening over time, you don't get much wood movement in the grip length of the screw.

I guess that's true. But the legs I'm refering to only have about 3/4" of hanger bolt thread between nut/washer and leg (where it is actually passing through the 45-degree support plate).

[Joe Angrisani]

You will use glue as well.

Yea, but I still don't count on end grain glue doing all that much in a butt joint. Do you?

[Brian Effinger]

My grandmother had store bought end & coffee tables that were from the 60's (or maybe earlier - I know they are definitely older than me) that were put together with pocket screws and they are still tight, even after moving with her a few times, a trip up to Buffalo to live with me for several years, and a trip back to Rochester to my brother's house, where they still reside.

[William Hamilton]

The idea of using them bothers me, just from an aesthetic or purist standpoint.. I'm probably misguided, but I plan on trying never to use them

[keith micinski]

I love pocket screws and don't see any problem with using them in hidden areas. As far as being a purist unless you are going strictly windmill power and hand tools you have already broke the rules. I quit using glue on butt joints with the screws because like you I figure the end grain glue is doing almost nothing in the way of holding power and just created more clean up. I am probasbly only 5 or 6 years into pocket screws but so far no issues.

[Lee Ludden]

I was reading an article on fastener loosening. One of the reasons they get loose is due to movement of the two mating pieces. While end grain is not a very strong joint in itself, the glue would tend to reinforce the mechanical connection, helping prevent the fastener from loosening which makes the over all joint longer lasting.

I glue all of my pocket screw joints.

[keith micinski]

I agree it probably helps a little but my hope is that it doesn't help enough to matter. I guess only time will tell.

[Don Morris]

Joe,

If it's the aesthetics of them, sure, use M & T or whatever. My LOML didn't like the idea (of those "Holes") at first too. Her father was a cabinet maker (before when pocket screws were perfected). But on cabinets or furniture where the joint is absolutely out of sight, there is nothing wrong with pocket screws. I've written before, I bought a piece of high end furniture (Stickley) recently which cost me a pretty penny. When moving it into place I noticed a couple of the out of normal sight joints were done with pocket screws. I'll bet Stickley wouldn't use them if they thought their reputation would suffer because of poor construction. After I showed them to LOML, she now feels somewhat differently.

[glenn bradley]

As Brian observes, I have very old furniture inherited from family that I found pocket-hole construction in. Everything is still tight but they only hold trim or provide a mechanical assist to a tongue and groove mating in my case. Dad has drawers out of BB ply and pocket-hole/glued butt joints. We happened to be moving things around in his shop yesterday and I had to pull the drawers out of the carcass. All still tight despite a heavy load and lots of use. I personally use PH for convenience in utility items but very, very, very rarely in furniture pieces. Its a personal choice, not a physical issue.

[Phil Thien]

Gotta use glue. End grain has gotten a bum rap when it comes to glue and joints. I've assembled face frames with glue and pocket screws, then tested to failure after removing the screws. The glue holds better than you'd think. Many times the joint breaks in the wood of the stile, meaning the glue joint is stronger than the wood itself.

Just make sure you apply some glue to the end grain, wait a minute or two, and then apply a little more glue. That guarantees the glue doesn't disappear into the end-grain (which is very absorbent).

In terms of long-term holding power, well, I've only been using them a year or so, I don't have any data yet.

[Jim Becker]

I employ pocket screws for convenience and speed of assembly. When I feel that the screw and glue alone isn't enough to stand the test of time, I'll put in glue blocks after the fact to reinforce the joint. Rarely have I felt the need to do that, however.

[jonathan eagle]

There was an issue in fine woodworking where they compared joint strength. They actually do the same testing every few years. They do MT, biscuits etc. Pockets were pretty strong as I recall. Obviously for face frames, there is little force applied to the joint in any case. You can build up a face frame in short order and you don't have to clamp afterwards. These jigs are great. By the way, I've pulled apart a glued joint and it ripped end grain didn't break, it pulled the fibers out of the other side, if you know what I am saying. This is because you normally drill your holes into the end grain piece.