Is Glue Necessary with Pocket-Hole Joinery?
From contributor B:
Glue is not needed for face frames when pocket holes are used with 2 screws at each joint. However consider this if you glue the face frames on the box and use pocketholes to put the face frame on, since you are glueing it all together at once with no overspill of glue on the front of the face frame from the joints.
From contributor T:
I have also read that glue is not necessary with pocket hole construction. However, I still glue every joint. It is probably a little stronger, and is surely a little more time consuming but it gives me just a little more peace of mind. It is worth the time to me.
From contributor F:
By not gluing the butt joints it will make for uneven joints later. These joints should be glued. The glue will keep the joints nice and tight and will not allow them to move in time.
From contributor L:
I use glue on my pocket screw joints. It solidifies the joint and makes it seamless when finishing with stain/lacquer or primer/paint.
From contributor J:
Absolutely Contributor L. Glue has some nice gap filling properties and those screws will work loose even in the slightest eventually leaving small gap. Yes, itís a little messier but worth the time to me. I have a Ritter face frame clamping table and according to the manual they even say glue is not necessary. Maybe I'm just a little picky, but I like the solidity and gap filling properties of the glue.
From contributor R:
Do yourself a favor and make up a couple of samples, one glued and one not. I like to show my customers how strong the glued pocket screwed joint is when the screws are removed.
From contributor P:
I use glue. It's good insurance, especially for those joints where the screw is not quite as tight as it should be. Second question - does everyone who uses pocket screws to attach face frames to boxes use glue?
From contributor K:
Yes. I look at the screws as insta-clamps to speed assembly and back-up for the glue; not the other way around.
A couple of years ago, I attended a workshop concerning cabinet making and the pro's and con's of pocket-hole joints. The instructor stated that screws were enough for kitchen cabinets since the average life of a kitchen cabinet is less than 10 years. The joints do not undergo extreme tension and therefore glue was overkill. He went on to say that if the joint was going to undergo abuse routinely, and you wanted it to last a long time, then glue should be used.
I see some good points other woodworkers have made about bridging one piece to another, but for strength, pocket holes are strong enough for the cabinets I construct. It also allows me to replace a section in case a piece cracks or becomes discolored. In dealing with hickory, this happens to me frequently. With glue, it is much harder to go back and repair or replace. Again, I guess I am lazy because I would not go back and replace the complete face frame.
From contributor P:
Anyone who says cabinets are only supposed to last less than ten years is probably trying to convince a new generation that pocket screwed joints whether glued or dry are sound construction. There is no long term strength in a glued end grain to face grain joint. Seasonal wood movement will loosen screws. I donít want to hear it - I have tried to repair loose pocket screwed face frame parts for friends with 1 year old kitchens.
Cabinet makers would actually consider not gluing the face frame to the box? I donít ask prospective clients if the are willing to pay for high quality work. I do well my face frames together and dovetail my drawer boxes and grain match my doors and drawer fronts. If they donít like my price they look elsewhere.
I am not going to butt join and brad together melamine drawer boxes for anybody - Iíd rather close my shop than go there! I think it is some kind of sin to take good materials and make something shoddy out of them that will self destruct in less than a decade when it could be built to outlive the purchaser. How would you like to buy a house with a life expectancy of less than ten years?
From contributor P:
To be fair about it Contributor M, I have never built frames with the screws and then been able to check on jobs that were done long ago to see how the joints were doing. I base my skepticism of how long they will last on old wooden things with loose wood screws which I have seen throughout my life and attributed to seasonal wood movement slowly working against the metal screw threads.
I am telling the truth about friends with a one year old kitchen asking me to come and try to fix a loose interior stile (mullion) that was joined by pocket screws. Of course that in itself doesn't mean much but I do know a dowelled one wouldn't pivot even if you forgot the glue.
Also, if it is true that things have changed and cabinet makers need only build their product to last 8 or nine years, maybe the pocket screws keep joints tight that long, I really donít know.
While its true that people will always be looking for faster ways to do things sometimes faster isn't the same quality as the slower way. I know I would never be able to sell you guys on dowelling but Ill bet there are way more shops doing it then you may think. We have pneumatic operated boring equipment to speed it up but I am sure pocket screws are quicker (especially if you donít use any glue).
By the same token, I wonít be talked into mortise and tenoning my face frames together by some old fossil because it takes too long and my cabinets only need to last 75 years instead of 150 years.
History has a way of repeating itself so donít be surprised when you find yourself in my position wondering why the latest generation of cabinet makers is using the latest method of joining face frames that isn't near as good as the quality of pocket screws.
From contributor K:
Like many, I've fabricated cabinets various ways over the years, and I believe your assertion that pocket holing "with or without glue" is not sound contraction is a weak position.
Done correctly, pocket holing is a very sound construction technique. In our case, not only is the face frame pocket holed at the joint with glue, but the frame is then also pocket-holed and glued onto the cabinet box all the way around. By doing it this way, even with normal wood movement, the joint maintains it's integrity, as it is supported by the glue and screws at the joints, and the glue and screws going around the cabinet box. Add to the fact that the cabinets are also screwed together on the wall near the face frame, the cabinet screwed to the wall, and the horizontal and vertical movement is not even measurable in this scenario.
Even if the glue were to totally fail (a very unlikely scenario), the face-frame could not come loose from the box, unless the screws snapped off, or the wood totally failed, as they are basically clamping the face-frame on the cabinet box with inward surrounding pressure. The same cannot be said be said for doweling, which the dowel acts as the pin, is usually wood, and subject to moisture and movement factors. The pocket-hole screw itself, being metal, is not subject to these factors to any measurable degree. So, even if the glue failed completely, if the face frame is attached as stated above, it has nowhere to go.
Having started in construction when I was in my teens, I can tell you before metal connectors and hangers, that most house were constructed with pocket-hole construction, it just wasn't called that - it was called toe-nailing. Pocket holing came from using a larger bit to start it and a smaller bit (later on as this developed) to complete where the head of the nail or screw met the beef of the wood where the wood met at the joint.
Most studs are "toe-nailed" into the top and bottom plates of your walls; you won't typically find many, if any, connectors in most interior walls, and this is done without glue. So to say that pocket-holing "with or without glue" is not sound construction, again, I believe is a weak point. Pocket-holing, in practice, is no different than toe-nailing, except it is supported by glue, screws, cabinet and walls. Then again, I use all 3/4" material, so that could be a factor. We switched to pocket-holing 6-7 years ago, and we warranty our cabinets for 20 years, and we've (knock on wood) never had a cabinet-related service call.
Now, all that said would I assemble a cabinet without glue - no. I wouldn't just dowel or mortise and tenon or half-lap or staple or nail or dovetail the ends without glue either, but, then again, I've only known pocket-holing with glue as an assumptive factor, so who knows. It wouldn't be the first or last time I learn something new, but I can't answer the question of whether or not pocket-holing would work with no glues, but with a 20-year warranty, I wouldn't want to find out the hard way.
Something tells me though, if I pocket holed a frame together without glue and did one with glue, I'd have a much hard time disassembling the one with glue.
From contributor P:
To contributor K: I realize that a pocket screwed face frame that has been glued to the front edge of a carcass is not going to fall off. Overall, my feelings are that there will be cosmetic problems (not major structural) sooner with these screwed joints than with more time consuming methods such as dowelling. In other words, I believe there will be open joints between styles and rails etc sooner than with other methods of joinery. Dowelsí eventually succumb to cross grain movement and the joints will show gaps too.
My friends pocket screwed face frame repair job was the case of an interior style(mullion) that had no carcass member (partition) behind it to be glued to. The weight of the 12" wide door that was hinged to it caused or helped the pocket screws to fail. This was only a flat panel cherry door, not the heavier raised panel or slab type door. This mullion came loose and was pivoting in less than one year after being built. So, that leaves no doubt in my mind that a dowelled joint or better would be stronger than screws.
No doubt either that the skill of the guy doing the pocket screwing plays a roll in how good any one joint is. Unlike dowels, screws can be over-tightened and strip out the pilot hole in the wood, be left loose and etc. It is evident from what Kap says that someone who cares can assemble these joints better. Just remember that disgusted customers do not always call a business to tell them about superficial problem with their products.
As far as screwing the face frame to the carcass thatís fine. After the glue sets you could take those screws back out because that kind of glue joint will last a very long time. Someone above said I should test end grain glue joints. Hey, I know they stick! I also know that wood moves across the grain year after year and those joints will fail way before a long grain to carcass glue joint will fail.
From contributor W:
I typically inset my doors. This means I'm counting on quite a bit of help from the face frame to keep things straight and square so I glue up my face-frames with mortise and floating tenon, and then I biscuit-join the face-frame to the cabinet, which is not necessarily a 'box' but may be a long run. I like pocket screws for some applications but assembling face frames isn't one of them.
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