Do Nails Really Help?
George VondriskaDescription
Every once in a while I take some flak for not using nails or screws in my joinery, and for using pocket holes to join face frames. Let’s debunk a few myths.
Today’s glues are stronger than the wood you’re putting together, provided the joinery is good. When you have good joinery, meaning no slop or gaps between the mating parts, you’re going to get an incredibly strong joint. Let’s look specifically at cabinet construction; dadoes, rabbets and face frames.
Pocket holes have been used on face frames for a long time. Long time use doesn’t necessarily prove that something is a good method. But in this case, it is. Pocket holes, coupled with glue in the joint, make a VERY strong face frame.
The Science Experiment
We did destructive testing in this video. The test cabinet is 8” x 18” x 28”, and was built using very typical construction methods. Dado and rabbet joinery, pocket holes on the face frame, no mechanical fasteners anywhere, except for the pocket holes.
The test? See what it takes to fracture the cabinet. You may be surprised by just how much force is required. After the cabinet is in pieces we look at forensics. Where did the fractures happen? This tells us about the strength of the joint, versus the strength of the material.
If You Need More Proof…
I’ve done a gazillion edge to edge glue ups, and often get questions about adding biscuits, dowels, or other devices to these joints to add strength. Watch our edge-to-edge glue joint test and you’ll see that, again, the wood fractures before the joint.
Go Build Cabinets!
Now that we’ve increased your confidence in the strength of standard case joints, you’ll be ready to dive in and start building cabinets in your shop.
I have built a lot of face frame style cabinets. And sometimes when I do this on video, I get the question of, oh my gosh, you're not using any nails or fasteners in the dado and rabbet joinery, you're not using any nails or fasteners when you put the face frame on, you're not using biscuits when you put the face frame on, how can that be? And the answer is when the glue joint is good, the glue is stronger than the surrounding material. So I'm gonna try to do, we're doing a little myth buster thing here. I've got a cabinet that I put together. The joinery for the case is dadoes and rabbets. The dadoes and rabbets are half the thickness of the material. 3/8 of an inch, film of glue in the bottom, glue and clamp. No fasteners. The face frame itself was put together with screw pockets. I do put glue in those joints. And then the face frame is glued to the case using nothing but glue, no fasteners, no biscuits, no dominoes. S, what I'm about to do is destroy this cabinet. And what we're looking for is to see where is the failure? One, what does it take to break it? Two, where is the failure? And, I don't really know what's gonna happen, but I think we're gonna be surprised at just how strong everything is. So, let's see what it takes to make this happen. All right, let's look at the results of this crazy science experiment. Dado and rabbet joinery. This was the cabinet top. Look at what this is. That's meat from the plywood, and this was a good quality plywood. It didn't separate on the glue line, it pulled the core with it. Let's look at the face frame construction. Can you see what's going on here? This is the remainder of the stile still stuck to the rail. The glue joint didn't fail, the wood broke. Same thing on this side. The entire stile fractured, look at that. But the glue joint is still intact. Rail to case top, that didn't even come apart at all. Let's look at some more of that. This is, man, I think this is pretty impressive. The face frames are by and large, still stuck to the case. So this concept of, there's nothing but a glue joint there, you should've added nails, you should've added biscuits. No way, man, look at how that held together. Same thing down here on the dadoes. It pulled. That one's kinda still intact. It took surrounding wood with it, it didn't break on the joint. So, the moral of the story here is really that if you have a good glue joint, and you use nothing but glue to put your projects together they will stand the test of time. And two, look at, what was it, three, four strikes at the floor before the thing even fractured. So, a lot of strength there, and it really does tell us the glue is stronger than the surrounding wood. You don't need to add mechanical fasteners in cases like this. Cabinet's gonna be plenty strong.
Modern adhesives have been stronger than the wood they bind for as long as I've been alive, and I've been getting the senior discount for years. I would cringe when Norm Abrams used his brad nailer, but he always made the point that it was "just to hold everything in place while the glue dried." I supposed it's faster than clamps if time is an extreme factor and you don't mind putting holes in furniture. I've noticed nails in museum furniture, but I would imagine that was when hide glue and the like was common.
Show us one with screws and dowel in the joints before you make any claims. There are a thousand problems with your test and analysis. (BTW biscuits and dowels actually hold the alignment for the glue up.)
This video was awesome!
<strong> Ticket 20279 What about using just glue on MDF? Don't you also need to use some kind of fasteners because MDF is just sawdust and resins?
I have been a woodworker for forty plus years and have always heard glue is the strength of the joint, nails are the clamps to hold the joint till the glue dries. I have done your test myself with the same results. Glues have just gotten easier and better to use with great strength.
How do you know the good quality glue (used without nails or screws) won't deteriorate in time (eg. become brittle & crack after 40 years or so)? What evidence is there regarding longevity of these new types of glues? Many projects are intended to become "heirloom" items, but they won't last if the glue eventually deteriorates in decades from now & there's no backup support (nails or screws).
You mentioned at the end that if yiu use nothing but good glue joints, it will "stand the test of time". Given that some "heirloom" projects are intended to last a long long time