A Frame Joinery

[Vickiana Sconyers]

Forsomething that large, I would want more than just a glue joint holding it together. I would want some sort of mechanical connection between the sides and top/bottom, such as slip tenons, dowels, or mortise and tenon.

Just a bit on the terminology, a true spline runs lengthways in a slot milled into the face of both mitres, through all or most of the joint (a through spline or stopped spline respectively). A different joint reinforcement, where a piece of wood is inserted into one or more slots milled across the corner is now commonly also described as a spline but this is more accurately described as a mitre key. In the video you link to Matthias is using mitre keys, not splines.

The strength of each reinforcement is due to three factors: structural advantage, the thickness of the wood slivers used and the glue surface area. The splined joint being superior in all regards. However, mitre keys were originally quite small and done using veneer thicknesses, resulting in only modest added strength while the keys in the video on the other hand are far larger than conventional ones and also thicker. So they probably add as much, if not more, strength than a typical spline would, being of relatively modest width (25mm / 1" being a typical maximum).

Even saying that, if you would prefer to reinforce the mitres using a method that is faster there are a few I can recommend. And the first two are guaranteed to provide greater stability and strength.

These are L-shaped steel mending plates or plywood corner braces. They are simply screwed or nailed into the frame at the back and essentially make the joint completely rigid.

Last but not least, the simplest reinforcements of all: large staples or corrugated fasteners. If you don't have any philosophical objection to using mechanical fasteners both of these require no effort to install yet add hugely to the strength of the joint, as the metal would have to shear through or be torn free from the wood for them to fail. Some people consider them crude and ugly, but they work and I would argue that their ugliness is irrelevant as they are on the back of the joint where nobody will ever see them.

LeeG's answer is a good one, but I would also say that a well done spline joint would also work, you would just have to make sure the spline goes all the way through the width of the frame not just a little corner of it.

Though on of the things you could do to make either stronger would be to make 'pins' that go through the frame from the front of a different wood, thus giving it more strength AND a nice pretty accent.

In cases where you do not want to damage the outer edge of a decorative frame (Like a nice picture frame) you could do this with a biscuit joiner. I have made many strong frames with a "detail biscuit joiner", a perfect mitered cut and wood glue.

What about adding a grove in your actual frame to allow the mirror to sit closer to the front. Then you could get some sheet material and pin/fasten from the back. Then you would have that additional cohesion of the fasteners all around the mirror.

I used pocket screws on two projects: the full-length mirror and an art piece. Kreg makes an incredible jig and has a number of great videos on how to use them. Pocket screws make tight, easy to assemble and dissemble joints. Pocket screws, though, do have some mechanical limitations. A miter frame, such as the one made below, would most likely crack open if dropped. End-grain to end-grain is a terrible joint, mechanical fastener or no.

I completed a number of pieces with brindle joints. Bridle joints look classy and allowed for the introduction of curves into my pieces. Unfortunately, this joint is fussy to set up, requires a table saw and some aftermarket accessories or it requires a few hand tools and lots of patience to complete. I had a number of chances to practice and I was never satisfied with the results.

We are working on something like that but it will not be printed. Take a look at the post at -and-beam-knee-brace-connection/ and scroll down to the middle of the page to see a download link of an example of what we are working on.

Can you discuss the relative strengths and merits of different woods and trees? Is southern longleaf or yellow pine suitably strong as a beam? And does it pose any particular problems, twisting, excessive shrinkage drying after being cut green?

SYP is suitable for timber framing. Both of my personal frames have them. They are stronger than most other species in the SE. They do twist, bow and move more than other species but that can be accounted for in some cases.

I've been using the Kreg for trim work for a long time now, but not face frames. I'm leaning that way because I know how fast and easy it would be, but am somewhat concerned that the joint could twist if it got hit by a heavy pot on the way into the cabinet or some similar impact.Steve

"Yes, mine too, but I can still twist a joint with two screws in it if I try hard enough. Can't do that with a doweled and glued joint. "what?

Put some glue in your joint. Are you implying that two wood dowels are stronger than two steel dowels, aka screws? Seriously?That doesn't make any sense.

Yes, they can twist. I've done it simply by taking the two joined pieces in my hand and twisting. I've even been able to do it to a glued kreg joint. It's end-grain after all, doesn't take much to crack it. The pre-drilled pilot holes on the side with the screw heads have a little slop in them. A doweled and glued joint solidifies when the glue dries.I'm pretty convinced it's a non-issue, but still thinking some manor of glued tenon or dowel is stronger, just not sure it's worth the extra effort. Now if I had one of those Domino joiners...Steve

You must have had a sloppy jig , or a bent drill chuck, pan head screws or something, or you are subconciously creating a reason to stay in your comfort zone, because if done correctly a double screwed, glued joint will not twist before breaking, it's physics or something!

Table saw set to 45 degrees, stile on edge against the mitre fence, raise blade till cut just reaches the depth of the bead. Test cuts to get close, sneak up on it till you are there. Rip away the waste bead with the table saw, clean it up with a chisel. The rail pieces are easy, just nip 'em on the chop saw, again sneak up on it, till it fits. Gets a little trickier with mid-rails.Steve

Those strength studies/stories pop up in the magazines pretty regularly. If I recall, loose tenons usually win, even over mortise and tenon.In this application it's not really a question of breaking strength. There is really no worry about a kitchen cabinet face frame joint breaking. I sometimes use a sub who makes cabinets without joining the face-frame pieces at all, rather he mounts them to the carcass in individual pieces. I've not been happy with that, and run screws in from the sides after the fact to hold it all together (paint-grade work, obviously).To me it's more a question of the stability of the joint resisting movement due to humidity changes and the occasional whacking of the frame by pots and pans being put away. A cast-iron LeCruset stock put has a good deal of mass, and I've seen my wife bang 'em into our cabinets pretty good.Most of my cabinet work is paint grade, and any joint movement telegraphs through the paint eventually.I'm sure Kreg construction is fine. And that's probably what I 'll wind up doing this time. As I said, I've been using it for trim joints for years. That said, the commercial houses use it because it is fast and cost-effective, not necessarily because it is the best joint. If I was doing a lot of custom cabinet work, I think I would buy a Festool Domino Joiner, but at 700+ dollars, I can't justify it for a few cabinets a year. Anyone out there using anything besides Kreg or Biscuits? Anyone tried the beadlock system? Or the the miller tapered peg system?Steve

I have a Kreg jig. I've used it hundreds of times. For me, it's the best way to put together a face frame. You don't need the strength of a M&T joint here -- the strength in the frame comes from the cab to which it is fastened. All you need is to hold the frame together until you shoot/glue it to the cab front.

If you go with a Kreg, be sure to get a set of the joint clamps as well -- the ones that look like vice grips with round disks on the business end. These will keep the joint perfectly aligned during assembly. I glue my joints, but I don't suppose that's really necessary since, as stated above, the cab holds everything together.

Mike,I suspected the beadlock jig is more trouble than it's worth. My partner and I have three different Kregs between us and face clamps to go with them. I have the old metal one, and the face clamp that came with that one is not as nice as the one that comes with the newer plastic ones.Steve

A C-style Visegrip with swivel jaws and a washer tack welded on had to be cheaper tho'. I have kreg kit in the van and the super duper kit in the shop..and found those clamps I made up to be useful for a lot of other stuff too, like hanging a riggers bag on a scaffold bar. Or raising and lowering stuff with rope.Spheramid Enterprises Architectural Woodworks

Contrary to what a lot of people thought, the Wood mag joint tests found the half-lap to be, by far, the strongest joint. Now, whether or not that's pertinent to your current question is up to you...just FYI.

I did some frame like what you want to do about a month ago and used the kreg jig, it works very well. The domino is nice but you still need to clamp the frame, the kreg screws are your clamp. Like other said, if you use glue, you cannot twist a FF with pocket screws. I actually made a mistake on on FF and tried to take it apart. I used titebond II and had only screwed it together about 30 minutes before I realized my error but that was too late. I tried to take it apart but there was no way I could get it apart without breaking the wood (poplar). After that, I would never use anything other than titebond, that strength was amazing, and after only 30 minutes. After any join with pocket screws and titebond sets, there is no way in the world pots, pans, kids or anything else could move that joint. Really it is probably impossible for the joint to break, the wood surrounding it would before the joint.What you talking about as far as just using pocket screws, no glue, twisting is probably dependent on the type of wood. Some of the softer wood would allow you to twist if you applied enough pressure. That's not the joint as much as its the softer wood not holding the screws as much. But I thinks it crazy to use pocket screws without glue. I think 99% of the time the screws would be perfect but how much effort is a little glue? Just like construction adhesive on a subfloor, nails alone wood be good but glue is the extra.

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