Wedged Tenons: Inside or Outside

[Trevanion]

I was having a discussion with a friend who is also a fellow joiner the other day and one of the topics that cropped up was door tenons and how they should be wedged. His joinery has wedge space cut into the stiles and then the wedges were hammered into this space compressing both the stile and the tenon. My joinery has wedge space cut into the stiles but then I also cut a narrow slot on the bandsaw into my tenons for the wedges to go into to splay the tenon out like a dovetail. He argued that doing it my way could introduce cracks into the rails by the splitting action of the wedges, which is a fair enough point. I argued he was just a lazy git and didn't feel like cutting the slots :lol:

I've seen quite a lot of joinery done both ways (Worst I saw was blind mortices and tenons that were face nailed with an 18GA nailer to hold them while the glue went off, shocking from a company charging 2X as much as everyone else). I don't think there's any specific method that's better than the other, I've glanced in both Cassells Carpentry and Joinery and Modern Practical Joinery but can't really find anything specific on it. but I'd be interested in what the hive-mind thinks.

 

[Steve Maskery]

I think that both ways are fine.
Decoratively, for furniture, I prefer the saw-cut.
However, when I go the saw-cut-in-the-tenon route, I drill a little hole in the end of the saw-cut, which prevents the cut propagating into a split.

 

[MikeG.]

I think that both ways are fine.........

.........but Trevanion's way is finer. (IMO, of course). As you say, with a hole at the end of the cut.

 

[Doug71]

Saw-cut method for me, as already said I picture it as a dovetail holding the tenon in the stile.

I always feel if you just hammer the wedges down the side of the tenon you are squeezing the tenon and pushing it back out of the stile.

Regarding the 18ga nail through the tenon, in days gone by my old firm used those metal star dowels to hold doors/ sashes together so you could take the cramps off before the glue had set. Once the timber dried out a bit you had these little cross shapes sticking out through the paint work, looked awful

 

[Sgian Dubh]

I've glanced in both Cassells Carpentry and Joinery and Modern Practical Joinery but can't really find anything specific on it. but I'd be interested in what the hive-mind thinks.

Your way is, in my opinion the better way. The glue to hold the wedge in place is acting on four long grain meeting faces, meaning it's more secure. A wedge simply driven in outside the tenon is a bit quicker I suppose, but has one long grain to end grain glue joint, and one long grain to long grain glue joint, so it's slightly less secure. Most workers bore a 3 - 4 mm diameter hole at the shoulder end of the saw cut in the tenon too: this reduces the chance of the rail splitting, especially if the wedge is carefully sized, and it's not over-driven into the saw cut. Lastly, the saw cut plus wedge method is, for me, visually more attractive. Slainte.

 

[andy king]

I was taught (as an apprentice joiner, not a cabinetmaker) that the external wedging method is preferred for joinery work as it ensures the rail tenons are driven tightly against the internal walls of the mortices when knocked in in the correct sequence so that clamping is only required from stile to stile across the rails, not spanning the rails along the stile length to tighten them to the mortice shoulders, which helps keep the project external components square. (Bearing in mind that clamps shouldn't be tightened up to crushing force and within an inch of their lives, they should nip up and hold which allows any minor movement of the tenon to tighten against the mortice wall - again, taught as an apprentice)
It was explained that internal wedging doesn’t necessarily ensure this without clamping across the width and length, which made sense to me as a sixteen year old, so I stuck with it...

Andy

 

[topchippytom]

I much prefer the inside as seems to be stronger

 

[dzj]

I've repaired a lot of doors, some even from the old Austro-Hungarian period.
They all had wedged tenons like you suggest. (It is the way I also do it)
One should, of course, be careful not to fall prey to a 'we've always done it this way' mindset, but I've never had any problems with this method.

 

[Jacob]

I've made and repaired a lot of old doors and other joinery but don't think I ever encountered the saw cut method. Maybe it's just the class of work I'm used to!
I've seen it in mags of course and always assumed it was just showy detailing for added 'value' .

 

[Steve Maskery]

The reason I don't think it matters from a strength point of view is that modern glues are so good that mechanical strength is less critical than it used to be.

A saw-cut wedge creates a dovetail tenon, and thus a more mechanical joint.

A side-wedged tenon sounds inferior, but it is all face-grain-to-face-grain gluing, and as modern glues are stronger than the wood itself, I really don't thing that there will be a lot of difference, structurally.

But for furniture, I prefer the look of the saw-cut.

 

[johnfarris]

I have always found inserting wedges the most trickiest part to get right in my joinery especially on hardwood. I always wedge from the out side because thats the only way i have ever seen it done on joinery.

When i first started out making joinery my wedges would break before i had driven them half way in., I thought maybe i had the wedge ratio wrong. I then found out the correct ratio for my wedges but was still having problems. So i looked at the direction of the grain in the wedges, it wasn't that .

I thought it might be the gap i was leaving between the side of the tenon and the mortise. I have a tendency to make things to tight, stud walls being a classic example. I increased the gap and put a slop on the edge of the mortise which seems to have done the trick, but i am always a bit nervous when hammering them in.

 

[Phil Pascoe]

Cutting the tenons looks better, but I use external wedges on rough joinery. I just put a dab of PVA on the wedges - they'll never move again. The mortice can be flared but the tenon doesn't need touching - less work.

 

[Jacob]

Not just rough work - I've never seen the saw cut wedge on any old work of any quality, ever.
I might have just missed it and been unlucky but I get the feeling it's just a decorative detail giving no advantage, otherwise it most certainly would have been widely used IMHO.