Wedged through M&Ts

[bugbear]

Bugbear wrote:

I thought the term "fox wedging" ONLY applied to stopped mortices, the implication being a hidden/sneaky method

It does. If you miscalculate with fox wedged m/t's they are almost impossible to get apart - Rob

Dry fitting to test not recommended, I gather

BugBear

 

[ByronBlack]

BTW the "foxed" tenon is a way of getting a very firmly keyed fixing in a stopped mortice. For a through mortice a foxed tenon is used decoratively, but is likely to be weakened by virtue of the bending outwards of the tenon edges and risk of breaking. Normal edge applied wedges are going to be stonger and easier to perform.

cheers
Jacob

I have to disagree. In Percy Blandfords 'Practical Carpentry' it states:

"Through tenons may have wedges driven outside them. This tigtens by compressing the tenon, which is not as efficient as spreading it."

It also goes on to explain about 'fox' wedges being applicable only to stubb or blind tenons.

OOh, get me: qouting from a book! :lol:

 

[dunbarhamlin]

This has been super informative - thanks to all - far better than a frozen reference, whatever the author, as we're getting a melding of styles and ideas from different areas of applied joinery.

Talk of foxes in the same breath as through tennons made me wonder, do blind M&Ts ever get used with a through wedge? By which I mean sort of a fox tenon, but with a square sided through mortice to allow pegs, wedge shaped on their inner part, to be driven into the joint from the other side, so only the wedge is visible on the outside. Don't expect it would have any benefits, but just might be fun as a design element.

Cheers
Steve

 

[woodbloke]

BB wrote-

It also goes on to explain about 'fox' wedges being applicable only to stubb or blind tenons.

which is what I was referring to as in Scrit's diagram. Fox wedged tenons is the term used when blind tenons are wedged and the wedges can't be seen when the joint is driven home - Rob

 

[Anonymous]

BTW the "foxed" tenon is a way of getting a very firmly keyed fixing in a stopped mortice. For a through mortice a foxed tenon is used decoratively, but is likely to be weakened by virtue of the bending outwards of the tenon edges and risk of breaking. Normal edge applied wedges are going to be stonger and easier to perform.

cheers
Jacob

I have to disagree. In Percy Blandfords 'Practical Carpentry' it states:

"Through tenons may have wedges driven outside them. This tigtens by compressing the tenon, which is not as efficient as spreading it."

It also goes on to explain about 'fox' wedges being applicable only to stubb or blind tenons.

OOh, get me: qouting from a book! :lol:

OK then whatever you call them - the wedges tapped into saw kerfs; yes, make a tight locked joint but fail due to likelihood of breaking. I know this having seen it on failed joinery ocasionally - the tenons drop out in 2 pieces.
The ordinary through wedged tenon is just about indestructible unless acted upon by external forces such as weather and poor maintenance.
An odd thing is that if not painted and subject to seasonal wetting and drying, then wedges and also dowels through tenons, once the glue is loosened, will work their way right out very slowly, by a sort of slow ratchet action. The dowels too are tapered i.e. square dowels knocked into round holes, which gives them a taper.

cheers
Jacob

 

[Scrit]

BB wrote-

It also goes on to explain about 'fox' wedges being applicable only to stubb or blind tenons.

which is what I was referring to as in Scrit's diagram. Fox wedged tenons is the term used when blind tenons are wedged and the wedges can't be seen when the joint is driven home

The diagram happened to be one I had to hand - and I was given to understand that the wedged tenon is a foxed tenon. whilst a wedged through tenon is just that, a wedged through tenon. Sorry if I (unintentionally) misled anyone, the diagram was the only one I had to hand at the time to explain the need for a straight "neck" to the mortise and the way in which wedges work.

Scrit

 

[Paul Kierstead]

This discussion is wonderfully confusing. I am expecting that some of the "wedged" tenons being spoken of here are what we might called pinned tenons or perhaps more specifically draw-bored pinned tenons.

Mr. Grimsdale, I don't think wedged one are inherently prone to breakage, it is just that they might be easy to make poorly.

 

[Anonymous]

It started off with Steve's "wedge into saw kerf" M&Ts as per Rob's very nice examples earlier. Not the same as the more usual "wedges in the side of mortice" (no saw kerf).
I just mentioned pins to confuse everybody!
BTW I don't think the hole as split inhibitor would work as the grain carries the stresses around the hole, unlike a homogenous material such as perspex.

cheers
Jacob

 

[ByronBlack]

Paul, pinned and draw-bore an entirely different beast - using dowels to mechanically fasten through the tenon rather than increase external resistance via a wedge. Good thread though!

 

[Paul Kierstead]

Paul, pinned and draw-bore an entirely different beast - using dowels to mechanically fasten through the tenon rather than increase external resistance via a wedge. Good thread though!

Well, yes.

The problem was, I did not even remotely understand:

The ordinary through wedged tenon is just about indestructible unless acted upon by external forces such as weather and poor maintenance.

as being different from the diagram. Only just now I think I figured out that he was talking about wedges driven in the direction of the long grain (of the tenon), but alongside rather then into the long grain. Without figuring out that, the discussion was extremely confusing, especially calling this sort "ordinary", whereas around there they would be very very rare and ordinary would be the sort driven into a saw kerf. Doh. This is a case where a single diagram would have greatly clarified things.

 

[Anonymous]

snip
Only just now I think I figured out that he was talking about wedges driven in the direction of the long grain (of the tenon), but alongside rather then into the long grain. Without figuring out that, the discussion was extremely confusing, especially calling this sort "ordinary", whereas around there they would be very very rare and ordinary would be the sort driven into a saw kerf. Doh. This is a case where a single diagram would have greatly clarified things.

Right, I didn't know that; it would be confusing, sorry.
Wedges in saw kerfs are very rare in my experience infact I've hardly ever seen them done like that except as decorative feature like Rob's examples. I've found them ocasionally in joinery work but usually I think they were hammered in as an afterthought when somebody had forgotten to cut the sloping sides of the mortice.
So that's the norm in Canada? In ordinary joinery too or just cabinet making?

cheers
Jacob

 

[andy king]

I was taught that in joinery the wedges are applied to the outer faces of the tenon, putting it in compression. The split tenon with the wedges in kerfs was discussed, and we were told because joinery tends to be heavier duty pieces of work, the joints need to be firmly locked, and if a kerfed wedge was applied, it was all to easy to drive them ovely deep and in doing so, split the rail.
The other consideration with external wedges is that the joints can be knocked up tight to shoulderlines which, if your initial setting out and cutting is sound, should ensure a square joint, but its still good practice to check the diagonals etc.
The principle is to glue up and push the wedges in finger tight, then tap the very outer wedges in lightly, forcing the rails up tightly to the mortice shoulderline, before driving them all fully home. Middle rails still need to be positioned to marked lines, and knocking the top and bottom rail wedges to drive the rail up tightly to the mortice shoulder only moves it by a fraction of a millimetre (unless your mortice is cut too wide!) but it's good technique.
If you have a deep bottom rail with twin tenons, the principle is still the same, tapping the outer ones in first, so if the right hand wedge is the outsde one, the other righthand one on the second tenon gets tapped as well to nudge the joint. (does this make sense?)

Hope this helps.

Andy

 

[David C]

Yes,

Joiners and cabinetmakers have different techniques.

David Charlesworth

Big thanks to Charley, a bit more signal and bit less noise would be most welcome.

 

[Jake]

Big thanks to Charley, a bit more signal and bit less noise would be most welcome.

The thing is this isn't a book, or a lecture or a tutorial, it's a discussion forum and it encompasses all sorts of characters and views, and if it doesn't, it loses something - even if individual members are relieved not have to have those views shoved in their face. One man's noise may just be another man's iconoclasm.

 

[David C]

Jake,

Good point, mine was not aimed at anyone in particular!

best wishes,
David

 

[j]

The mortise should be tapered to accommodate the extra material of the taper. Here's a drawing of a foxed tenon which should help explain it:

The tapered wedge is made to fit snugly

OK so these are not through tenons, but the principle is the same.

Scrit

Just incase anyone didn't get how that works, there's a video demo in episode 2613 on this page.

J

 

[David C]

Jake,

Iconoclasm;

Act of breaking images: opposition to image worship.

Iconoclast; one who assails old cherished errors and superstitions. (Chambers)

The latter would definitely seem to be signal not noise?

David C

 

[Jake]

The latter would definitely seem to be signal not noise?

I'll counter your Chambers with a Concise OED:
iconoclast / 'knklast/

→ n.
1. a person who attacks cherished beliefs or institutions.
2. a person who destroys images used in religious worship, especially one belonging to a movement opposing such images in the Byzantine Church during the 8th and 9th centuries.
- DERIVATIVES iconoclasm n. iconoclastic adj. iconoclastically adv.
- ORIGIN C17: via med. L. from eccles. Gk eikonoklasts, from eikn ‘likeness’ + klan ‘to break’.

So I guess that if the iconoclast isn't perceived as noise, nor is his iconoclasm.

As to definitiveness, well, in the general, and if it is true at all, then one man's iconoclasm is equally capable of being another man's noise, which is unfortunate - but I don't think it means we should shoot everyone we each perceive as an iconoclast in order to shut them up. Put some earplugs in, or ignore them or something.

 

[ByronBlack]

Getting back to subject for a second. Is there a definitive angle that should be used for the wedges? Does it have a big impact, or is it a case of just guessing a suitable angle?

And finally, does the wedge always have to be a harder timber? For instance, I wish to use Walnut wedges in beech tenons - is that a no go?

 

[woodbloke]

BB - glad to get back on topic....getting a bit lost amongst all the clever words :? Here's a pic of the spare wedges I cut for the Elm Chest a while back, you can see the sort of angle I used for them. These are in ebony and I would always use a harder, close grained, timber for the wedges if possible as they are less likely to deform as they are tapped home...no excessive force should be needed if you've got all the sums and measurements correct :wink:

Hope of some help - Rob