David Marks and Loose Tenons

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This was demonstrated on diynet..
http://www.diynetwork.com/diy/hi_tools/article/0,2037,DIY_13936_3119901,00.html
The process is no more complicated than creating a dowel joint, (and in fact, the drill jig could be used to create dowel holes if desired.) The secret is that once the jig is clamped to the workpiece, and you drill a set of holes, there is a slide mechanism, that allows the jig to move exactly half the distance between the holes. Sounds complicated, but after watching a demonstration, it is a very simple process.
(shims are provided in the kit, if offset tenons are to be used.)
http://www.beadlock.com/ sells the jig and the necessary router bits to create just about any size, or length of loose tenons, that you would desire or you can buy the tenon stock premade. (The router bits to make the tenon stock cost more that then jig...)
I have NOT bought one of these, yet, and I would certainly appreciate any downside to the system, that I'm not seeing.......
James...
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Works as advertised. You sometimes have to heat up the tenon stock to shrink it to fit because it absorbs a little moisture. And put the drill in the hole a few times to make a nice clean hole...
ken
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Let me add to the confusion.
Would a biscuit and glue provide the same level of stregnth? I'm adding a bottom shelf to a coffee table and am trying to decide on the joinery for the shelf support. The shelf is 28" square made of makore. I'd like to use biscuit cause it's quick and I already have the tool.
Any thoughts?
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Biscuits construction isn't as stout as M&T; just quicker. I use both, depending on what I want to achieve.
Dave
mrcomp_ca wrote:

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a
dont be confused ,loose tenons are what you make when you cannot make the right ones.Tenon are intended to be as tight as you can get them .in the good old days you would have been out the door if you made loose tenons ...mjh
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What a load.

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You aren't serious, are you Mike?
"As tight as you can get them" isn't the correct way to size a M&T joint, but I'm betting you already know that...
Dave
mike hide wrote:

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cut
of?
him.
the
I meant exactly what I said.
In the past ,and I have furniture to prove it Mand T joints had no glue ,they were secured by pegs anything but a perfect fit would ensure the structure would "rock" and secondly would soon fail...mjh
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We're talking Fuji apples vs McIntosh apples. <g>
M&T, when glued, need to be less than "as tight as you can get them".
NOW I find out you were talking pegged...
Dav
mike hide wrote:

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Nope, you just need to think of how the M&T joint works. In load direction, the tenon takes the force. At right angles to load, the shoulders resist movement when they register against the other piece - thus the pegs or draw boring, which substitutes for a clamp in assembly. The glue may be omitted or may crumble, leaving the joint mechanically sound.
If you want to know what happens to unshouldered tenons, look at the loose rungs on any chair.
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direction,
draw
omitted
Tenons are subject to two loading conditions and hopefully not three . The third a longitudinal load ,would call for a dovetail joint as opposed to a modern mortice and tenon.[non pegged]. A pegged tenon would even take some longitudinal load .
An unpegged tenon basically is subject to bending and shear loads . The shear load is applied at 90 degrees to the tenons length, thus the load will crush the glue film [which has thickness with a sloppy tenon /mortice.fit] between the bottom of the tenon and the bottom mortice surface until the shear load is resisted . this will result in a compression in the lower glue thickness and a tension in the upper one with commensurate strains [movement].
The second loading is due to the moment the load causes . This load results in a point loading of the lower outer edge of the mortice and the upper inner edge of the mortice . The former results in even more deformation of the glue layer [in addition to that resulting from the shear load ] and a reverse deformation at the upper inside of the tenon/mortice .
This loading condition occurs whether the tenon is pegged or not. The pegged haunched tenon does somewhat better as the effctively the peg keeps the tenon "engaged" and tight allowing the haunch to spread the bending loads..
The bottom line is in the case of a tight fitting mortice and tenon the glue joint thicknesses are mininized resulting in the basic wood taking the loads directly rather than allowing the loads to be transferred through the glue thicknesses for which it is ill suited to do . Wood to wood contact results in less flexure and longer joint life .
having a sloppy joint is akin the having a poor edge to edge joint and hoping in the poorly fitting sactions that the glue will take the load ,we all know how that works ....mjh
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I never said to make a "sloppy joint". But "as tight as you can make them"? I take that to mean you'd make a glued M&T so tight you have to "persuade" it together. If by "as tight.." you meant, PROPERLY snug, then we are in agreement.
Dave
mike hide wrote:

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A tight joint in my book is as perfect a fit as one can get, that is not a force fit..
A loose tenon in my book is a sloppy or ill fitting joint and that is what this thread is about isn't it? obviously CW and David disagree....mjh
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Excuse the interruption, but a "loose" tenon only means that the tenon is a separate piece of wood.
It's a square dowel that can be as wide or long as necessary.
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wrote:

No, actually, it isn't. It was a discussion of the loose tenon method of joinery employed by David Marks. Loose tenon, as in two mortises and a separate tenon glued into each. I suspect that you're not so completely dense as to have missed that and are just being your usual obtuse self.

And rightly so. You're the one who's screwed up
--
LRod

Master Woodbutcher and seasoned termite
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a
what
Being my usual Obtuse self, I read the original post by Stoutman, perhaps you should also . There is no mention of the method of constuction, just that they are loose tenons
.Even though I have never seen David Mark's program let alone ever heard of him . So what would a brilliant person like yourself by name a loose tenon might be ? surely not a lousy fitting tenon.....mjh
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wrote:

The one whose subject is "David Marks and Loose Tenons" as can clearly be seen in the subject line of this post as well as the others to which you've responded? I read it.

Then what earthly reason is there for you to insert yourself in a thread in which fully half of the subject concerns David Marks and the other half a process with which you are clearly unknowledgable?
You're as bad as toller giving electrical advice.
--
LRod

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of
Again read the first post in this thread by Stoutman ,not the one you choose to suit your purposes.
I was not concerned with the author but with the subject, loose tenons. I assure you I do know what a tenon is and exactly what a loose tenon is by general woodworking standards.
Your assumption that I am unknowledgable about " Loose Tenons" as defined by Marks has absolutely no basis ,you have no idea what I do or not know.
As a matter of fact you would appear to be a nasty little know-it-all yourself., Being that it is surprizing you bother with mister Marks or the subject matter as it all has to be old hat to you.....mjh
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wrote:

Is this the post to which you refer?:
: : This has probably been asked before, but...
: I recently started watching David Marks on DIY. I have yet to see him cut a "real" tenon. Always loose tenons using a multi router.
: Why is this? Is there an advantage to loose tenons that I am unaware of? Does he just like to show off his multi router? Are they just easier to make?
: I use to only watch Nahmmy and I have learned 90% of what I know from him. Nahmmy "rarely" made loose tenons.
: Confused... I read it...again.

Well, there it is. The subject says loose tenons, the first paragraph says loose tenons. The second paragraph says loose tenons. The third paragraph says loose tenons. It seems pretty clear that the subject was loose tenons. Not the fit of conventional, integral mortise and tenons, but loose tenons as a joinery technique. By general woodworking standards.
A huge clue that it was indeed a loose (or floating, as someone else called it) tenon thread was the mention (twice) of the multi router.

Your words say otherwise. For example, you said you don't even know who Marks is ("[e]ven though I have never seen David Mark's program let alone ever heard of him"). Therefore, one can only conclude that you are unknowledgable about loose tenons as defined by Marks, by definition.
And that's what the subject was and you were off the subject. Even David and CW thought so.

Ah, ad hominem attack. That'll prove your case
--
LRod

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Loose tenons and floating tenons are often used as synonymns, hence some of the confusion.
For example: http://www.taunton.com/finewoodworking/pages/w00118.asp
I disagree with none of what you, Mike, have written in this thread.
Patriarch
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