Double M&T Joints

[JFC]

I think we should rename the relished tenon a Scrit tenon as he found out the meaning and no one else knew :lol:

 

[Scrit]

So "relishing" is taking out the middle bit then? I call it a "relieved" tenon, don't know why, I might have made it up myself: any tenon which is less than the full width of the piece.

What I'm wondering is whether or not that terminology may be local to the district where I now live. The only references to "relishing" that have ever discovered were in machinery catalogues by Ransomes-Pickles of Hebden Bridge. Modern manuals tend to refer to the "relish" as a "central haunch" and the old chap who confirmed the term "relish" for me in a discussion earlier this week served his time in a joinery shop in the same town more than 60 years ago (he's well into his 80s now) and can remember using one of the machines in question. So perhaps it was a term dreamed up by the manufacturer?

Scrit

 

[Steve Maskery]

Why cant you say more here Steve ? I earn my living from working with wood but always give my tips etc publicly

Because I have a commercial business which operates in this area and it is regarded as advertising if tell BB where he can buy such information. But as far as I can tell, it's OK for me to say that there is such info out there, but he has to find it for himself. Of course, I can be much more explicit by email, off forum, but the initiative must come to me, not from me.

I hope that's clear and uncontroversial.

Cheers
Steve

 

[ByronBlack]

Guy's, as usual, i'm super grateful for all the excellent information - and the interesting debate.

Scrit - cheers for the book recomendations, alongside Joyce's one i'll add these to the list. I think i'll read up more about the joints before I think any further on teh subject.

I'm in two minds at the moment about which joint would be best. Because of the width of the stretchers, i'll definitely have to use a twin-tenon as in the picture, but I don't know whether to go for through tenons with wedges, or a proper knock-down wedged tenon version.

I don't intend to move the bench, and i'm viewing it as an heirloom piece, so I want to do it as traditional as possible given the circumstances/skill level. I've already discounted using bolts, for the totally irrational thinking that I want the bench to be constructed only from wood and related joinery techniques.

Cheers again for all the tips etc.. i'll check out the book recommendations and see where the rest of this thread goes.

Jacob, this is a real newbie question. But just how do I got about making a rod for such a joint?

 

[Anonymous]

Why cant you say more here Steve ? I earn my living from working with wood but always give my tips etc publicly

Because I have a commercial business which operates in this area and it is regarded as advertising if tell BB where he can buy such information. But as far as I can tell, it's OK for me to say that there is such info out there, but he has to find it for himself. Of course, I can be much more explicit by email, off forum, but the initiative must come to me, not from me.

I hope that's clear and uncontroversial.

Cheers
Steve

Steve
I don't think you should worry too much about advertising as you have made a clear statement of your sponsors and your posts all (AFAIR) give info freely in an unbiased way etc etc and anyway we are all grown up (more or less).
OK we got a bit bothered about Nick Glib but that's cos he seemed to think he was doing us a big favour by appearing here at all :roll:
So keep up the good work.
I should declare an interest here; my involvement in this group is all part of my plan for total world domination.

cheers
Jacob
PS I still haven't fixed up that wheel so I might have to offer it on at some point. I discovered freehand sharpening in the interim, and am trying to work out how to make some dosh out of it - difficult, cos there's nothing to sell. :roll:

 

[Steve Maskery]

I don't intend to move the bench, and i'm viewing it as an heirloom piece,

You might not expect to move it, but someone else may have to, one day!
S

 

[JFC]

Ahhhhh thanks Steve







I'd have told him anyway :lol: rules are made to be broken remember :twisted:

 

[Anonymous]

snip
Jacob, this is a real newbie question. But just how do I got about making a rod for such a joint?

You don't make a rod for a joint - you do it for the whole item. It's effectively a full size drawing, usually of vertical and horizontal section, showing every detail. You lay the planed up pieces on, and take measurements off with a set square or something similar. It's in the books, and there's a lot on this group if you search.

cheers
Jacob

 

[Scrit]

You don't make a rod for a joint - you do it for the whole item. It's effectively a full size drawing, usually of vertical and horizontal section, showing every detail.

This does, of course, pre-suppose the existence of either a scale drawing or at least a dimensioned sketch. Doesn't it?

Scrit

 

[Anonymous]

You don't make a rod for a joint - you do it for the whole item. It's effectively a full size drawing, usually of vertical and horizontal section, showing every detail.

This does, of course, pre-suppose the existence of either a scale drawing or at least a dimensioned sketch. Doesn't it?

Scrit

If it doesn't exist already then you create one. You've got to decide on what you are making, and all it's dimensions, at some point, so you do it at the beginning and put it on the rod.
On the other hand I suppose you could make stuff in a freehand sort of way like a sculptor, adding a bit, taking a bit away, but it would be a long drawn out procedure. I've seen people do building conversions that way and I find myself having to explain that rubbing out and re-drawing a pencil line is much easier than pulling down and re-building a wall.

cheers
Jacob

 

[Scrit]

I've seen people do building conversions that way and I find myself having to explain that rubbing out and re-drawing a pencil line is much easier than pulling down and re-building a wall.

Oh good, so it's not just me that gets 'em :roll: :wink:

Scrit

 

[ByronBlack]

The design most definitly exists only in my mind, however, I did go to the effort of working out dimensions before I started.

But something as big as the workbench would make quite an unweildly rod? Also, when you say rod, do you mean a section of thin by long wood with the dimensions marked on it, OR a proper sized drawing on paper? If the latter, how would that help with the marking out and consistency of the joint? I can quickly make a sketch and work out hte proportions, but I don't see how that actually helps in the practical aspect of cutting the joint..

 

[DaveL]

Byron,

What you need is a batten (the rod) and you mark all of the positions on it for the details of the leg. Then when you make the set of legs you mark each one from the rod, so they all end up the same.
You never need to measure the dimensions separately so you should not end up miss measuring one of the set. :x
In a pro shop they would made the rod from a full size drawing, you don't have to draw one this time but we may be popping over to inspect the drawings for your next project. :wink:

 

[ByronBlack]

Thanks for that dave - thats what I had in my mind but I got a little confused from Jacobs mentioning of the full-scale drawings, like I would do anything as professional as that!!

Your most welcome to come over and inspect my work, you may be able to help me lift the heavy bench into place

 

[Scrit]

Then when you make the set of legs you mark each one from the rod, so they all end up the same.

You actually try to clamp the legs as a set or at least in pairs for marking - much more accurate

In a pro shop they would made the rod from a full size drawing....

Do they? I've always used scale drawings and scaled up for making the rod........

Scrit

 

[Anonymous]

Thanks for that dave - thats what I had in my mind but I got a little confused from Jacobs mentioning of the full-scale drawings, like I would do anything as professional as that!!

Your most welcome to come over and inspect my work, you may be able to help me lift the heavy bench into place

OK its drawing but its not Leonardo de Vinci so don't be put off - nobody's going to see it except you. Just see it as a record of the measurements you've taken or worked out.
I'd advise keeping your bench design simple - ignore those rather affected designs with slightly splayed legs etc - difficult to do and pointless.
Assuming a simple design, what you do is:
get a piece of board, ideally a 6" wide length of MFC from B&Q, longer than your bench.
Pencil in 2 lines with your square, at the length of your top boards. TA-DA thats the 1st bit of rod - you now can lay on the boards you've prepared and take off the lengths with a set square and a pencil, knowing that they will all be exactly the same, but you don't do it yet - you start the cutting list when you have completely finished the rod.
Then pencil in 2 lines for the width of each of the legs in position relative to the top marks you made earlier. TA-DA you now have the 2nd part of the rod - marks which show the length of each rail and apron and the position of the shoulders. You now pencil in lines for the haunches and TA-DA you now have ALL the horizontal marks you need for the rails and aprons.
Then do the same for the width of the bench etc. You could overlay the width drawing on top of the length drawing if the legs are square, to save a bit of drawing , or you could do it separately to save confusion.
You then do something similar for the vertical bits: on the opposite edge of the board put in marks for the ground to bench top height, then the thickness of the top boards (TA-DA that gives you the length of the legs), then the position of the rails and aprons etc ( gives you position of the mortices), then details of mortice haunches or however you are doing it. And so on.
You could mark in the the depth of things on the board with a combi square and a pencil, at which point it starts looking like a full sized drawing. You could add details about vices and so on, as much or as little as you need.
To take off the marks you lay on the planed square pieces (marked with face and edge) stacked up - face mark to face mark where they are same but opposite, and mark with a set square and pencil.
Does that make sense?
Re drawing - it's inescapable for a woodworker you can't manage without it. Just a simple drawing board, T square, set square, pencil and rubber, scale or two. Don't bother with Sketch-up or other drawing program they are a waste of time and useless for our purposes.

cheers
Jacob

 

[JFC]

I must say it is nice when you have a good drawing to work to . Some of the architects drawings i have been given for loft conversions have been laughable with no detail whatsoever just a pretty picture of a house with a few trees drawn in for some odd reason :? Some of the specs have also been 10 years out of date but thats another story .

 

[spadge]

Size for size, loose tenons are just as strong, and much easier to cut, as traditional tenons.

Agree they are easier to cut but Fine Woodworking fairly regularly do tests on joint strenght and the loose tenon is always weaker than the same size M&T. The difference isn't great and both joints are very strong so I think in the vast majority of cases you could happily use either joint, but if you wanted ultimate strenght you should use a traditional M&T joint.

FW only test the joints to destruction i.e. a corner joint is placed between a press and the force required to break the joint is measured. They have (as far as I know) not done a durability test i.e. "waggled" a joint for a while until it fails. Does anyone know if this sort of test has been done?

I ask because there seem to be lots of chairs made with loose tenons at the seat joints and I wondered whether they would be as durable as the traditional M&T joint?


Cheers

Grahame

 

[Steve Maskery]

Spadge, have you got a reference for that, please, I'd like to look it up?
Thanks
Steve

 

[Anonymous]

Size for size, loose tenons are just as strong, and much easier to cut, as traditional tenons.

Agree they are easier to cut

Yebbut you then have 2 mortices to cut surely? That's not easier it's extra work surely?

but Fine Woodworking fairly regularly do tests on joint strenght and the loose tenon is always weaker than the same size M&T.

Bound to be weaker as it is effectively 2 M&Ts to fail instead of one, and difficult to wedge

The difference isn't great and both joints are very strong
snip

You don't find loose tenons (hardly ever at any rate) in trad work except in board jointing where it can't be a fixed tenon, often pinned and drawbored. Loose tenon is weaker and more work, why bother?

cheers
Jacob