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Discussion Starter · #1 ·
So I am still trying to fix up my old broken bed which had biscuits joining the footboards to the posts.

I am going to use a mortise and tenon instead, but just as I was super confident this would be a piece of cake, I came across instructions for a mortise and tenon joint with a haunch.

Now, is that something I really need to worry about?

My end board is basically a One Inch actual X 4.5 Inch Actual piece of cherry going into a 2.5" X 2.5" cherry post.

The internets said that somehow a haunch has mystical properties that could either prevent your rails from twisting, or at the very least, could help you easily convert your bed into a door if you mess up really badly... :eek:

Any suggestions are most welcomed.
 

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So I am still trying to fix up my old broken bed which had biscuits joining the footboards to the posts.

I am going to use a mortise and tenon instead, but just as I was super confident this would be a piece of cake, I came across instructions for a mortise and tenon joint with a haunch.

Now, is that something I really need to worry about?

My end board is basically a One Inch actual X 4.5 Inch Actual piece of cherry going into a 2.5" X 2.5" cherry post.

The internets said that somehow a haunch has mystical properties that could either prevent your rails from twisting, or at the very least, could help you easily convert your bed into a door if you mess up really badly... :eek:

Any suggestions are most welcomed.
The biscuits is not what is joining the bed. Most likely the bed was joined with glue.

Some people use biscuits for alignment of two boards. Some use them for increased strength. The actuality of this latter is in doubt in many minds.

Changing to mortise and tenon joints will change the size of your bed. If you want something that you feel will add strength then I suggest dowels.

Regardless, a good quality wood glue (Tightbond II) will be the primary strength in the joint.

George
 

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Discussion Starter · #6 ·
Hi guys:

Thanks for the replies.

I am replacing the whole footboard rail as well as the posts. My new footboard rail IS long enough to include tenons. So I am NOT worried about the width of the bed.

I am more than happy to use dowels, as they are easy.

But I would prefer an M&T joint since they are supposed to be stronger.

My only question is do I need a haunch or not???
 

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Hi guys:

Thanks for the replies.

I am replacing the whole footboard rail as well as the posts. My new footboard rail IS long enough to include tenons. So I am NOT worried about the width of the bed.

I am more than happy to use dowels, as they are easy.

But I would prefer an M&T joint since they are supposed to be stronger.

My only question is do I need a haunch or not???
I understand what you are asking, Stan.

There are several variations of the haunch. To be honest, I'm familiar with most but not with each of the variation's names. A simple haunch is extremely common on traditional (1730-1830) furniture.

It does help to distribute load from the rail to the stile or in this case the post with simple physics. As for preventing twisting or rotating of the rail - the rail will do as the rail choses but a notched form of haunch will add more stability.
 

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Stan to understand what a haunch does you have to know what it looks like,here`s a link
https://www.google.de/search?q=haun...HGMmctQai2YG4DQ&ved=0CDIQsAQ&biw=1272&bih=820

The haunch is not something that is added to the joint but something that is left on,the purpose of the haunch as fire medic has said is to increase the surface area of the tenon so the rail can resist cupping.

Its nothing magic it just makes the tenon bigger without cutting too much away from the stile and making it weaker.
 

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Firemedic your quite right the link I posted shows the haunches top and sometimes bottom of the tenon and this is to help the rail from cupping and that is dealing with Stans original question.
There are many names used in the terminology of mortice and tenon joints but I was taught the haunch is a part of the tenon and it is my belief that what you show in your pic is not a haunch but a "Tusk".
 

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Discussion Starter · #11 ·
For what it's worth, I am specifically referring to a haunch like this:



But I don't see how it really can add any value / strength to the joint.

The only thing I can really think of is that by reducing the overall height of the tenon (except for the haunch) you are basically reducing the amount of short grain remaining above the mortise.

And I have read in two places by "old timers" that in lieu of a haunch, using two smaller tenons (stacked vertically) or a tenon with a dowel in lieu of a haunch would work.

Again, I don't see how either way it is an advantage to just having a bigger tenon...
 

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I would think a double tenon, or a wider tenon would have the same effect. As long as it is not a bridle joint which would not reduce the amount of twisting, and might crack your post - depending on the .. eh hem.. stress the joint is made to endure.

I don't think either joint would reduce the amount of twisting if the board is green or not dry; if it is going to twist.. it will! So I think I would just use a standard M&T, and use a dry seasoned board.

However, we have a caveat.. It seems to me like you plan on cutting your mortise to the top of the post. Based on this statement, " by reducing the overall height of the tenon." which would imply that you plan on cutting the mortise to the top of the post - not enclosed on all sides -- a bridle joint. (I think). I don't think you should do that. I would enclose the tenon on all four sides.
 

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Firemedic your quite right the link I posted shows the haunches top and sometimes bottom of the tenon and this is to help the rail from cupping and that is dealing with Stans original question.
There are many names used in the terminology of mortice and tenon joints but I was taught the haunch is a part of the tenon and it is my belief that what you show in your pic is not a haunch but a "Tusk".
I've heard the term tusk before but not in reference to that joint. It's an interesting point though because in Acadian Architecture and Furniture that picture I showed is referred to as a haunch.

This begs the question of what the origins of the word are as well as the distinguishing names of the different variations.

I guess I have some research to do!
 

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I agree with the haunch not needed unless the mortice is close to the top of the post or leg. The strongest M and T for a bed would be a wedged tenon or a blind wedged tenon.

If the tenon is 1/4" smaller than the rail the last thing to worry about is a twist or lack of strength. No reason to make the tenon any smaller.

Al

Friends don't let friends use stamped metal tools sold at clothing stores.

Diagram Technology

This would be a very strong joint and it's not too hard to cut. It could be blind too.
 
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