# Why is it always that the stile is the mortise and the tenon is the rail?



## zdwiel (Feb 4, 2013)

I've looked at many doors and windows the past few weeks and every single time, the vertical stile is the mortise and the horizontal tenon is the rail in the mortise and tenon joint in the corners. Is this purely stylistic or is there a functional purpose to this arrangement?


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## HorizontalMike (Jun 3, 2010)

Good question. I have NO clue though. I suppose it has something to do with standardization of practices/procedures, in order to eliminate any confusion.


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## Loren (May 30, 2008)

I think it's traditional. It makes the door most stable in
its longest dimension. If you look at old board and batten
doors you'll see that they move in width only, and I
reckon that as frame and panel doors evolved it became
traditional to do it that way.

Also, with an entry door with a 6" stile capped by
a rail, the joint is going to move a bit like a breadboard
end.


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## renners (Apr 9, 2010)

I would imagine water run off comes into it as well


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## teejk (Jan 19, 2011)

End grain gets hidden that way. Few applications do you ever look at the top or bottom of a door. Plus stability.


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## zdwiel (Feb 4, 2013)

That all makes some sense. My first inclination was actually that you'd want it the other way around so that if there was water on your sill or threshold you would get minimal end-grain exposure, but that doesn't seem to be important since the traditional method exposes more end grain on the top and bottom edges.

I like the idea that in both doors and windows you are more likely to be looking at the stile edge than the rails and it might look nicer to not see the joint.

Interesting


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## kdc68 (Mar 2, 2012)

I believe too, it have to do with physics (gravity). The shoulder of lets say a blind mortise and tenon joint provides rigidity of downward forces that may be applied to a door or window. If the the tenon was at the end of the rail, then any downward force applied to the stile would fail the joint….Sorry for the crude drawing


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## REO (Sep 20, 2012)

had to rethink this a little. on doors of equal sized frame members there would really to no advantage but on those with larger dimensions for the tops or bottoms there would be quite an increase in strength when the tennon has a longer surface on the endgrain. it does eliminate endgrain exposure also.


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## TCCcabinetmaker (Dec 14, 2011)

1 it allows for wood movement. 
2. it increases the stength of the joint for the tenon to not run against the grain of the wood.


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## kdc68 (Mar 2, 2012)

I reread my post and I thought it didn't make much sense. I knew what I meant  So I thought I'd try again. As you can tell I'm not at all gifted in SketchUp….so sorry again for the crude drawings


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## BenI (Jun 8, 2012)

I think if the end grain had a mortise it would make it very weak and easy to split/break.

Also, if the stile had a tenon then the starting width of the board (for the stile) would have to be the width including the tenon.


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## bondogaposis (Dec 18, 2011)

It is because of gravity. Glue sometimes fails and and weight of the door would tend to cause the bottom rail to slip off of the tenon if the rail was mortised. kdc68 has it right.


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## kdc68 (Mar 2, 2012)

*bondogaposis*....thanks for that ! I really need to work on my SketchUp skills !


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## rockindavan (Mar 8, 2011)

It also makes putting on hinges easier and stronger. Otherwise hinges might fall between the long and end grain and the screws wouldn't hold as well.


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