# Tenon width / sizing



## MarkShultz (Nov 9, 2011)

Sorry for the long multi part question. Need advice for a series of loose tenons for a new exterior door I'm building. All rails and stiles are 2" thick hardwood. Stiles are 5.5"

1 - what is the minimum distance from the end/edge to leave as solid wood? The below questions assume 0.5"

2 - bottom rail - assuming I have an 8.5" rail, then I have 7.5" of space for the joinery (0.5 solid space at top & bottom). What width of tenons? Using 3 tenons, and 0.5" btw each tenon, then I would have 6.5" for tenon's, and each would be 2 1/8" each. I'd prefer to use only 2 tenons, but that would imply 3.5" each, and that violates the 5x thickness rule I've read about (5×0.5 = 2.5" max). Or should I do 2

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2.5" and 1
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 1.5"?

3 - middle / top rail. assuming I have 4.25" of space for the joinery (0.5 solid space at top & bottom). What width of tenons? Using 2 tenons, and 0.5" btw each tenon, then each would be 1 7/8" each. Does that seem right?

4 - for the middle rail where the lock will be placed, how deep should the mortise go? Im thinking shorter is better here, so say 2"?

Many thanks!


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## MadMark (Jun 3, 2014)

Traditional rule of thumb is tenon is 1/3 of stock thickness inset the same distance on the edges. For thin stock use 1/4-1/2-1/4 ratio. (1/8-1/4-1/8 for 1/2 stock etc.)

Tenons are strong vertically, pretty strong laterally but weaker against pullout. Add pins if pullout is expected to be a major issue. Knock down tenons can be wedged.

Two mortised pockets are less likely to split the leg than one big one.


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## RichT (Oct 14, 2016)

I've never heard of these rules you're talking about. I don't make a single tenon more than 5" wide to avoid problems from wood movement. If you go with two tenons, only glue the top ones and let the bottom ones float. However, for an 8 1/2" rail, a single 5" tenon is plenty strong, and will give you more gluing surface. Regarding depth, 2" is plenty, and there's no need to pin them. With a good glue job, the main thing pins offer is visual.


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## wapakfred (Jul 29, 2011)

I've generally stuck with what Mark said about the thickness of the tenon. That usually works fairly well. For width, there is a limit….and 5" wouldn't be a bad place to stop. They would be plenty strong. Also cosider you could put in 2 tenons not lengthwise, but side by side in 2" stock. I'm not suggesting you do but it would be possible. There will be some other opinions on how to do it, and you can pick and choose what works for you.


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## HorizontalMike (Jun 3, 2010)

> Traditional rule of thumb is tenon is 1/3 of stock thickness inset the same distance on the edges. For thin stock use 1/4-1/2-1/4 ratio. (1/8-1/4-1/8 for 1/2 stock etc.)
> 
> Tenons are strong vertically, pretty strong laterally but weaker against pullout. Add pins if pullout is expected to be a major issue. Knock down tenons can be wedged.
> 
> ...


+10 on all of the above!

I really love loose tenons, as I find them to be the most forgiving.


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## MarkShultz (Nov 9, 2011)

Thanks guys I've seen those rules, including the rule to not go over 4 or 5 inches in width, which are what I used above. However, one additional rule commonly cited on the web says that tenon width should not be more than 5x thickness.

Tenon rules (which cite the 5x rule): 
https://www.popularwoodworking.com/chris-schwarz-blog/tenons-rule-so-here-are-the-rules-on-tenons/

https://robcosman.com/pages/newsletter-article-mortise-and-tenon-joints


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## wapakfred (Jul 29, 2011)

I don't worry to much about the 5x regarding the width of the tenon, but if it makes you feel better, cut them into 2 tenons (and glue both). Re read Schwarz's last sentence in that link….it's enough to make your head swim.


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## rwe2156 (May 7, 2014)

Double tenons on the 8.5" rail. 1" gap between and 1/2 - 3/4" shoulders.

I would seriously consider pinning them, too.


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