sizing through tenon help needed

[Michael Hammers]

I posted this in another forum but thought I would try here to see if anyone had any experience with this.

I have glued up my legs and have my stretchers ready on my bench.

My base posts are 3 3/4" thick and 5" wide.

The stretchers are 2 7/8" thick and 6" wide.

So here is my dillema. I want to make a tusk tenon. With a total thickness of 3 3/4" I need to create the shoulder and through piece.

In rules of thirds this would mean the shoulder would be 1 1/4".

So that being the case I would have to again split this in thirds to determine the tusk size which in turn would be close to about 1/2".

Does this seem right? I am worried I do not have enough material to make a viable and strong joint.
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[Eric Hartunian]

Don't worry about thirds for the main tennon. Just give it a small shoulder, maybe 1/4 all around. That leaves more of a tenon to put the tusk in. Of course, that means chopping a much bigger mortise for the tenon, but that isn't a big deal. 1/4 inch shoulder, on that large of a tenon should be plenty of bearing surface for strength.

Eric

[Chris Friesen]

I'm not clear what you're trying to do. Are you wanting to use a tusk tenon on your stretchers, with a mortise in the legs? In that case the shoulder you should be worrying about is on the stretcher, not the legs.

Given your dimensions you could probably make the tenon thicker to give yourself more room for the tusk. Below is a picture of a workbench with vertical tusk tenons...the cheeks around the tusk are fairly thin and it looks like it's held up fine.

http://jointer.oldetoolshop.com/cbench3.jpg

You could also use horizontal tusks as well, but you'd have to pound them in manually as they loosen.

[harry strasil]

all you have to worry about are stops on top and bottom,don't worry about the sides.

[Michael Hammers]

Thanks, I feel much better. I will post some pics next monday after I go to the shop.
The base is in two pieces (trestles) and then two stretchers hold it together.
Each base has the two "posts" that will have the mortise all the way through. The stretcher will go thru this and the be locked via a vertical tusk.
I truly wish I had a simple drawing program for a computer!

[Charlie Mastro]

Thanks, I feel much better. I will post some pics next monday after I go to the shop.
The base is in two pieces (trestles) and then two stretchers hold it together.
Each base has the two "posts" that will have the mortise all the way through. The stretcher will go thru this and the be locked via a vertical tusk.
I truly wish I had a simple drawing program for a computer!

Try Sketchup from Goggle
http://sketchup.google.com/#utm_campaign=en&utm_source=en-ha-na-us-syn&utm_medium=ha&utm_term=sketchup