mortise and tennon joint for seats... details pls!

[Erik]

Hi all

Oh... so so many questions.

how deep should the mortise in the seats be? i will use 3/4" x 1 1/2" material (seems standard.). should i be using epoxy to glue the seats?

Thanks

oh and also... before i oil my gunnels and yolk, and varnish my seats and thwarts, should i be sealing the ends of the wood with epoxy or is the varnish/oil good enough?

[The Gutt Clan]

I would use a tenon up to 3/4" deep, 1" wide and 3/8" to 1/2" thick.

I would guess that epoxy would probably be a better choice. On the plus side, if you are not used to make mortise and tenon joints and if yuo don't have all the fancy jigs and tools, epoxy will fill gaps much more nicely than yellow glue.

[Tom in MN]

Make your shoulder on your tenon as small as possible and still give you plenty of room to cover the mortise. The previous suggestion of a 3/4 in deep tenon is fine, but I would not take 1/4 inch of each side of your tenon because all this does it make a smaller tenon. If you think about it, which would be easier to snap off, a 1 inch tenon or a 1/1/4 in tenon. You could take 1/8 inch shoulder off each side and this would be fine, as long as you cut a good square mortise. I would make my tenon 3/8 inch thick. I always make my mortises first, as it is easier to recut a tenon than to shave a mortise. I use a tenoning jig in my table saw which makes is real easy to shave the tenon down to fit the mortise.

If you do not want to mess around with epoxy as a glue, you can use gorilla glue, it is 100% waterproof and you can use it right out of the bottle. Be sure and lightly wet your surfaces first before adding the gorilla glue. You can also pin your tenon from underneath with a screw or dowel for insurance against the glue failing.

Good luck!

[hoz]

One tip I picked up from "The Woodright Shop": when you measure your M & T's be sure to measure from the same side of the stock every time. In other words lay out the pieces as you will assemble them and then make your measurements from one side only. This insures the M & T's will be equidistant from one face and the stock will assemble flush. .

[Tom in MN]

That may work if you are using only hand tools like that dude on the woodwright shop, but this is 2005 and most use power tools. The problem is you cannot cut from one side, especially the tenon. The depth is set by the height of your table saw blade, or the distance your fence is from the blade if you are using the band saw, or table saw with tenoning jig, to cut tenons. This is going to place the tenon in the center of the wood, because you are cutting the same amount off each side. With regard to your mortise, the center of your mortising chisel, or drill bill, has to be in the center of the wood of you want your two pieces flush once your tenon is inserted into the mortise. If everything is centered, then the wood is flush at the joint.

[hoz]

Thx Tom, I know what year it is. Not all of us are Tool Time Tims or even Norms and some still take pleasure in using hand tools. Layout with a marking gauge and cut T's with a back saw. Drill the M out and square with a chisel.

[Tommy]

If the mortise and tenon are not a perfect fit, use thickened epoxy (sanding dust is fine). This will fill any gaps.

[hoz]

I pinned my joints with a contrasting wood dowel for added strength and beauty. Walnut in ash looks nice.

I made my own dowels by driving and then pulling a split of wood through a hole in a steel plate (actually l part of an old bed frame!) . Cheap, easy and the materials were at hand.

[Tom in MN]

Hoz,

Did you learn that dowel method from the woodwright shop? I saw him doing that while I was waiting on his show to end (couldn't happen fast enough in my opinion) and New Yankee Workshop to come on. I thought, "I would just walk over to my dowel container and pull one out." Cutting tenons by hand is certainly possible, but why? Just to say you did it. Do you milk the cow every morning and light the oil lamp? Did you use a table saw to cut your strips, or rip them by hand? Bead and cove with a hand scraper? Plane the boards by hand? Where does it stop? I prefer just to get the job done and move on and am not quite as nostalgic about the method. I respect your desire to do it your way, but can't resist taking a poke at folks who seem to resist the latest technology. All in fun, don't take offense.

Electricity and carbide steel are the best inventions besides marine epoxy.

[Erik]

Do you pin the joint after the inital epoxy or glue has set, or would you dry fit the joint, drill for the peg and then glue it all in one go?

[mos]

Hoz,

Cutting tenons by hand is certainly possible, but why?
...
I prefer just to get the job done and move on...

Interesting. I find that cutting tenons by hand is usually faster than cutting them with my
tablesaw and tenoning jig. There is a point where the tablesaw becomes faster, but that
only happens when I need to cut more than few tenons exactly the same. I am a
software engineer by profession, so I am comfortable with modern technology. I took up
woodworking with hand tools as therapy for sore wrists from typing. I have quite a few
power tools but still do the small tasks by hand. To me, the really big advantage of hand
tools is more safety, less noise, and much less sawdust.

[hoz]

Tom, you may say "all in fun" but your tone indicates otherwise. I learned how to draw dowels from a book on pioneer crafts. I only make a few at a time as I need. I am glad you have a drawer full, several different sizes too I presume?

Like mos I find it easier and faster to make my seats by hand. I am only making one or two, not production. I don't need to fire up the table saw or buy a tenoning jig.

BTW, if I had a small bead and cove plane set I would do it that way. As it is my next strip canoe will be hand beveled not B&C.

Eric: I drill the holes after the joint is set. But guess it would work either way.

[AlanWS]

Even with power tools, it's pretty easy to measure from one face, and with one setup. One way is to make a spacer, thicknessed to match the tenon plus two saw kerfs. Making two cuts with the same face toward the fence, one with and one without the spacer block, leaves a tenon in register. On a tablesaw, you could also use a similar spacer instead of the middle cutters of a dado set, and with the right zero clearance insert, cut both faces of the tenon at once. Another option is a router-cut mortise on each of the pieces to be joined, filled with a loose tenon to join the two. If the joint is at an angle other than square, the loose tenon is the way to go.

The comment on hand tools may have come off as joking in person, but did seem harsher than was warranted here.

[Erik]

Thanks everyone, and hoz!