Cut small angled piece vs mortise and tenon joint?

[Captain Smollett]

I THINK I know the answer to this, but wanted to get some input before I start hacking rather expensive mahogany.

This is for the trim around the aft end of the sea hood, which is the visible portion when in the cockpit or climbing down the companionway.

The old piece seems to have been a solid piece, cut to shape, but that over time broke near the 'elbow.'  It broke along the grain, on both sides.

So, my question is, would it be 'better' to make the little vertical projections as separate pieces and attach to the main (horizontal) piece using joinery?

1000 words worth of picture below.

If you say "joint," which joint would you use?  There far to little room to use a scarf.

I'm leaning toward joining with a mortise and tenon.  I don't want them to break again, and it just seems to me that solid piece is weak.

Grain direction is horizontal in the pictures, left-right; the first is a 'solid' cut piece and the latter uses two separate pieces joined with a M&T.

The little projections are 1" wide, about 2-1/2" tall (though not shown in the picture, they flare back out on the bottom) and are about 1/2" thick.

[CharlieJ]

Two choices-

Miter that corner and use a biscuit( which won't swell with epoxy but will still give support)

Or

Make as shown and dowel it. Could also use a slip tennon instead of dowels.

[Captain Smollett]

Make as shown and dowel it. Could also use a slip tennon instead of dowels.

I think you mean run the dowel through the tenon (ie, both pieces, perpendicular to the face of the wood, not "IN" the joint we often think of a dowel joint), like shown below. Is that right?

I was thinking about that.  Or, since it needs to be screwed to the sea hood anyway, is there a plus or minus in simply running a screw through the tenon?

The previous piece had a screw lower down on the vertical piece (which I would include as well, to keep the bottom from popping 'out' from the sea hood).

It's not really structural, but it obvious gets enough stress (perhaps wood movement from humidity changes or natural flexing of the boat) to have broken the old piece.

[CharlieJ]

A slip tenon is a flat piece of wood, generally rounded onthe edges, used like a
Regular mortise and tenon, but put into a mortise in each piece. Think of an elogated biscuit.

They can be cutwith a router easily.

Since I have a biscuit joiner,'that's what I'd use.

[s/v necessity]

I'm not sure, but I think Charlie is assuming that you will be repairing the old pieces.  He is saying to cut a mortise in each and then insert the tenon.  If you are making it entirely from scratch I think you have the right idea.  Consider offsetting the tenon towards the inboard side, so that you have more material to the outside, and and make it a bit longer than what you have imaged.  (take this with a grain of salt though, I'm not totally 100% sure I understand what you are trying to do, I don't have a grasp of scale for example.)

[Gary Guss]

How about a 1/2 lap joint, lots more glue area, easier to cut than a mortise and tenon

[Captain Smollett]

I'm not sure, but I think Charlie is assuming that you will be repairing the old pieces. 

Ah, yes, sorry for the confusion.  I am making new pieces; the old ones are shot, split, broken and ugly.

I don't have a grasp of scale for example.)

The piece are 1/2" thick, and the 'narrow' piece (the vertical one) is only 1" wide.  It's a pretty small piece, and I can see why the originals broke the way they did.

How about a 1/2 lap joint, lots more glue area, easier to cut than a mortise and tenon

Another excellent suggestion; the lap joint would be easier to cut, but aren't they quite a bit weaker than M&T's?  My understanding is that the M&T is pretty much the strongest basic joint (with variations like biscuits, and dowels and such).

Now, is the strength of the M&T more than needed, so that I am overengineering? Perhaps.  I just REALLY don't want to have to redo this project in the 'near' future.

[s/v necessity]

I like the suggestion of a half lap, it's easy and should be stronger than the origional arrangement.  Considering that this is trim, whatever joint you want to use will probably suffice (is it backed structurally by the hood it's attached to?)  If the half lap comes loose, it'll be pretty darn easy to scrape the old glue off and stick it back togeather.  Dowells and biscuits not so easy...  I think a M&T is the superior way to go, but that assumes the M&T fit properly and doesn't have a bunch of slop, etc etc.

Split the difference and do a finger joint!  That would be easy if you have access to a table saw.  Perhaps the deciding factor here should be what equipment you have at your disposal?

[Captain Smollett]

Perhaps the deciding factor here should be what equipment you have at your disposal?

Right now, have access to a pretty well appointed shop...table saw, drill press, router, hand saw(s), chisels, etc.

Deciding factor is my ability to use them.   ;D

I feel fairly comfortable doing half laps and any of the variation of the M&T (dowels, slip tenons or even biscuits...I have a friend who just bought a biscuit joiner if I decide to go that route).

We've answered the basic question, I think...don't just cut it to shape.  Use joined pieces.  That was my starting point, since it impacts the size of the blank(s) I need to mill.

(I have several sleepless nights to ponder WHICH joint I prefer to use...haha).

Thanks bunches to all who responded!!

On edit:

I thought after hitting "post" above that I could do the half-lap with the smaller piece UNDER the main beam...sandwiched between the main beam and the sea hood itself.  That would be PLENTY strong and I can still screw right through the joint.

It will also hide the joint if I am "off" a little on my fit...