2 May 2020 at 11:35 am #659633Stewart PerryParticipant
A quick question about grain orientation for dovetail joints. I would like to make a small box about 8″ long to house a few indicator lights and push-button switches. The ends of the box will be extended by about 3/4″ to form legs – see attached drawing. I plan to join the front and back panels to the ends with dovetails. The top will sit in 45-degree mitres along the long edges, and the bottom of the box would be unseen and remain open for installing the electronics.
The question is about the grain orientation of the end pieces. The normal orientation of a dovetail joint would have the grain of both pieces in the joint running horizontally. In theory this would make the legs susceptible to breaking off (although with 1/2″ walnut I’m guessing this is fairly unlikely). A stronger design would be to have the grain on the end-pieces running vertically. I’ve never made a dovetail joint like this and I’m not sure what the disadvantages are. Mechanically it seems similar to a normal T-shaped mortise and tenon joint, so I can’t see any reason why it wouldn’t work. Any thoughts on how difficult it would be to cut this joint, and how it might look in the end?
Stu - Surrey, UK2 May 2020 at 12:52 pm #659638Colin ScowenParticipant
I made a test piece for a bread bin I am making, and only happened to have some long grain parts left to do it with. Cutting the joinery is more like cutting a mortice than cutting a dovetail, and the tails and pins are weaker because of the grain orientation, so take your time and don’t try forcing the joints together. Watch the grain direction if you do try splitting the waste off. Use a guide block for paring.
There is also not really any end grain / long grain distinction that highlights the dovetail itself, so the joint looks a bit bland.
But, for your part, as long as you can keep the side walls vertical, you should have some long grain to long grain glue surfaces that should help to keep things stiff. Remember, you can always pack a loose joint with shavings / slivers, just mind the orientation.
(Yes, the one I have made is very loose, I only wanted it to check the spacing and the overhang, not for show.)
Colin, Czech Rep.3 May 2020 at 11:16 am #659785Stewart PerryParticipant
Thanks Colin, that’s very helpful. I see what you mean about the lack of distinction between grain orientations in the finished joint.
As the finished project will be right in front of me for most of my working day I would like it to look as nice as possible, so I think I will build it with the normal grain orientations for the dovetails. I have a few ideas about how to reinforce the legs across the grain to allay my concerns about them breaking off, and will go with one of those.
Stu - Surrey, UK3 May 2020 at 12:51 pm #659790Colin ScowenParticipant
If you have a plough plane, or a saw and a router plane, then you could do a couple of with the grain grooves on either side of each leg (or a central groove), and run some inlay down it. Might look quite nice if it matched the top, and you did something similar with the end grain at the top of the legs.
Colin, Czech Rep.
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