Knots,
I’m getting ready to make a bunch of shop drawers from birch plywood. These will be used often, under load, and not babied.
The fronts are 7/16″, and the sides are 5/8″. I’ll use lock miters to join the front to the sides.
While doing some test joints, I found that I can eliminate the use of a dado blade if I make the ‘dado’ in the drawer front the width of only a single saw blade. The only examples I can find call for a wider dado here.
An example of each is shown in the attached photo.
Is there a drawback from using the joint made this way? Possibly less structural strength? More prone to twisting? Glue surface area, very important here, doesn’t appear to be a factor.
If anyone has experience with this I’d appreciate any input.
–jonnieboy
Replies
FWIW, it seems to me that the dimensions of the pieces are reversed from what they should be. The drawer front is the piece that will receive most of the initial anti-inertia stress from pulling and pushing. I would also make the joint such that the locking "tabs" are of equal size, and as large as possible, since that is the part of the joint that provides the most strength.
For "heavy-duty" drawers, I'm wondering if a different joint might be a better choice. Through dovetails, for example, might take better advantage of the full strength of both pieces. A lot depends on how much weight will be in the drawers, however. That is, how much inertia needs to be overcome when detting the drawer to move.
Ralph,
I would also make the joint such that the locking "tabs" are of equal size, and as large as possible.
I'm thinking that too, Ralph. Look how the outside tabs are really skinny on the miters with the wide dadoes. They seem delicate being that thin.
Maybe the wrong joinery for the job? Hmmm, you could be right about that. I'll mull that one over.
At any rate, it's seems strange to me that one would go to the trouble of using a dado cut on this joint when a single blade pass seems to do the job as well, if not better, given the thicker tabs you get from it.
--jonnieboy
tool for lock miter joints
Usually, routers or shapers are used to create the lock-miter joint in one pass per edge. That is not to say a table saw couldn't be used to create what might be called a lock-lap joint (i.e. without the miter at the corner), however. Assuming a 1/8" kerf from a standard carbide-tipped saw blade, that might work out OK with rather precise positioning.
It would still be a fairly delicate joint for a heavily-used drawer containing heavy stuff, though. Lock-miter joints are common with small tool-chest drawers containing relatively light-weight objects. I would suggest different joinery, or reinforcement of the corners with metal angle stock (aluminum or iron).
Router
Ralph,
I'm making the top three drawers with this single-kerf lock miter. They're shallow and shouldn't be overloaded too much.
I'm glad I didn't go into a sort of production run with all the drawers at the same time. I'll look at other joints for the heavier drawers.
I can't see your previous response from this screen, where you talked about specific joints, but I'll go back and read your recommendation there.
Thanks for the input. I'll let you know how it turns out.
--jonnieboy
P.S. the joints on the top three drawers are sweet.. You run the mating piece in from the end they're so 'lockable.'
Lockable is likeable.
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