On Tue, 18 Feb 2020 12:53:56 -0500, John McGaw
wrote:

On 2/17/2020 8:20 PM, J. Clarke wrote:
On Mon, 17 Feb 2020 16:46:21 -0800 (PST), Michael
wrote:

On Monday, February 17, 2020 at 6:37:09 PM UTC-6, Robbie Brusso wrote:
I had planned on using box joints to build the frame of a hanging cabinet
(top, bottom, sides). However, I'm starting to wonder about the weight bearing
ability of the bottom frame member. The tapers of a dovetail would make
me feel a little better but with a box joint I wonder about the
load bearing ability of the bottom member. Thoughts?

Well made box joints will easily hold up the weight and then some.

If it's the bottom, you're loading a glue line in shear. If you are
using a glue that absolutely positively does not creep (which lets out
just about any PVA glue) you might be OK. But that's what dado joints
are made for.


The cabinet will be suspended by what? The top, as in a French cleat or
will there be some sort of support from the sides? Will the weight of the
contents be supported by the sides or will everything be sitting in the
bottom? All of that matters a lot. Personally, I don't screw around and use
dovetails all-round as my preferred method of support is via French cleat
which applies much of its force to the top (and a little to the back and
sides but that eventually gets applied to the top too).
Not the most inspiring piece ever but this is my first try at a wall-hung
display case. It uses half-blind dovetails to join top/bottom to sides:
http://johnmcgaw.com/ww/furniture24.html


Yours made me think of a way OP could still use his box joints -
attach a second bottom or moulding to make it look like it's
trimmed on 3 edges but actually screwed up into the sides
for a little extra strength ? .. might make the box joints look odd
though ... out-of-place ..
John T.