I am a new woodworker and have a question I hope you can help me with. I am building a box for 1/2 inch oak. Its dimensions are 5 inches high, 5 inches deep and 9 inches wide. The bottom is a floating panel of 1/4 inch ply in a 1/4 inch groove. The corners are 45 degree miter joints. At this point they are just glued together with titebond original glue. All the corners meet together quite well and their seems to be a good bond.
My question is whether glueing is sufficient or whether I need to strengthen the joints. I am contemplating putting in some “keys” on each of the corners. By that I mean I would cut 3 or 4 small 1/8 inch grooves perpendicular to each corner and install a 1/8 inch piece of oak or some other material, for strength. (I saw this in a book a checked out of the library). The box will be gift to my 22 year old daughter and she will use it for smal personal items, keepsakes etc. It will not recieve much rough use. I would rather keep it as it is but if there is a strong danger that the joints will fail in the next few years I will strength it. (Its to late to put in a splined miter joint.)
Thanks for your help.
Frank
Replies
Dear Frank,
Many small boxes are built like that. Since the box is already built so, if any doubts, it can be tested by applying some stresses with just the hands. If it feels strong it is going to stay pretty much like that.
If there is a weakness, testing it would feel like it's weak. Usually some movement can be felt.
If it feels OK, there wouldn't be need for extra reinforcements, specially for the intended use.
Best wishes.
-mbl-
Some boxes are built this way, the way you've done it, but look at the joinery:
a simple miter is a compromise between end-to-end grain (no strength) and face-to-face grain(very strong). Also since the panel is floating and not glued,there's no strength there. Unless the top fits snugly over the box perimeter, I'd install keys to add strength. It might look good now, but you'd want this thing to last.
Frank,
Since you are gluing end grain to end grain at the corners, presuming the grain in the sides runs horizontally, this is relatively weak construction. This doesn't mean the joints will certainly fail but the chances are very good that they will break eventually.
I would never build a box for a customer with this construction, the risks are too high. Reinforcing the corners with keys as you are considering is a good idea.
John W.
If you want the box to last forever and ever, you should reinforce the joints. If you decide to do keys (and excellent idea) I would suggest you make another box out of scrap, exactly like the one for your daughter, and practice on it first, since it seems you've not done the operation before. Hopefully, the description you read included information on grain direction of the keys relative to the box.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Another proud member of the "I Rocked With ToolDoc Club" .... :>)
On a box that small, you could get additional strength by gluing the bottom into the grooves.
Floating panels are a way to compensate for solid wood movement. They are not usually necessary for small plywood panels.
Regards,
Dan
Frank,
An alternative to the keys if you are reluctant to change the appearance of the outside of the box, would be to reinforce the joints inside with glueblocks. Triangular in section, run the grain same direction as the box sides. Still 45* glue surface (on the block at least), but adds a lot more glue area to the joint.
A more subtle variation to the 1/8" keys is to kerf across the joints in two or three places with your dovetail saw, and insert a slip of veneer into the kerf. Adds a lot of strength without a lot of wood, or effort. Compress the veneer first by hammering it, coat with glue and slide it into place.
Cheers,
Ray
All excellent advice.
Retrofitting strength to a mitred corner is not the best design choice, but needs must. If it's any comfort, I have half a dozen small open (no lid) boxes knocking around in my workshop that are up to 20 years old. Plain glued mitres, bottoms glued in, all holding up well ... BUT the mitres are perfect, and they were made as experiments, not for paying customers (nor to be cherished, lifelong gifts).
If it were me, I'd think about starting over, and making another box with spline-reinforced mitres. Regard the first effort as useful training - keep it for yourself!?
I build 11"x14" picture frames and boxes to hold my grandkids wooden blocks using simple miters.
I don't expect that mitered glue joints on boxes would ever fail.
Frank, I've built way too many boxes in the last 30 years. I have boxes full of boxes. It's an addiction. A few are just glued, some have keys which I always called slip feathers. Don't know where I got that. Later ones are dovetailed. Anyway, here's my thought. If your daughter accidently knocks your box off the dresser to a hardwood floor, and it lands on a corner, it will likely break from the shock. If it has keys near the leading edges, it probably will only suffer a bruised corner. If it's dovetailed she can throw it on the floor and it won't break.
I've only had one glued box to fail. Apparently the wood wasn't dried properly and wanted to cup which opened up the miter at the top. Even at that it didn't fail completely but may in the future.
Good luck,
Ian
Ten years ago I slapped such a box together for my wife from scraps of cherry, thinking it would fall apart quickly. She's been using it ever since.
Thanks so much for all your suggestions. I've learned a great deal on this forum. I haven't decided for sure how I will proceed. Perhaps I'll post a picture when I complete the project.
Frank
Frank,
One method, perhaps it's already been mentioned, that you could use on the existing box is to rout dovetail slots through the corners and insert contrasting color dovetail shaped keys. A couple, nicely spaced on each corner would "jazz up" the appearance and add exponentially to the strength. Good luck.
Regards,
Mack"WISH IN ONE HAND, #### IN THE OTHER AND SEE WHICH FILLS UP FIRST"
Most people underestimate the strength of a plain mitre joint - probably because it was once harder for a non-professional to make a perfect mitre, and because the glues are now much better.
Thin wood (less than say 12 to 14mm), perfect mitre, well clamped and the right glue and you've got a pretty robust joint. Especially if you also glue in an inert base and can add some other help (I sometimes also glue in a mitred or butt-joined slip lining).
Frank
if it makes you feel more confident definitely reinforce the corners with either splines or dovetail keys. However, treat the splines or keys as a decorative feature, by using contrasting timber and thoughtful placement and sizing.
As an ex picture framer I would approach those joints like the ones in my frames and cross nail them. Picture framers brads are longer thinner and have smaller heads than the typical lumber yard variety. We normally drill them partway in with a brad that has a hardened tip for a drill bit chucked into a dremel tool. You harden the tips by heating them to bright red and then quenching them. Then while the freshly glued joint is gripped in the miter vise the nails are driven in and set. Later the holes will be leveled and color blended with wax fillers. This creates a very unobtrusive reinforcement for the joint. I realize that this might not suit your situation but thought t worthwhile to throw out this differing style of work for the general education of readers here. It is a simple and practical way to work with mitered joints, though it does require some specialized brads and equipment (miter vise and dremel tool).
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