Dado Joints with Mechanical Fasteners

[John Hollaway]

I need to construct several 2-foot-wide, 12" deep, built-in jelly cupboards. While the face frames and doors will be red alder to match the walls, I've been asked to construct the carcass from 3/4" melamine for brightness and cleanability. The shelves will be fixed and glued into dados. For several reasons I'd like to reinforce the glued dados with a mechanical fastener installed from inside the cupboard. Perhaps several brads shot on a 45 through each dado joint from beneath each shelf would suffice. I originally considered dowels or confirmat screws through the sidewalls, but would prefer not to go that route. Maybe somebody here has a different idea. Thanks.

John Hollaway

[John Schweikert]

Kreg pocket screws. Have shallow dados 1/8" is all that's needed, adjust the Kreg screw depth slightly, screw in underside the shelves and fill the holes with their plugs.

[Rod Sheridan]

John, I think a cabinet that small, that's attached to the building doesn't need anything more than a dado and glue.

Why complicate things?

Regards, Rod.

[John Hollaway]

John, thanks for the Kreg idea. I should have thought of that myself.
Rod, remember, we're talking about melamine, so not much glue surface. And, the carcass will be assembled in my shop and moved to another location in the house to be built in as a unit. I'd hate to bump something solid during the move and knock a joint loose. Perhaps a bit over-cautious, but the old "ounce of prevention . . ." adage has nailed me a few times over the years.

[Jim Andrew]

The shop I worked at used lots of that board, and they did use one brad into the shelf along with glue, but it was to hold the box together while it dried. They stapled through a t&g joint holding the face frames on, also glued. No problem with boxes coming apart while hauling and delivery. Never heard of a box coming down from the wall either. they used 1/2" thick material for boxes. The glue holds well on the ends of the shelves in the grooves.

[Peter Quinn]

If the sides are blind I'd do it all from the out side, don't need confirmats or dowels, plain old #8 assembly screws or hi-lo's ( dual pitch thread made for chip board sold at most home centers) work just fine to hold the joints while glue dries. Problem with melAmine is the glue truly is stronger than the wood...because the wood is pulp. A little mechanical reenforcement doesn't suck, I would not consider putting any fasteners from the inside unless that was the only choice, looks like craftmade Home Depot cabs that way, best avoided ImO. The back will in most cases stiffen the case, I have seen melamine joints crack on tall boxes with minimal internal support.

[Jamie Buxton]

"built-in"? So the outside of the carcass is inside a niche? If so, yeah, fasteners in from the outside. I do like confirmats in chipboard. Staple the back on.

[Robert Engel]

If you use Panolam instead of Melamine you'll be able to have a stronger glue line if that's the big issue.

If there's an exposed end panel you'll be covering it with wood, right?

So why can't screw form the outside?