Where did all the cracks come from?

[Ron Hitchcock]

We made a father/son project of a cabinet, 70x34x20 with poplar. It was suppose to be just a proto-type mainly because the colour was going to be java. The carcase was dovetailed on all four sides with mouldings covering the tails. It looked so good with the glass doors and drawers that we finished it. Now two years later there are several cracks on all sides from the corners. Wood movement or is it simple the choice of wood. I've attached a picture. Stop being so cheap with the wood, Ron.

[John TenEyck]

Sorry, maybe it's only me, but I can't see anything in your photo. Perhaps you could post a higher quality photo. If your wood was kiln dried and at equilibrium with your shop I can't think of a reason the wood would crack later except due to some construction no-no. Did you happen to have some internal components with their grain running front to back screwed to the sides? That could easily do it.

John

[Robert LaPlaca]

Well I am with John, the picture you posted is pretty low resolution and kind of blurry.. Is the issue Poplar, I hardly think so, assuming it was furniture grade poplar..

A reasonable guess is either a cross grain glue joint, or as previously mentioned a cross grain part that was screwed completely across the 20 inch wide poplar sides without any provisions for wood movement..

[Ron Hitchcock]

Sorry about the picture quality, I took one with the phone in the daylight and it wasn't much better. There are no screws involved, just dovetails, glue and a moulding to cover. I will take a camera over to take a better picture.

[Ron Hitchcock]

The picture has finally arrived. Note the equally spaced hair-lined cracks. Question was the dovetails too tight or something else. This project was simply a carcase with dovetail corners and a partition above the drawers. The back is rabbited pieces of polar spaced with no glue and one screw per board.

[glenn bradley]

Is the trim just tacked on or is it glued across the grain?

[Ron Hitchcock]

Now that's a memory question. The crown is screwed on, the face moulding is glued and nailed and I'm not sure if I just glue the first few inches on the side mouldings. In any event I was consistent, all corners. The side mouldings are only 1/4" thick. So, is this a calamity of errors - wood choice, dovetails too tight and glueing side moulding?

[John TenEyck]

If you glued on the side moldings at both the front and back edges you have your answer. Doesn't matter if you left the center section unglued, once you glued the ends you pinned that side panel to the molding. When it tried to shrink it couldn't, so it cracked to relieve the stress. The proper solution is to glue a couple of inches at the front and either tack nail it at the back or, better yet, screw it through elongated holes from the inside.

John

[Ron Hitchcock]

Thanks for the info. I will remember this in future projects.

[Howard Acheson]

The cracks are caused by the cross-grain molding you used. The sides appear to have the grain running up and down while the molding's grain is running across. The sides will expand and contract across the grain and the molding will try to prevent it. The molding should have be attached in a manner allowed the sides to freely move.