Juan Hovey
08-18-2014, 6:02 PM
This bench will either last a long, long time or become firewood soon. The wood is black locust, and as Noel Coward put it (or was it Cole Porter?) the stuff was moister than an oyster - 20 percent, according to my more or less reliable meter - when I started work on it two weeks ago.
What were the risks? Let me count them: warping, checking, splitting, and who knows what else.
Still, the grain on the slabs was straight, so the risk of warping seemed low. Even so, I joined the three boards comprising the top with plenty of glue and 3/4x1 inch splines from the waste. I also cinched the middle board to those on each side with half-inch galvanized lag screws 10 inches long, three on each side, counterbored so that the thread reached as far as possible into the middle board.
I plugged the counterbores with 1 1/4 inch dowels turned from waste, then sealed the end grain of each plug with beeswax mixed with mineral oil. I did the same to the end grain on the top and to the bottoms of each leg of the base.
I took special care in making tenons and mortises for the base rails, making sure to get no-slop fits.
The legs are through-tenoned into the top, and I can tell you that my heart took flight when the top, with only a little help from me and a friend who came by to help, swallowed those tenons with a wondrous "thock."
The cabinets rest not on the bottom rails themselves but rather on crossed slats glued into grooves on the inside top edge of the rails, in hopes that this detail, like the wedged through tenons attaching the top to the base, will limit the risk of warping. I have no idea what the wood is on the cabinet faces.
Warping and splitting are the things I worry about most, and I'm hoping that all of this engineering will work against these risks. Will it? Who knows? If the beeswax and mineral oil seal the end grain, the wood will dry slowly and, I hope, at the same rate throughout the bench. If that happens, the whole thing will cinch up tight as a drum and hard as a rock, and my grandson, now all of eight months old, will inherit this bench from his father and use it long into this century.
If I'm wrong, I'll know soon enough.295087
What were the risks? Let me count them: warping, checking, splitting, and who knows what else.
Still, the grain on the slabs was straight, so the risk of warping seemed low. Even so, I joined the three boards comprising the top with plenty of glue and 3/4x1 inch splines from the waste. I also cinched the middle board to those on each side with half-inch galvanized lag screws 10 inches long, three on each side, counterbored so that the thread reached as far as possible into the middle board.
I plugged the counterbores with 1 1/4 inch dowels turned from waste, then sealed the end grain of each plug with beeswax mixed with mineral oil. I did the same to the end grain on the top and to the bottoms of each leg of the base.
I took special care in making tenons and mortises for the base rails, making sure to get no-slop fits.
The legs are through-tenoned into the top, and I can tell you that my heart took flight when the top, with only a little help from me and a friend who came by to help, swallowed those tenons with a wondrous "thock."
The cabinets rest not on the bottom rails themselves but rather on crossed slats glued into grooves on the inside top edge of the rails, in hopes that this detail, like the wedged through tenons attaching the top to the base, will limit the risk of warping. I have no idea what the wood is on the cabinet faces.
Warping and splitting are the things I worry about most, and I'm hoping that all of this engineering will work against these risks. Will it? Who knows? If the beeswax and mineral oil seal the end grain, the wood will dry slowly and, I hope, at the same rate throughout the bench. If that happens, the whole thing will cinch up tight as a drum and hard as a rock, and my grandson, now all of eight months old, will inherit this bench from his father and use it long into this century.
If I'm wrong, I'll know soon enough.295087