Building a laminated top may seem a little intimidating at first. You have a lot of boards to cut and fit together. But you don't have to be a magician to get a solid, tight-fitting top if you know a few tricks. It only takes two steps: laying out the boards so they're compatible with each other and gluing them together to avoid any gaps.
Like drawing and discarding playing cards to get a better hand, the boards in a laminated top need to be sorted for the best fit and appearance. This means checking each piece for crook and bow but also arranging the workpieces so the top looks its best.
crook. The maple boards I used all had a little crook and bow. But when trying to assemble a laminated top, the crook of a board can cause you more trouble than its bow. So I checked for crook first.
Crook is warpage across the width of a board running from end-to-end, see Fig. 1 and the ShopTip below. It can be difficultto
"pull" a crooked board straight. So do you discard all the boards with crook? Well, if there's more than Vs" of crook, I'll cut it into shorter pieces for another project.
Boards with less than Va" of crook can be used — if they've been sorted first. I arrange them so the crooks oppose each other, see Fig. 1. This way when the pieces are forced flat, the crook is canceled. To keep track of the direction, I'll mark an arrow on the board pointing to the crook.
BOW. When you've identified the crook, you can sort the boards to minimize bow. Bow is warpage along the edge from end-to-end, see Fig. 2. Unlike crooked boards, you can usually iull a bowed board straight. hat's because you're straightening the board across its thickness (not across the width).
Here again, arrange your boards so the "bows' oppose each other. I'll put my straight-est boards on the outside to help pull the rest of the bowed pieces straight. Note: While rearranging the boards for bow, remember to keep the crooks opposed.
APPEARANCE. With the pieces sorted for crook and bow, you still need to consider how the boards will look when glued together. Small blemishes will be sanded out when the top is leveled. But for larger defects you should shuffle the boards again.
LABELPIECES. Onceyouhavetheboards arranged for crook, bow, and appearance,
Howmuch crook is there? It's stretch the string from end-to-not always easy to tell. A simple end and tape it in place. Then at way to measure crook is to use the center measure the gap bea string and some tape. Just tween the string and the board. -
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