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Thread: Clamping/glue-up dilemma

  1. #1

    Clamping/glue-up dilemma

    I'm trying to glue-up a frame that is 35 x 20 x 3 (inches) The joinery is dovetails. I put clamps on the length first, then the sides, so the pins and tails are proud and tight. Now for squareness. This is the problem. I put a clamp on diagonally and square opposite corners, but the other two are not. So, I switch corners and the opposite happens. Going back and forth to square all four corners. There must be an easier way? I have one more to do, but this one is 5" high. The glue I'm using has a long open time. Any suggestion would be geatly appreciated. Thanks

  2. #2
    Use clamping squares. You can make your own or purchase them.

  3. #3
    So, should I glue-up two sides and the other two sides separately, then the whole thing or all together?

  4. #4
    Join Date
    Oct 2008
    Location
    Columbus, OH
    Posts
    3,063
    Hi Ron,

    I would glue up all 4 sides at once like you are describing so that all 4 corners cure in a "square" set. When I glue up a frame, or any box, after setting the clamps on the sides, instead of trying to square the individual corners, I measure across the diagonals (corner to corner) and use a clamp on the long diagonal to squeeze it down until the diagonals are the same length and leave it there for the cure. This squares the whole frame all at once. This technique depends on some geometry - if the diagonals are equal and the opposing sides are the same length, the shape must be a rectangle with square corners.

    In your case with pins/tails proud, I would measure diagonals at the inside corners, not the outside to avoid any variances in the cut of the pins and tails. If the corners aren't square after making the diagonals match, the only thing I can think of would be that 1 of the sides is shorter than it's opposite, essentially creating a trapezoid.

  5. #5
    Thank you. It makes perfect sense now. I cut the pieces to length using a cross-cutting sled; however, the sled wasn't wide enough to have a guide block to insure the same length. So much for a pencil line and bi-focals. I'll have to make an extension arm of some kind.

  6. #6
    Join Date
    Sep 2009
    Location
    Atlanta, GA
    Posts
    6,392
    Quote Originally Posted by Brian Tymchak View Post
    ........ When I glue up a frame, or any box, after setting the clamps on the sides, instead of trying to square the individual corners, I measure across the diagonals (corner to corner) and use a clamp on the long diagonal to squeeze it down until the diagonals are the same length and leave it there for the cure.....
    Bingo



    101010
    When I started woodworking, I didn't know squat. I have progressed in 30 years - now I do know squat.

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