Australian Wood Review – June 2019

82 Australian Wood Review

PROJECT

tool to test whether a carcase is square. But their designs

share the same inadequacy as the pinch rods: after each

adjustment of the assembly, you need to remeasure the

diagonals and compare them, back and forth as many

times as needed until the case is confirmed square.

Retired woodworker James Gauntlett had a clever

solution to the trial-and-error method: instead of

sharpening the beam to a point, he made a chisel-edge

block and mounted it underneath the beam.

The modification allowed him to place the beam on the

assembly and observe the changes in squareness as he

repositioned and adjusted the clamps (photo 10).

This is more superior to other diagonal methods.

The modified diagonal beams are easy to make in a

few steps. Choose a stable, straight-grained hardwood

to make the diagonal strips of 200 x 200mm (photo

11 ). After ripping all the strips on the tablesaw, cut the

chisel-edge blocks out of one of them to about 50° on

the mitre saw (photos 12, 13, 14). Round one end of

the beams to indicate where the blocks are mounted

(photos 15). Finally, ease all the sharp edges and

attach the blocks to the strips with glue and screws

(photos 16, 17).

In use, place the beam diagonally across the face of a

carcase and mark the first diagonal dimension with a pencil

13. Flip the strip end to end
    on the saw to sharpen the
    opposite end.


14. Rip the chisel-edge block
    in half, and cross cut them
    to about 500mm long.


15. A round profile was
    traced on one end and
    then shaped on the
    shooting board.


16. The longest diagonal beam
    featured is about 150cm
    long; use thicker stock,
    25 x 25mm, for example,
    if longer beams are made.
    17. Find the centreline of
    the beam, and screw the
    chisel-edge block with its
    point in the centre.
    18. Apply the same amount of
    pressure of the pointy end
    against the corners of the
    workpiece when marking
    the lines.
    19. If the diagonal lines do not
    overlap, the work is out of
    square by half the amount
    of the diagonal difference.
    20. Stop the clamping
    correction as soon as the
    corner lines up in the middle
    of the two pencil lines.

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