2nd Carcass and 2nd time not being square

[Jerome Hanby]

Measuring diagonals is a good way to find out that some of your squares aren't square after all. That information is really discouraging when you payed upwards of four dollars for that square.

[Rod Sheridan]

Measuring diagonals is a good way to find out that some of your squares aren't square after all. That information is really discouraging when you payed upwards of four dollars for that square.

Jerome, thanks for the entertainment, I haven't laughed so hard in a while.....

Regards, Rod.

[Lee Schierer]

I helped a young man make a pair of night tables for their bedroom. He always wondered why I kept telling him to check everything for square throughout the project when we went to make the drawers, it was "check every thing for square"

He figured out the reason when we went to mount the drawers in the openings. They fit first time and the front sat nicely agianst the face frame.

Start from teh beginning to check all saw settings for square. My factory miter gauge was off true 90 by over a degree. Not a problem for most contractors, but it sure matters for cabinets. I keep the following tools, known to be accurate at hand when making projects:

1. Platic drafting triangles - cheap but highly accurate
2. Starret combination square - not cheap but much better than the cheap ones
3. Carpenters square, checked for accuracy, they don't all come that way.
4. Tape measure - for checking diagonals of all glue ups.
5. Beall Tilt Box

[Bill Houghton]

If one diagonal is longer than the other, put a clamp across the longer of the two diagonals...drawing it in until they are the same.

As someone else mentioned, it's critical to check that your components are square and of equal length before applying the diagonal-measurement test. If the top board of a carcass is 1/4" shorter than the bottom one, you can get the diagonals to be equal, but your carcass will be a trapezoid, not a rectangle.

[Danny Thompson]

Hey Guys,

It is suprising to hear that the table saw fence is assumed to not be good enough for accurate rip cuts. . . I have also considered building a crosscutting sled, but have wondered about how long of a sheet I could really get to cut with one. What is the maximum lengths you guys to try and cut with your sleds?

To be clear, a table saw fence is an accurate reference for acheiving accurate/parallel rip cuts. But a table saw fence can not be used to guarantee accurate/perpendicular crosscuts.

A fence only guarantees that the saw blade cuts parallel to the edge of the board that is tracking along the fence, but does not guarantee that the leading or trailing edge is parallel to the blade.

So, if you use the table saw fence as your reference to cut all four sides, the two opposite sides will be parallel to one another, but they will not be perpendicular to the adjacent sides. Your finished board will be a a parallellogram, but not a rectangle.

To guarantee a square crosscut, you must first rip one side, then register that side against a jig with a fence that is adjusted 90º to the blade. The most common examples are a miter guage and a crosscut sled. A crosscut sled is generally more reliable because the fence supports the full width of the board--reducing the tendency for the board to twist through the cut.

I strongly recommend you build or buy a crosscut sled and carefully adjust the fence to 90º. It will transform your work and greatly increase your enjoyment.