After having cut all of the pieces of a cabinet it is time to dry fit them together and check how well everything fits together. Now it is time to determine if the cabinet is square.
Note: This technique applies to any box you are building from a cabinet to bed frame.
There are several ways you could check for the box to be in square.
- Place a carpenter’s square on the each of the corners. Check along both sides of the square to verifying that there are no gaps between the square and the cabinet sides. This will work for small boxes, but it does not size up well.
- Take advantage of the 3, 4, 5 triangle. Remember back in school you learned about a triangle that will always has a 90 degree base. The beauty of this technique is that is scales to any size from a cabinet to laying you a foundation forms for building a house. From a corner measure three units one side and make a mark. On the other side measure four units and make a mark. Now the distance between the marks will be five units if the corner is 90 degrees. The units can be inches, feet, centimeters, meters, or whatever unit you want to work in.
- Measure diagonally across the cabinet. The two measurements must be the same for the case to be in square.
Take the diagonal measurements. If the cabinet is square they will be the same. If not, calculate the difference between the two measurements. Divide this number in half. On the diagonal measurement that is the longer of the two push the corner of the box over to shorten the diagonal measurement.
It is pretty easy to do on large box that are not tightly clamped together. However, on a smaller box that is being held together with clamps, the clamps are not going to yield enough to allow the box to move to get into square. What you need to do is put a clamp on the long diagonal and apply some pressure to reduce the length of the diagonal until the case is square.
In the next post I will present a simple adapter that will allow any flat faced clamp to clamp onto a corner without damaging the corner.
