Joinery - Spirit Level

It is possible to detect winding in a surface with a spirit level lithe table were to be tested, the end would be made level by putting a small wedge under whichever leg required raising; this would be seen on looking at the “level” (spirit level), which would lie on the table near and parallel to the edge of the end. The level would then be placed near and parallel to the edge of the front, and this side made level by raising the leg. When this has been done, if the level be placed across the other end it will show whether the corner is too high or too low, or level; if it is level, the table is without winding; if is too low, a straight-edge laid diagonally would touch the table, and not at the two corners; but if d be too high, the straight-edge would rest upon the corners, but would not touch.

When using a spirit level, care must always be taken to see that the under side of the level, as well as the object to be tested, are clean and free from dust, etc. also, after noting the position of the bubble, the level should always be turned end for end and the testing repeated in the same place. Spirit levels are seldom absolutely correct, but by reversing the level an average for the error can easily be taken, and a true level obtained for the piece of work.

To return to the box. The amateur, having tested his board with his straight-edge and also by sighting, and having planed the high places till the surface is true and without winding, he must plane one edge straight, and at right angles or “square” to the side he has finished. He will test it for being straight in the same manner as when he made his straight-edge out of his ruler; but, in order to be able to plane it at right angles to the flat side, he will require a square. As he does not possess this tool he will proceed to make one for himself, sufficient to answer his purpose.