Being able to accurately mark the material you are working with is a crucial component of any project. For projects ranging from large scale woodworking to carving fine details, a wide variety of tools and methods can be used to properly mark material. This tutorial will cover the fundamental concepts and methods that allow for proper marking and lead to successful cuts.
Step 1: Have a Drawing
Before you make any actual marks on the material, make sure you have some basis for those marks. This could be a rough sketch for a medium fidelity prototype, or a CAD drawing with dimensions illustrated. These drawings will be the basis for your marks and ensure that you cut the correct pieces in the correct places for your project.
Step 2: Have the Proper Marking Materials
The ideal tools to use for your marks might vary from project to project, but generally you will need:
A drawing with the sizes and dimensions of what you will be cutting/drilling.
Something to mark with. Try to keep your marking utensil as thin as possible to reduce error when using saws because of the thickness of the mark. A pencil is ideal. If the material you are marking on cannot be written on with a pencil, cover where you are planning on marking with blue painter's tape and mark on that instead.
Something to measure with. Most generally, this will be a tape measure. For finer details, calipers should be used. You can also use a ruler, or the markings on the sides of a T-square or a carpenter square, which can be useful if you need a straight cut that is perpendicular to an edge.
If you are drilling a hole, make sure to be clear and careful about how you mark it. Draw a plus sign, with the intersection of the two lines being the center of the hole, or where you want to drill. Then make a small indent on that mark; for wood, the drill bit or a screw will work. For metal, you'll want to use a punch and hammer. Having these slight indentations can be very useful when drilling holes because the mark created by using a punch or screw can prevent the drill bit from walking, ensuring that the hole created is exactly where you intended for it to be. That being said, it makes more of a difference with metal because wood is soft enough that the bit won't walk too easily.
Step 3: Make Your Mark
When cutting straight edges on flat material, such as wood or sheet metal, it is generally a good idea to start marking by using a tape measure (or calipers for very small pieces) to measure from one edge and then make a small mark on the very edge of the piece. Then, line the angled edge of a carpenter square or T-square over the edge of the piece, and line the straight edge up with the small mark on the material. Use your marking utensil to extend that small mark and create a straight line across the material.
When making more complicated marks, similar methods are used. If you have a cut that needs to be measured from two different edges, use a tape measure and create something like a plus sign where the corner of the cut is (similar to when you mark a hole to drill), where the center of the point is the corner. Then use the edge of a ruler or either kind of square to create the straight lines from that point to the edge.
When done marking, draw an X on the sides of the marks that are scrap. This will help you determine which side of your mark to cut on when you account for the thickness of your blade, and generally which parts of the piece do not need to be preserved.
If you are marking an edge that is not perpendicular, you can use the carpenter square to measure a specific angle. First, press the angled edge up to your material. Rotate the square about the corner labelled "pivot" until the line on the diagonal edge of the square that lines up with the edge of the material is the line labelled with your desired angle. Keep track of how the triangle is oriented to make sure you draw the correct angle. A 45 degree angle can be easily marked by setting the square up against the edge and marking along the diagonal. This is similar to using the square to draw a straight line across a piece, except it's an angled line now.
Step 4: Precautions
Always re-measure two or three times before you cut anything. Also, when you do cut, it is generally a good idea to cut with the blade on the scrap side of the mark; this way, you don't risk taking away to much material. It is always better to have cut your piece a little too long than a little too short; you can remove material, you can't add it.
Because the blade does remove a certain amount of material, it is important to not mark out all of the pieces before you start cutting. Mark and cut each piece one at a time to avoid measurement errors.