Things You'll Need:
- Pencil
- Scrap wood pieces
- Saw
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Step 1
Build a cutting base to stop the piece from sliding during the cut:
In the picture, you can see a support board that I have mounted to my miter saw. It has a base and back fence. I made this from scrap pieces of wood, and screwed it to my saw from the back side of the metal fence.
This has two functions:
- It extends past the end of the saw to better support the piece.
- The wood surface grips the piece much better than the stock metal surface of the saw and stops it from sliding during the cut. -
Step 2
Add a "zero clearance" board to your saw:
The board shown in the picture is tack-nailed (or clamped) to the cutting base, then cut off. The end of this board is now exactly at the place the saw blade cuts. Line up all your cuts to this board, as opposed to the saw blade itself, or a laser line that may not be perfectly aligned.
In this example, the cut is at 90 degrees. This also works very well for angled / miter cuts. -
Step 3
Mark the piece with a V, not a line:
A lot of inaccuracies come from bad marks. If you mark a board with just a line, its not going to be perfectly straight. When you go to cut, you can easily line up to the wrong end of this kind of mark.
A "V" mark, shows you exactly when you are supposed to cut. It also helps you to repetitively line up your pieces to the zero-clearance board. -
Step 4
Line up the V and the zero-clearance points:
When the "V" mark and end of the zero-clearance piece are aligned, you know you are going to get an accurate cut. Make sure you are looking straight-on when you line these up. If you are standing to the side, you will be a bit off due to parallax error (see Resources below).
When you are making the V marks, orient them so they will be on the side of the zero-clearance piece. If they are on the other side, you gain more chance for error. -
Step 5
Cut the piece:
Hold the piece firmly when you cut, keeping your hands six inches or more away from the blade. I grip both the piece and support board, holding these together. This stops drift during the cut, which can come from saw vibration.
Look at the saw blade at all times when you cut (wear safety glasses). This increases safety and helps you to see if your pieces has drifted. If you are still getting drift, clamp the piece. I try to avoid clamping, since it adds a lot of time to each cut you make, but sometimes its needed (very long pieces for example). -
Step 6
Other options:
If you are going to cut a lot of pieces to the same length, use a stop-block.
If you need two pieces exactly the same length, clamp or tape them together and cut them at the same time. Trim one end, then accurately cut the other.
