Cutting precisely to a line on a miter saw isn’t easy. Usually, you have to make multiple cuts and sneak up to it. My solution is to use this universal gauge block; one cut is all that’s required. The block works for cutting pieces of any length, as long as they’re not shorter than the block itself.
To make a gauge block, you’ll need a straight board that’s long enough to clamp to your saw’s fence. Trim the board’s left end, then clamp the board to the fence. The left end should be about 3″ from the blade, but the exact distance doesn’t really matter. Score a fine line on the fence, precisely at the block’s left end (Photo 1). Cut the board. Save the offcut—this is the gauge block.
To use the block, mark your workpiece where you want to cut it. Place the block on the workpiece and align one end with the mark. Make a second mark on the other end of the block (Photo 2). Remove the block. Place the workpiece against the fence and align the second mark with the line scored on the fence. Make your cut (Photo 3).
If you ever move the fence, you can use the block to put the fence back in its original location. Just lock the blade in the down position and slide the block up to the blade. Adjust the fence so the scored line is flush with the other end of the block. –Charles Mak