Place your pre-assembled railing panel so that baluster spacing is roughly the same on both sides. This means the space between the closest baluster and the post at either end should be equal. Eyeball this at first, then clamp your railing panel in place and take a moment to measure the spacing. Adjust as necessary before you mark your cutting point. Remember, you need a minimum of 1 ¼ inch space for the baluster to clear the bracket.
You will need to use a light-colored marker to show up on the black railing – silver works particularly well.
Local GuidelineSecure your panel to your sawhorse using your clamp, and extend the cut mark you made earlier using your speed square as a ruler. Next, use a circular saw with a wood cutting blade to cut the top and bottom rails at both ends. Remember, the finer your blade, the cleaner the cut. Remember to put on your ear and eye protection before you cut.s
Adding Painter’s tape on the shoe of your saw will minimize scuffs and scratches on the surface of your railing panels.
Finally, you need to cut access holes in the anti-rattle strip at the top of your railing. This is to allow you to fasten your railing to your brackets and posts. If you don't cut them now, you'll have to backtrack later.