I need to cut a few hollow core doors in half. Any tips or tricks to get a smooth cut? My table saw is not big enough so I will be using a circular saw.
TIA,
Jim
That's going to be difficult without tearout, but I'll say what I'd do.
1) Run a wide strip of blue painter's tape around the door.
2) Pencil in two very fine lines for my cut all the way around the door, with one on each side of the blade's kerf
3) Set up a steel straightedge, and score with a utility knife along both edges of the kerf. This is the most tricky part. n.b. if your knife mark is on the waste (kerf) side of the line, it will serve no purpose. If you err a tiny bit towards the good (door) side, then chips will likely tear up to the line, but it will at least help limit the depth of the tearout. So, basically you want to score two lines, just a tiny bit farther apart than your blade kerf. Keep in mind here that the opposite end of the door will have a tiny bevel, and you don't want to end up with a sharp edge, so bumping your knife out say 1/64" to each side of the saw kerf should be just about right. Later, a swipe or two with a plane to knock the corner off should make all this disappear.
4) Cut each side INDIVIDUALLY. So, set your circular or table saw blade depth to just over 1/8", so that each cut only just clears the full thickness of the door skin.
Do not attempt to cut through the door in a single pass! And do not cut through the wood at the top and bottom of the door (or either side, as I'm not sure which way your cut will run) until the skin is cut.
The reasoning behind the last step is that a circular blade set very high will come down vertically on the wood, causing the most tearout. A very low blade will rake out at a flatter angle, tearing less. And leaving the ends of the door intact will keep the kerf from moving as you make the cut.