Selecting a grain pattern that most closely matches the wood where your pocket holesare located is not the only reason to think about grain pattern when drilling pocket hole plugs. Drilling cross-grain will produce plugs with edges that are more chipped or jagged. It also increases the chance of the plug splitting in half. Drilling the plugs with the grain (like in the example below) will produce cleaner looking plugs and will lessen the chances of chipping.
Also be sure to look at the end grain of your blank. Grain that runs more parallel [====] to the blank will chip less. Grain that runs more perpendicular [ | | | | ] to the blank will tend to chip more.
For the cleanest looking pocket hole plugs drill with the grain and into grain that runs more parallel to the blank.
Set your drill to the highest speed. If you’re using a cordless drill be sure the battery is fully charged. A battery that is wearing down or worn down won’t spin the drill as fast as a fully charged battery and this can cause the edges of your plugs to chip.
Insert the plug cutting bit in the plug cutter guide block until it hits the plug blank, but do not turn on the drill. Slightly raise the drill bit and bring the drill up to full speed. Then gently lower the bit to the blank and start cutting the plug. When the bit first starts to cut the plug it’s important to let the drill control the feed rate. In other words, don’t apply any pressure at this point. Then when you start to feel a slight resistance on the drill bit you can apply very light pressure.