Cutting by a plunge router on a router table is not that easy as it is said. Personally, this wouldn’t be my first choice either. But if you need to accomplish the plunge cut on a router table, you have to maintain some precautions and steps to get a flawless output. Whether you are a professional or craftsman of a hobby, safety measures, as well as operating capability, are mandatory to avoid any accident and for a smooth cut.
Cutting by plunge router is like a blind operation as you will cut the workpiece by plunging it down into the bit. All the cutting action will remain concealed till the end. So to get it right you have to follow some rules. At first lock the bit depth. Then set the fence, close the gap in between, and put masking tape to do the marking. Then put a masking tape on the table just on the opposite side of the fence marking.
Now put the wood piece against the fence, take a pencil mark the first end of the piece on both masking tape. Do it from the other side as well. These marks are your starting point and finishing point that will guide you to start and stop at the exact position.
Now set the workpiece on the bit and press a little bit to get the desired cut. To make the cut more effectively you can also drill a hole in the workpiece at the starting point. And then put it on the bit, push it against the fence towards the ending point.
Remember a good alignment and a soft start is necessary to accomplish a good cut. Rather than using a straight bit, Use the bit designed for plunging, since most of the straight bits don’t have a cutting edge at the end and are not suitable for plunging. During the process, the fence or the workpiece itself may move. So I would suggest before starting the final cut do some trial version.
Closing thought: Do not forget to lock the bit height before starting the work. Always put on safety goggles while working with the router and router table. Stay aware of your finger during working time. Now fingers crossed! Hopefully, you will get what you want.