Using a bandsaw, I make two opposing cuts about 0.250 in. in from the plastic piece's edges. I then push the gage pins into the cuts, which hold them securely. One cut holds the go pin, while the other secures the no-go pin. If the pins are larger than 0.100 in. in diameter, I enlarge the ends of the cuts by working the saw blade back and forth. Drilled holes in the plastic also work.