HERE WE ARE BORING THE "PREP" HOLES FOR
THE PIN IN A FOREARM. THE FOREARM IS EXACTLY CENTERED IN THE STEADY REST. THE PIN WE ARE USING IN THIS CUE WILL BE BRASS. NOTICE THE PIN IN THE PICTURE. THE PREP HOLES WILL BE BORED, USING SUCCESIVE SIZES OF SOLID CARBIDE DRILLS UNTIL THE HOLE IS ABOUT .005 TO .010" UNDERSIZE. THAT SIZE IS DETERMINED BY MEASURING THE DIAMETER OF THE PIN BARREL.
THIS PICTURE SHOWS THE PIN BEING MEASURED.
THE PIN IN THE PHOTO IS CALLED A "GAUGE PIN" AND IT IS EXACTLY.380", THE SAME SIZE AS THE JOINT PIN WE WILL INSTALL. THE NEXT STEP IS TO BORE THE JOINT HOLE OUT TO EXACTLY .380". WE DO THIS WITH A BORING BAR USING GAUGE PINS THAT ARE SMALLER THAN .380" AND GRADUALLY INCREASING THE SIZE TO .380". IN OTHER WORDS, "WE SNEAK UP" ON THE FINAL SIZE BY USING THE GAUGE PINS.
