I'm getting ready to order the stuff to make a couple Havana ballpoint pens from CSUSA. On the page for it they list two drill bits, 27/64 and a 35/64. But when I found an 'accessory kit' to use (bushings and bits), it says the bit sizes are 31/64 and 35/64. So what do I need???? I sure don't want to buy one that isn't needed [:I]