I got a call back from Dubro today. It appears that the information on the Tower Hobbies site is either misleading or down right incorrect. Dubro makes a 2-56/4-40 and the ball bore is sized for a 2-56 machine screw. It is not .112" as noted in the tech notes on the Tower site for the 2-56/4-40 link. As I stated above, you can drill out the shank on a 2-56 link or buy the 2-56/4-40 link.