Hi there Jesse, Looks like you need more lessons in reading, LOL. The gaps between the links are full of air, called a space. it is through this space that you place your drill bit, these drill holes will come evenly spaced. If you are drilling over a saddle tank or a smoke box, you then get even spaced holes to put the rivets in nice and even. GET IT ? Bob in New Zealand. -----Original Message----- From: Jesse Look Kangaroo lover, but it seems to me that the hardened chain would dull most any drill including solid carbide. Jesse > Pay attention Unk! The chain is used as a spacing jig on curved surfaces > for laying out rivet holes or whatever! > MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.