Assembling a Standard Ferrule Connector 1. Slide the compression screw onto the tubing end (see Figure 2-4). Slide the ferrule onto the tubing with the broad end of the taper toward the screw. 2. Push the tubing all the way into the fitting body until the tubing bottoms out. The fitting body can be a stainless steel union, a column end, or any part of the system that has a female receptacle. 3. While you hold the tubing securely in place (bottomed out), finger-tighten the compression screw. 4. Using a 5/16-inch wrench, tighten the screw an additional 1/4-turn. This seats the ferrule against the tubing and prevents it from coming off when you disconnect the tube. 5. Remove the assembled fitting and verify that the length of tubing extending beyond the ferrule is equal to the length of tubing of other fittings previously installed.