Twist drills grab in thin material and drill three-lobed holes and can distort the material where you want it to be flat at the seal. 20mm is a bit small for a Greenlee style punch. Even a cheap one is better than nothing. Drilling holes for fiber optics may seem like a daunting task, but with the right tools and techniques, it can be a surprisingly simple and efficient process. Fix the rack to the ground with expansion bolts. Top installation: Dimensions of four connection holes on the top according to the. What tools do I use to drill clean holes in both the plastic and aluminum enclosures so that the cable glands fit snugly without any gaps? I tried searching for M20 drill bits and thread taping, but couldnt really find anything solid. Edit: Link to datasheet of cable gland:. In general, installing the optical fiber distribution box can be divided into three steps: installing the optical fiber distribution box on the rack, introducing the optical cable into the optical fiber distribution box, and planning the optical fiber path in the optical fiber distribution box. The. Learn how to install a fiber optic termination box step-by-step for FTTH projects.