Evaluate and cut the header rail. Pull the shower door closed and increase your tape evaluate from one aspect to the opposite. Mark the size within the frame header and use your hacksaw to chop it to measurement. Sleek down the raw edge using a metal file.[13] X Study supply https://www.deluxeshowerdoors.com/services/glass-shower-door-installation-in-needham-ma-deluxe-shower-doors/