In our case, the correct tap drill would be the closest to 3.4 mm from below, and that is the 3.3 mm or 0.13-inch tap drill. An assortment of screws, and a US quarter for size comparison. A rule of thumb is that the right tap drill is around 85 for coarse threads and 90 for fine threads which feature a higher number of threads per axial distance. Choose from our selection of 1/2'-13 helicoils in a wide range of styles and sizes.

Then turn the tools counterclockwise with pressure to extract the insert. Thread Calculator and Chart for metric thread, npt thread, bsp thread, unf thread, unc thread, acme thread, bspp thread, un thread, bspt thread, pipe thread, stub acme thread and buttress thread. helical ridge, called a male thread (external thread). Place the tip of these tools into an insert and strike a light blow to the tool’s head. For over 30 years Harvey Tool has been providing specialty carbide end mills and cutting tools to the metalworking industry. HELICOIL PLUG TAP Drill 17/64,Jugenheimer Industrial Supplies, Inc.