Threading Blind Holes
There are three accepted methods of threading blind holes:
- Conventional tapping, especially with bottom taps
- Single-point threading, where the workpiece is rotated, and a pointed cutting tool is fed into the workpiece at the same rate as the pitch of the internal thread. Single-pointing inside a blind hole, like boring inside one, is inherently more challenging than doing so in a through hole. This was especially true in the era when manual machining was the only method of control. Today, CNC makes these tasks less stressful, but nevertheless still more challenging than with through holes.
- Helical interpolation, where the workpiece remains stationary and CNC control moves a milling cutter in the correct helical path for a given thread, milling the thread.
Read more about this topic: Blind Hole
Famous quotes containing the words threading, blind and/or holes:
“Those Maine woods differ essentially from ours. There you are never reminded that the wilderness which you are threading is, after all, some villager’s familiar wood-lot, some widow’s thirds, from which her ancestors have sledded fuel for generations, minutely described in some old deed which is recorded, of which the owner has got a plan, too, and old bound-marks may be found every forty rods, if you will search.”
—Henry David Thoreau (1817–1862)
“There is nothing more poetic and terrible than the skyscrapers’ battle with the heavens that cover them. Snow, rain, and mist highlight, drench, or conceal the vast towers, but those towers, hostile to mystery and blind to any sort of play, shear off the rain’s tresses and shine their three thousand swords through the soft swan of the fog.”
—Federico García Lorca (1898–1936)
“The danger lies in forgetting what we had. The flow between generations becomes a trickle, grandchildren tape-recording grandparents’ memories on special occasions perhaps—no casual storytelling jogged by daily life, there being no shared daily life what with migrations, exiles, diasporas, rendings, the search for work. Or there is a shared daily life riddled with holes of silence.”
—Adrienne Rich (b. 1929)