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)
“man will be blotted out, the blithe earth die, the brave sun
Die blind and blacken to the heart:
Yet stones have stood for a thousand years, and pained thoughts
found
The honey of peace in old poems.”
—Robinson Jeffers (1887–1962)
“But Father John went up,
And Father John went down;
And he wore small holes in his shoes,
And he wore large holes in his gown.”
—William Butler Yeats (1865–1939)