title = "Thread Cutting: Tapping, Threading, and Thread Milling"

content = """
Thread cutting produces helical screw threads on internal (nut) or external (bolt) cylindrical features. At Ridgecrest Metalworks, threads are produced by tapping (internal), single-point threading on a lathe, die threading (external), and thread milling on CNC machining centers.

Tapping is the most common method for internal threads. A tap (a hardened, fluted threaded tool) is rotated into a pre-drilled tap drill hole while advancing at a rate synchronized to the thread pitch. The tap drill diameter must be precisely specified—too small and the tap breaks; too large and thread engagement is insufficient. Tap drill size is calculated based on the thread pitch and desired thread engagement percentage (typically 75% for most applications). Higher thread engagement requires more torque and risks tap breakage; lower engagement reduces pull-out strength.

Tap types include hand taps (taper, plug, bottoming—used in sequence for through and blind holes), spiral flute taps (which curl chips upward out of blind holes), spiral point (gun) taps (which push chips ahead into through holes), and form taps (which displace material rather than cut, producing stronger threads with no chips—ideal for ductile materials). CNC rigid tapping synchronizes spindle speed and feed precisely, allowing very fast tapping without using tension-compression tap holders.

Tapping parameters: speed varies by material—75–100 SFM for mild steel, 25–40 SFM for stainless, 150–200 SFM for aluminum. Cutting fluid is essential for tapping; sulfurized oils or heavy tapping compounds are used for steel and stainless. The most common cause of tap breakage is inadequate cutting fluid, incorrect speed, misaligned tap, or attempting to tap beyond the bottom of a blind hole.

Single-point threading on a lathe uses a V-profile threading insert advancing at a controlled lead (feed per revolution equals thread pitch). Multiple passes are made at increasing depths. The final thread profile is inspected with a thread ring gauge (external) or thread plug gauge (internal).

Thread milling uses a helical interpolation path on a CNC machining center to cut threads with a single multi-point thread mill. It is used for large threads, threads in hard materials (hardened steel, titanium), and through-out-of-tolerance situations where a thread is being repaired.
"""

version = "0.0.1"
