threaded insertthreaded insert.

What are the terminology used in screw threads?

Screw Thread Terminology

  • Root.
  • Crest.
  • Flank or side.
  • The angle of the thread.
  • The depth of thread.
  • Nominal diameter.
  • Major diameter.
  • Minor, core, or root diameter.

What does it mean to thread a hole?





Tapping a hole is the process of creating threads on the sides of a drilled hole to enable screwing in a bolt or machine screw.

What is the thread terminology?

Pitch – Pitch of a thread is the distance between 2 crests. Angle – The thread angle of a screw is the angle between the threads. Crest – Crest of the thread is the top part of the grove that corresponds with the majr diameter. Flank – The flank is the angle at which the helix is raised to form a crest.

What does UNC stand for in threads?

Unified National Coarse Thread

UNC – Unified National Coarse Thread, comparable with the ISO metric thread. UNF – Unified National Fine Thread.

What is the meaning of a bolt hole?





a place of escape or refuge

Definition of bolt-hole
chiefly British. : a place of escape or refuge.

What is counterbore hole?

A counterbored hole is essentially a pilot hole consisting of a long and narrow threaded channel at the bottom and a shallower but wider channel at the top. The latter channel supports the head of a counterbore screw. If you inspect a counterbore screw, you’ll notice that it has a flat head.

What is UNF and UNC thread?

There are two main kinds of threads in the Unified Screw Thread (UST) Standard—UNF and UNC. UNF is the designation for Unified Fine Threads. Meanwhile, UNC denotes Unified Coarse Threads. UNC threads are a type of coarse thread that has an unbroken series of right-hand turns with uniform geometry.

What is the difference between UN and UNC threads?



UNF threads are Unified fine pitch threads, while UNC threads are Unified coarse pitch threads. UNF and UNC thread screws are both used for fastening, but mainly applied in different fields. coarse thread has higher strength and find thread is better for sealing.

What is Nef thread?

NEF ( national extra fine)

Size. Threads per Inch. Major Outside Diameter. 1/4″

What is a coarse thread?



Bolts with coarse threads have a larger pitch (fewer threads per axial distance) compared to fine threads. A coarse threaded bolt is specified for most applications unless there is an overriding reason to use a fine threaded bolt (e.g. thorough thread adjustment is crucial for the application).

What does NC stand for bolts?

Common Fastener Related Abbreviations

Abbreviation Meaning
NC National Coarse Thread
NF National Fine Thread
NT Nut
OH Oval Head

What is national coarse thread?

The Unified National Coarse (UNC) is a defined standard set of thread forms, sizes, and other variables commonly used in the United States and Canada. Coarse threads are deeper than fine threads, with fewer threads per inch on the tool.

What is NC and NF threads?

NC and UNC mean coarse thread. NF and UNF mean fine thread. NS means special thread. Pitch Diameter is the basic dimension of a screw, threaded hole, or a tap the diameter of an imaginary cylinder, the surface of which passes through the thread where width of thread and space between threads are identical.

What does D5 mean on a tap?



Tolerance Chart – Metric Coarse / Fine

Metric Coarse Thread Pitch Tap Tolerance
4H Tap
M 45.0 4.50 D5
M 48.0 5.00 D5 / D6
M 52.0 5.00 D5 / D6

What is the difference between NPT and NC?

UNC is Unified Coarse thread , the successor to the obsolete National Coarse (NC) thread. UNF is Unified Fine thread, the successor to the obsolete National Fine (NF) thread. NPT National pipe thread is used (in the U.S.) for plumbing of water and gas pipes, and threaded electrical conduit.

What does NS stand for on a tap?

SUMMARY. The American National Standard has been obsolete since 1949 and replaced with the Unified National Standard. In all cases, the threads made to the Unified National Standard are designed to screw together with the obsolete American National Standard.

Is Sae the same as UNC?

There are two general types of SAE bolts (sometimes referred to as machine screws). UNF (fine thread pitch) has more threads per inch than the same diameter bolt in the UNC (coarse thread pitch). Nut dimensions are maximums per SAE. Washer dimensions are for the regular size (vs.