Glossary of Terms used at Industrial Nut Corp.

Select the first letter of the word from the list above to jump to appropriate section of the glossary.

A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z

- A -

Allowance
The prescribed difference between the design size and the basic size.
Angled Bottom
Bottom of the slot is angled.
Axis of Thread
The axis of the thread pitch cylinder.

- B -

Bearing Surface Radial Slots
Slots that are milled perpendicular to the axis of the part into the bearing surface.
Body Thickness
A reference dimension measured from the bearing surface to the base of the collar on the top of a part.
Broken Corner
Slight chamfer at slot corners.

- C -

Case-hardened
A process by which only the surface area of the part is hardened to a specified depth.
Case Depth
Depth to which Rc 58 minimum is maintained.
Chamfer
An external angular feature emanating perpendicular to the axis of the part.
Class of Thread
An alphanumerical designation to indicate the standard grade of tolerance and allowance specified for a thread. (see also Thread Fit)
Collar
A circular boss on the bearing surface or the top surface of a nut.
Concentricity
The permissible variation in the location of the axis (exact center) of a characteristic to the axis of another characteristic. The axis of the controlled characteristic must remain within a circular zone of a diameter equal to the concentricity limit.
Core Hardness
The measurement of the hardness of the center of the wall of a part.
Counterbore
A concentric diametric enlargement of a hole for part of its depth which forms an angular, radial or flat surface at the bottom.
Countersink
An angular beveling or flaring of the end(s) of a hole, outer edge of a counterbore, or at the bottom of a counterbore, that does not extend to the OD or counterbore diameter.

- D -

(empty)

- E -

EAU
Estimated annual usage.
External Groove
A circular continuous channel cut into an external feature of a part.

- F -

Face Groove
A circular continuous channel cut into the bearing or top surface of a part.
Finish
The type of coatings, platings or treatments applied to the final product.
Flange
A circular projection forming the outside diameter of a part.
Flange Thickness
The distance as measured from the flange bottom or bearing surface of a part to the top of the flange, including the chamfer or radii.
Flatness
The permissible variation of the flatness of a surface or characteristic.

- G -

(empty)

- H -

Hardness
The property of metals and their alloys relating to strength, elasticity, and toughness and defined as the measurement of its resistance to indentation. Through-hardened parts are typically measured by the Rb, Rc or Brinell scales. Case-hardened parts usually have a hardness specified to a specific depth.
Horizontal Slots on the OD
Slots that are milled parallel to the bearing surface of the part into the OD.

- I -

Induction Hardened
A process by which only a designated surface, usually the bearing surface, is hardened.
Internal Groove
A circular continuous channel cut into an internal feature of a part.

- J -

(empty)

- K -

(empty)

- L -

Lead
The axial distance between two consecutive points of intersection of a helix by a line parallel to the axis of the cylinder on which it lies, i.e., the axial movement of a threaded part rotated one turn in its mating thread.

- M -

Major Diameter
Diameter of an imaginary cylinder that would bound the crests of an external straight thread or the roots of an internal straight thread.
Material
American Iron and Steel Institute (AISI) number for the material being used to manufacture the part (e.g., C12L14, C1137, 316SS, 4140).
Micro
The measurement of the roughness of a surface in microinches of roughness height.
Minor Diameter
The diameter of the threaded or unthreaded primary hole.

- N -

Nominal Size
The designation which is used for the purpose of general identification.

- O -

OD
Outside diameter.

- P -

Parallelism
The permissible variation of the parallel relationship of the top surface diameter to the bearing surface diameter of a part.
Perpendicularity
The permissible perpendicular variation of relationship between the bearing surface or the top surface and the axis of the thread (A.k.a. runout or TIR).
Pitch
The pitch of a thread having uniform spacing is the distance, measured parallel to its axis, between corresponding points on adjacent thread forms in the same axial plane and on the same side of the axis. Pitch is equal to the lead divided by the number of thread starts. (see Thread Pitch)
Pitch Diameter
In thread geometry, the diameter of an imaginary cylinder of such diameter and location of its axis that its surface would pass through a straight thread in such a manner as to make the width of the thread ridge and the width of the thread groove equal. The pitch diameter is located, therefore, midway between the sharp major and sharp minor diameters of a given thread form.

- Q -

(empty)

- R -

Radiused Corner
Slight radii at slot corners.
Round Bottom
Bottom of the slot is rounded.
Runout
The permissible perpendicular variation of relationship between the bearing surface or the top surface and the axis of the thread (A.k.a. TIR or perpendicularity).

- S -

Shape
The shape of the largest outside feature of the part.
Slot
The following types of slots are typical for nuts:

Bearing Surface Radial Slots
Horizontal Slots on the OD Top Radial Slots
Vertical Slots on the OD

Slot Bottom Contour
INC is capable of producing slots with the following bottom contours: Broken Corner, Radiused Corner, Round Bottom, Angled Bottom.
Slot Span
The distance as measured from one slot bottom to the opposing slot bottom of a part with an even number of OD slots.
Slot Width
The perpendicular distance measured between the parallel sides of the slot.
Style
The description of the part as it fits in to a family classification of similar part designs or functions.

- T -

Tap Size
The nominal major diameter as given in the thread designation, of a threaded primary hole.
Thickness
The distance from the bearing surface to the top surface measured parallel to the axis of the part.
Thread Fit
A alphanumeric designation used to identify the extreme permissible limits of the pitch diameter. Standard thread fits for Industrial Nut Corp. would be '2B' for inch threads and '6H' for metric threads.
Thread Handedness
Whether the threads are right-handed or left-handed in orientation.
Threaded Length
The depth to which the part is to contain fully formed threads, not including the tapering off of the thread form for threaded partial holes. For a through threaded part this would equal the thickness of the part.
Thread Pitch
The number of threads per inch for inch threads, or the distance between threads for metric threads. (see Pitch)
Thread Series
Groups of diameter/pitch combinations distinguished from each other by the number of threads per inch applied to specific diameters.
Through-hardened
A process by which the entire cross section of the part is hardened. A minimum core hardness may be specified.
TIR
The permissible perpendicular variation of relationship between the bearing surface or the top surface and the axis of the thread (A.k.a. runout or perpendicularity).
Tolerance
The total amount of variation permitted for the size of a dimension.
Top Radial Slots
Slots that are milled perpendicular to the axis of the part into the top surface.

- U -

Unslotted Thickness
The distance as measured from the bottom of the slot to either the bearing surface (for top radial slots) or the top surface (for bearing surface radial slots) of the part.

- V -

Vertical Slots on the OD
Slots milled parallel to the axis of the part into the OD.

- W -

Washer
A circular boss on the bearing surface or the top surface of a nut.
Width Across Corners
The distance measured between two opposing corners of square, hexagonal or octagonal parts, perpendicular to the axis of the part.
Width Across Flats
The distance between two opposing sides of a square, hexagonal or octagonal part.
Wrenching Thickness
A reference dimension equal to the body thickness less the thickness of any washer, collar or flange on the bearing surface of a part.