6 and 9
- the shapes of curled chips, which are usually short, are often considered
the most desirable in production.
Arching
– the method in which an endmill approaches the material to be machined. In
arching, the endmill enters the material from the side following a curved
trajectory until it reaches the required width of cut, and then continues the
feed motion linearly. As a result, the load on the endmill gradually
increases, thereby eliminating shock stress. Arching can also be applied when
leaving the material. In this scenario, the endmill moves in the reverse
order, changing its trajectory from linear to curved.
Assy
- An abbreviation for "assembly".
Asymmetrical index
- This is the unequal angular pitch of a milling cutter.
Back taper
- Small reduction of the tool cutting diameter from the front to the rear
along the tool length.
BAHCO
- Swedish company founded by Johan Petter Johansson, inventor of the plumber
pipe wrench. Today, the word "Bahco" is also used as a slang term for an
adjustable pipe wrench.
Ball-end tool
– A ball-nose tool.
Ball mill
– A ball-nose milling cutter. The correct meaning of “ball mill” is a grinding
device for grinding materials into powder.
Barrel
- A barrel-shape milling cutter.
Bird's nest, birds-nest chips
- A clump of entangled metal swarf formed by long unbroken chips during the
machining process.
"Black" and "white" cutting ceramics
– A commonly used classification of ceramic cutting materials according to
their color. Pure alumina-based cutting ceramics are "white," while mixed
ceramics comprising a composition of alumina with titanium carbide are
"black".
Bi-hex
– A term that refers to a tool, key (wrench), or fastener with a 12-point or
12-corner shape. "Bi-hex" is also referred to as "bi-hexagonal" and "double
hex".
Bell mouth
- Constant-velocity joint (CV joint).
Borazon
– A trade name for cubic boron nitride (CBN). Due to its widespread use and
popularity, the term "Borazon" is often used interchangeably with CBN.
''
Bull-nose
– A milling cutter, a replaceable milling head or insert of toroidal cutting
profile.
Button cutter
– A toroidal milling tool. In most cases, a button cutter is referred to as a
mill with indexable round (button) inserts.
Cap
– a replaceable cutting head that is mounted on the end of a tool. In modular
indexable extended flute cutters, this specific component is also known by
various terms, such as the end unit, front end, front piece, end subunit, and
more.
Chip mouth, chip throat, chip slot and chip gullet
- These terms relate to the area of a cutting tool designed for chip flow
during machining. The chip mouth and chip throat are usually shaped holes, and
the chip gullet is a groove. In rotating tools, the terms "chip mouth" and
"chip throat" are more common in hole making, while the terms "chip slot" and
"chip gullet" are used more in milling.
Cobalt chrome – A cobalt-chrome alloy.
Cobalt steel – In the past this definition related mainly to
AISI M35 high speed steel (HSS) but now is commonly used for designating HSS
containing cobalt.
Comb cracks – Cracks that are usually normal at the cutting
edge of a tool, caused mainly by variable thermal loading.
Cotter cutter, cotter mill
– a key slot milling cutter, usually, in an endmill design configuration.
Coupon – A test sample.
Corn (corncob) milling cutter – A milling cutter, mainly in
an endmill configuration, which features the outer surface having a dense but
usually shallow mesh structure. The milling cutters of this type are also
known as scaly mills.
Crest Cut End Mill
- Slang term derived from "CREST-KUT®" end mills; refers to a specific design
featuring a wavy cutting edge, which was initially introduced for high speed
steel milling cutters.
Cubic
– Metal removal rate (MRR) in cubic mm, cm or inches.
Cutter sweep
– In cutting tools with flutes such as endmills, drills, reamers etc., this is
the area of material that is removed by a fluting tool (a milling cutter or a
grinding wheel) at the end of a flute. The cutter sweep is also referred to as
a "flute runout" - not to be confused with the runout of tool teeth!
Cutting corner
- Cutting edge, normally, of turning inserts.
Decking
- Machining the gasket-surface sections ("decks") of an engine block or/and a
cylinder head to assure a required level of flatness.
Die sinking
– In die and mold making, this means machining 3D cavities, especially deep
cavities.
Differential pitch
– The unequal angular pitch of a milling cutter (refer also to "asymmetrical
index").
Dish
– An angular clearance, which is made on an endmill face toward the endmill
axis, to generate a flat surface. A dish is defined by a dish angle - the
angle between the endmill minor cutting edge and a plane normal to the axis. A
dish-concept design is common for endmills. However, flat bottom endmills
feature zero dish angles.
DN ratio
– The product of the diameter of a main spindle bore and the maximum spindle
speed. DN ratio, which is also referred to as "DN number", is often used as a
criterium of high-speed machining (HSM).
Dogbone, (dog bone) insert
– in cutting tools, particularly in parting and grooving ones, a type of
elongated exchangeable insert that has a profile resembling a dog's bone.
Typically, this insert features two indexable cutting edges.
Duplex
– Duplex (austenitic-ferritic) stainless steel.
E-steel
– Electrical steel.
Entering angle
– a cutting edge angle.
Exotics
– Exotic materials.
Facing, profiling, shouldering
– In turning, these terms are used for specifying typical turning operations.
In milling, they are "shop talk" words used instead of the full terms "face
milling", "profile milling" and "shoulder milling".
Feed force
– the component of the resultant (or total) cutting force that acts on a
cutting tool in the direction of the feed.
Feed mill
– A fast feed (high feed) milling cutter.
Fishtail cutter
- A flat milling cutter for machining slots. Normally, such a cutter possesses
a V-shape- or V-neck end. Sometimes, back draft endmills are referred to as
fishtail cutters too.
Flat drill
– Normally, this is a synonym for a spade drill, but it often relates to a
flat-bottom drill.
Flood coolant
- A cutting fluid that is supplied to a cutting zone from outside (externally)
by a low-pressure jet nozzle.
Flute wash, flute washout
- In cutting tools with flutes, this is the non-cutting section of a flute
outside the maximum length of cut also referred to as the flute run-out.
Fluting
– Machining grooves, mainly spiral.
Fly bar, flybar
– A fly cutter carrying two toolbit inserts.
Gamma titanium
– Titanium aluminide.
GDT
– In manufacturing, Geometric Dimensioning and Tolerancing.
Green insert
- A pressed compact insert before the sintering process.
Half hard
– A term that describes the medium-hardness of steel. It is often used to
specify austenitic stainless-steel sheets that have been hardened through cold
work (rolling) rather than heat treatment. The hardness level of stainless
steel can be designated as 1/4 hard, 1/2 hard and fully hard depending on its
level of hardness.
Handed and neutral
– in the context of parting, the term 'handed' refers to a tool (insert) with
a non-zero lead angle. This means that the cutting edge of the tool is not
parallel to the axis of the workpiece being cut off. Depending on the
direction of the cutting edge inclination, a handed tool (insert) can be
either right-handed or left-handed. In contrast, a neutral parting tool
(insert) has a cutting edge with a zero lead angle, which means it is parallel
to the workpiece axis.
Hard carbon
– Diamond-like carbon (DLC) coating.
Hard chrome
- Chrome plating intended for improving the performance characteristics of a
part by increasing resistance to corrosion and abrasion wear. By contrast with
decorative chrome the hard chrome plating is substantially thinner and used
mainly for aesthetic purposes.
Hard tooling
– Custom tooling; also referred to as dedicated or special-purpose tooling.
Heel
– The portion of a tool where the flank intersects with the base. This term is
commonly used in reference to one-piece (solid) single-point tools,
particularly turning tools.
Herringbone
– A herringbone-type milling cutter is usually a solid carbide endmill that
features flutes combining left and right helix angles. Herringbone-type
endmills are commonly used in machining composites, especially carbon fiber
materials, where the left and right helix combination reduces delamination and
compresses the material edges. Also referred to as a compression router.
Higbee cut ("Highbee", "blunt start")
- In threading, an additional cut that removes an incomplete thread at the end
of a thread to provide a blunt thread start.
A thread with a Highbee cut is also referred to as a "convoluted thread".
The Highbee cut can be used in both internal and external threads.
High positive
– A feature of cutting geometry that relates mainly to the rake angle of a
tool. For tools with high positive geometry, the rake angle is significantly
greater than common values.
High speed cobalt
– A high speed steel with significantly increased content of Cobalt (typically
5 to 8%). This steel is also referred to as cobalt steel.
Hipping
– A term derived from the abbreviation HIP - Hot Isostatic Pressing.
Hook, hook angle – A rake angle; as a rule, this term is
referenced to saws and slitting cutters.
Hoopster.
– a specifically designed type of retaining rings that requires a
shallow-depth groove for mounting.
Hundredths, thousandths etc.
- Hundredths, thousandths etc. of a millimeter or an inch depending on a
chosen system of units.
IC
– The inscribed circle of an indexable insert relates to the diameter of such
a circle. Also, IC stands for "ISCAR Carbide" in designations of ISCAR's
cemented carbide grades.
ID, I.D.
– Inner (inside, internal) diameter.
Inbus
– A hex (Allen) key (from Innensechskantschraube Bauer und Schaurte in
German).
Inconel
– Inconel is the trade name for a group of more than 20 metal
alloys made by Special Metals Corporation. When followed by a number (e.g.
Inconel 625), it is a specific material from a family of
nickel-chromium-based high temperature alloys. Without a number following,
Inconel often refers to a whole group of nickel-based
superalloys.
Inox
– Inox steel is a stainless steel. The term "Inox" comes from "inoxydable",
the French word for stainless or inoxidizable.
Inserted-tooth mill
– A mill carrying replaceable cutting inserts, an indexable mill.
Island
– A small area on the surface of a workpiece that is left non-machined
Jo, Jo block
- A gauge (Johansson) block.
Jobber drill
– An all-purpose twist drill, usually of medium length.
K-factor
– In cutting tools, K-factor may stand for the following:
- Cutting edge form factor, which is the ratio of
honed cutting-edge widths measured on a rake face and a flank.
- Specific power factor (or power unit factor).
Usually, this is the power (in kW, hp etc.), required to remove a unit volume
of a specific material (in cm3, in3, for example) by
cutting. However, in some cases this factor is determined in the opposite way,
resulting in material volume to be removed by cutting when a unit power is
applied.
Kordell
- A solid endmill that has a serrated tooth profile, which provides efficient
chip-splitting action.
''
Land
– in cutting tools, this term primarily refers to the width of a specific
surface, such as the face or the flank, or portions thereof. For example, the
"land" often pertains to a small, usually flat area between the cutting edge
and the rake face of a tool that reinforces the edge. Additionally, the land
can refer to the width of the clearance (relief) surface. In cutting tools
with helical flutes, such as twist drills, end mills, or counterbores, the
land typically designates the peripheral width of the area between adjacent
flutes, meaning the width of the tool's flank. U-drill, insert drill – a drill
carrying exchangeable inserts (an indexable drill).
Ledloy, Ledloy steel
- A grade of free cutting carbon steel that is commonly known by its trade
name ("Ledloy" the copyright name of the Inland Steel Company's steel). The
grade designation according to AISI is 12L14, a similar DIN/EN steel is
11SMnPb37 (W.-Nr. 1.0737). To improve machinability, lead is added to the
steel composition. Therefore, this steel is often referred to as Lead Steel or
mistakenly as Leadloy.
Lens
– An endmill with a convex cutting face (bottom) profile that is represented
by the arc of a large-radius circle.
Lollipop
– A spherical milling cutter that features the wrapping angle of a cutting
edge more than 180° (usually 220-240°).
Sometimes, the lollipop cutter is also referred to as an undercutting mill or
a bulb-type (bulb-shaped) mill.
Master (gauge) insert
– A specially selected insert mounted on a cutting tool to measure the tool
dimensions or to check the tool accuracy parameters.
Mic
– a micrometer.
Microtools
– A broad definition of cutting tools that are very small in dimensions: from
miniature to even microscopic. Therefore, a strict quantitative specification
is difficult. In rotating tools, for example, tools with diameter less than 3
mm (.118") are usually related to microtools.
Microtools
– A broad definition of cutting tools that are very small in dimensions: from
miniature to even microscopic. Therefore, a strict quantitative specification
is difficult. In rotating tools, for example, tools with diameter less than 3
mm (.118") are usually related to microtools.
Mill
– Usually, a milling cutter but also may relate to a milling machine tool.
Miller
– a milling machine.
Moly
– Molybdenum [Mo]. Moly has an exceptionally high melting point and is mainly
used as an alloy agent in steel.
Nasty material
– A difficult-to-cut material; often stands for a nickel- or cobalt-based
superalloy.
Nature of tool
– a broad concept that includes both the cutting geometry parameters and the
cutting material characteristics of a tool.
Near-dry machining (also known as near-to-dry machining)
– a machining process that uses minimum quantity lubrication (MQL).
Necking, necking down – Machining a neck or undercut on a
rotary-body-type part such as a shaft, axle etc.
Necked-down endmill
– An endmill with the shank diameter larger than the cutting diameter.
Nirosta
– Stainless steel, normally austenitic.
Nose
– Cutting corner.
Nub (also referred to as "tit")
– in parting, this is the same as a "pip" - a small piece or burr that remains
attached to the center of a workpiece after a parting (cutting off) operation.
OD/ID machining
- Machining external/internal cylindrical surfaces: "OD" refers to "outer
diameter" and "ID" to "inner diameter".
OD, O.D.
- Outer (outside) diameter.
Orange peel, orange skin
– The visually uneven texture of a material surface, which resembles the skin
of an orange. In metalworking, it is often considered as an appearance defect,
although in some cases an "orange peel" may be a specially planned type of
decorative finish.
Parallel land
– The wiper flat of a milling cutter. The term "parallel" highlights that the
land is generally parallel to the machined surface.
Pecking
– Drilling or countersinking with peck feed.
Pic rail cutter
– A milling cutter that is intended for machining the standard Picatinny rail
profiles (male and female). "Picatinny rail cutter" or "Picatinny rail form
cutter" are more common and more of an official description for such a cutter.
Pig
– Ingot. Usually, term "pig" relates to an ingot from ferrous metals.
Pinch machining
- A general name of machining methods for cutting relatively long and
low-rigid parts when a part is simultaneously machined by two opposed cutting
tools.
This method is also referred to as "balanced machining".
Pinch machining is intended mainly for multitasking machines and comprises
pinch turning and pinch milling.
Plunge rate, plungerate
– The feed speed (feed rate) in the Z-axis direction.
Plunger
– A plunge milling cutter.
Plunging
- Plunge milling.
Pocketing – Milling pockets and cavities, specifically deep
cavities.
Porky
(porcupine) – An extended flute (long-edge) indexable milling
cutter
Port tool, porting tool
- A stepped rotary cutting tool for machining a pre-drilled hole to generate a
complex inner shape in one operation with axial feed, ensuring required
parameters of accuracy and roughness. This tool features high concentricity of
stepped cutting edges and is intended mostly for machining hydraulic ports.
Positive insert
– This may relate to two different features of an indexable insert:
1. Insert where the insert bottom face is smaller than the insert top face.
2. Inclination of the insert cutting edge that generates a positive axial rake
of a tool, when the insert is mounted in the tool.
This dual meaning sometimes causes serious misunderstandings.
PH
- Precipitation hardening stainless steel.
Rapid steel
- An obsolete name for high-speed steel (HSS).
Rapid tooling
- A general name for shortcuts of tool making, usually connected with additive
manufacturing (AM) methods.
Ribbing
- In metal cutting, machining ribs, usually by endmills.
Rotabroach drill or simply "Rotabroach"
– A trepanning cutting tool (an annular cutter). The origin of "Rotabroach"
comes from the company Rotabroach Ltd, who started manufacturing and marketing
such tools in the 1980’s.
Round tool
- Usually, rotating solid tools.
Ruthenium, ruthenium grade
- A cemented carbide alloyed with ruthenium.
Sandwich
– A sandwich-structured composite material that features a core faced by outer
layers.
Scalloped edge
– A serrated cutting edge.
Sculpturing
– usually refers to the process of CNC milling 3D surfaces, which is sometimes
also referred to as "sculpture milling". In a broader sense, sculpturing in
metal cutting can also involve methods such as engraving, chiseling, and other
techniques used to shape a surface. Additionally, it can relate to machining
parts with deep recesses, which is commonly known as "sculpture machining".
Segment mills, circle-segment mills
– A general name of profile milling cutters with large-radius cutting edges
such as barrel-, lens- and ovel-shape endmills.
Serrated edge
– Tool or insert cutting edge with a serrated or wavy shape to ensure chip
splitting action that achieves small short segment chips. Serrated cutting
edge is also referred to as "scalloped cutting edge" and "knurled cutting
edge".
Shear milling cutter
– A milling cutter with negative-positive cutting geometry: negative radial
and positive axial rake angles.
SiMo, SiMo iron
– A ferritic ductile (nodular) cast iron, which is alloyed by Silicon and
Molybdenum. It features increased resistance to oxidation in high temperatures
and therefore used mainly for producing parts of automobile exhaust systems
and turbochargers.
Slicing
– Peel milling.
Slocombe (Slocomb) drill
– A center drill.
Slotter
– In milling, this term defines slot milling cutter; however it normally
refers to a type of planing machine tool.
Slotting
– Originally, this term defined a machining process where a single-point
cutting tool moves linearly and piston wise, and a workpiece is fixed or moves
only in linear direction. However, today this term relates more to slot
milling.
Slotting cutter
– Slot milling cutter (see above)
Spanner or wrench
- Both words mean the same: a tool, mainly operated by hand, for
tightening/untightening parts like bolts, nuts etc. or for preventing a
rotational movement of the parts. "Spanner" is more common in UK English and
"wrench" in US English.
Sponge
– a machined metal in porous state
Spotting
- Spot drilling.
Spring pass, spring cut
– an additional pass at the same setting, mainly in turning, boring, and
threading operations. Its purpose is to clean the machine surface thoroughly
and ensure the required accuracy. The need for a spring pass arises due to the
flexibility of the technological system and the heat generated during
machining. These factors can potentially impact the final dimensions achieved
through a regular pass. In turning, a spring pass is often performed by
backing up the tool with reversed feed.
Staggered tooth mill, staggered mill
- A side-and-face disc milling cutter with alternate right- and left-hand
teeth.
Static accuracy
- The accuracy parameters of a component's geometry, which are measured
without load under static or slow-motion conditions.
Step
- Often stands for a STEP-file, a data exchange file, used to represent 3D CAD
objects in a specific format, as determined by ISO standards. As an
abbreviation, "STEP" is derived from "Standard for the Exchange of Product
Model Data."
Superfinish
- This word is often used for the extremely high surface finish that can be
achieved by a cutting tool. The tool may even be referred to as a
"superfinisher". Not to be confused with superfinishing, which is a fine
abrasive machining process!
Sub edge
- A minor cutting edge.
Surface speed
- Cutting speed.
Surplus
– Machining allowance (stock).
Throwaway tip or throwaway insert
- A replaceable or indexable cutting insert.
On shop floors, this term is rarely used and considered obsolete. However, it
continues to be used in the patent practice.
Thrust, thrust force
- An axial cutting force.
TiNite/Tinite
- Titanium Nitride [TiN]. TiNite is a very hard ceramic material that is used
in the protective coating of cutting tools.
Tip-off
– in engraving, the width of the flat tip of an engraving tool.
Titanium beta (β)
– In most cases it is a beta-annealed α-β-titanium alloy, although sometimes
it means a β-titanium alloy.
Tombstone
– in metalworking, a workholding fixture for machine tools, which has several
sides for mounting workpieces to be machined. A tombstone is also referred to
as a tooling tower and a pedestal-type fixture.
Tommy bar
- Tool overhang.
Tool projection
- A short rod, which is inserted into a hand tool, such as a socket wrench,
for using as a lever when rotating the tool.
Tool signature
– refers to both the characteristic cutting geometry of a tool and the
designation used to identify a specific cutting tool.
Torus
– a toroidal milling tool.
Truing
– generally, this is the process of verifying the correct position of a
workpiece or cutting tool and rectifying any detected position inaccuracies to
achieve the required machining precision. However, in the context of abrasive
machining, truing a grinding wheel often used as a synonym of the wheel
dressing - the operation of restoring the wheel to its original shape and
accuracy.
Two-lip endmill
– a type of end mill that has center cutting capabilities and can be used as a
drill. Two-lip endmills are also known as slot drills.
U-drill, insert drill
– a drill carrying exchangeable inserts (an indexable drill).
V-endmill (V-groove endmill, V-bit etc.)
- An endmill (an exchangeable milling head, a bit) with an arrow-headed
cutting profile to produce V-shaped slots and grooves.
Variable lead
– in cutting tools with helical flutes, the same as "variable helix".
Wandering
– in drilling, wandering is a term used to describe a situation in which a
drill deviates from its intended path. This can occur for several reasons,
such as improper centering of the drill or drill damage. Drill wandering can
lead to inaccuracies in the expected results of the drilling process. Drill
wandering is also referred to as "drill drifting".
Waterfall edge, waterfall, trumpet
- An asymmetrically rounded (honed) cutting edge that, when compared with an
edge rounded by radius, has an oval-shaped cross-sectional profile. Depending
on the profile positioning with reference to the rake and the relief surfaces
of a tool, this profile can be "waterfall" and "trumpet" ("reverse
waterfall").
Weldon
- The cylindrical shank of a tool (usually a milling cutter) with one or two
side flats for clamping and driving. This type of shank was originally
introduced by Weldon Tool Co. in the 1920s.
Whiskers
- Whisker-reinforced ceramic.
Whistle notch
- The cylindrical shank of a tool with an inclined side flat for clamping and
driving.
Z-axis milling – Plunge milling.
Zigzag chips – Fanfold chips.