Glossary of Marking Terms

Glossary of Marking Terms

What follows, in alphabetical order is a compilation of terms associated with part marking, identification and traceability.

BACKGROUND OF A CHARACTER: The area from which material has been removed around the raised character of a die.

BAR CODE: The bar code contains reference number data that is associated with computer-stored descriptive data and other information.

BASE OF A CHARACTER: Bottom of the character that intersects the background of the die.

BEVEL: The slant, or angle, from the face of an engraved character to the background is termed the first bevel, or character bevel. The clearance taper, or sighting angle, on the sides of hand stamps is called the second bevel. (on engraved character): The angle of the side wall of the engraved character-usually 45 degrees. This angle is determined with relation to a line running perpendicular to the background and is always the same as the angle on the engraver’s cutter.

BLANK: A piece of steel, brass, or other metal machined to accommodate the characters, design, symbol, etc. to be engraved.

BOTTOMING: Stamping or impressing a stamp or die to the background of characters, design; ironing out upset or metal displaced by the stamping die.

BRANDING DIE, STEEL: Die that can be heated either electrically or in an open fire to sufficient temperature to burn characters into wood, leather, etc.

BURNISHING THE MARK: Rolling back in or flattening the burr which has been raised by lettering tool.

BURR: Material upset or pushed out of the indentation made by the engraved character. If the burr is objectionable it can be removed by grinding, diamond turning or polishing.

CHARACTERS: Single term for either letters or figures. See “Faces” for face types. (See “Styles” for letter styles)

CHARACTER FACE: the stamping edge of engraved characters. A character face may be sharp, flat, round, dotted or open (outline).

CHARACTER HEIGHT: The top to bottom measurement of a character.

CHARACTER WIDTH: The left to right measurement of a character. Refers to the degree to which characters are condensed or extended.

CHARACTER STYLE: Refers to the look or “font” of the character, such as Gothic, Roman, Script and other variations in the appearance of characters.

COINING DIE: A die engraved with sunk characters for the purpose of raising letters or figures above the surface of a soft heavy metal by pressure exerted from a high tonnage punch or coining press.

CONCAVE STAMP: Characters cut on a depressed curved surface to suit a convexity to be marked. (See “Convex Stamp”)

CONDENSED CHARACTERS: Letters or numbers narrower than standard width. Regular condensed characters have a width 50% of the height of character. Extra Condensed Width 40% of height.

CONVEX STAMP: Characters are cut on a raised surface fitted to mark a concave surface.

COUNTERS: A single character typing die (can be letter, figure or symbol) used as a first operation in bench engraving for displacing the metal from the inside of a raised character. After counting it is filed, engraved or chiseled to a finished character.

DATA MATRIX™: The public domain code from RVSI Acuity CiMatrix, is a 2D matrix symbology designed to pack a lot of information into a very small space. The Data Matrix symbology emplys Ree-Solomon error correction with data redundancy to guarantee a fast and accurate read.

DEBOSSED CHARACTER: A sunk impression produced by a pair of male and female engraved dies or type.

DEBOSSING DIES, STEEL: Complete set consists of one pair (male and female) with metal clearance allowed, to sink characters below a stipulated surface.

DIE: Any engraved blank used for marking by means of stamping, rolling, branding, embossing, coining, or semi-coining characters or designs.

  • BRANDING DIE: A metal die that can be heated to a temperature sufficient to burn or scorch characters or designs into nonmetallic substances.
  • COINING DIE: A female, sunk, engraved die used in pairs or with a flat planisher to produce raised characters on surfaces of thick material.
  • DEBOSSING DIE: The same as embossing dies except to produce sunk characters or designs in sheet material.

DIE INSERT: A type die placed in a larger die to effect part numbering, etc.

DIRECT PART MARKING: A method of directly marking the part surface with marking information instead oof attaching a label or tag. Direct part marking offers: permanent part identification, machine-readable codes, aftermarket traceability, and improved “cradle-to-grave” par tracking accuracy.

DOT MATRIX: A character or pattern created by equally shaped and spaced dots.

DOT PEEN MARKING: A stylus, or pin, is fired into the marking surface to make an indented dot. By rapidly repeating this and moving the stylus between each dot, writing and images can be applied. Dot peen marking is also known simply as dot marking, as stylus pin marking and micro percussion marking.

DUROMETER: The hardness of rubber, plastics and other soft and elastic materials.

EMBOSSING DIE: A pair of dies used to produce raised characters in sheet material with a thickness 1/8th of the character size or less.

EMBOSSED CHARACTER: A raised impression produced by a pair of male and female engraved dies or type.

EMBOSSING DIES, STEEL: Complete set consists of one pair (male and female) with metal clearance allowed, to raise characters in relief above a stipulated surface.

EMBOSSING NUMBER HEAD, STEEL: Consists of a series of matched (male and female) Figure Wheels set up as a single unit to emboss numbers consecutively and automatically in light gauge free flowing material.

EMBOSSING TYPE: Letters or figures engraved single (in pairs – male and female) on rectangular steel blanks finished to a close tolerance for collective embossing.

ENGRAVE: The art of cutting designs and characters into hard materials suited for stamping.

EXTENDED CHARACTERS: Letters and figures cut wider than standard width. Regular extended characters have a width 70% of height of character. Extra extended characters – 85% of height. Double extended characters – 100% of height.

FACE OF CHARACTER: The stamping edge of engraved characters.

FACE OF STAMP: Striking end.


  • Flat Face: Characters made with a broad or heavy faced stamped letter.
  • Perforated Face: Characters made in a series of points to produce sharp pointed indentures into the material being marked.
  • Round Face: Characters made with half round face to produce round or oval indentures in the material being marked.
  • Sharp Face: Characters beveled to a narrow edge to produce sharp line indentures in the material being marked.
  • Extra Sharp Face: Fine edge face as above but the bevel is considerably reduced.

FLAT DIE HOLDER: A fixture for retaining a flat stamp for marking round pieces in a standard marking machine.

FLAT ROLL DIE: A flat die used in a marking machine to roll impressions on round tapered, or tubular parts.

FORCE: As used in the production of plastic mold dies. The portion of a mold that enters the cavity block and which exerts pressure on the molding compound. Is often designated as top force or bottom force, depending on the position it occupies in the mold assembly.

GOLD STAMPING DIE, STEEL: Stamp engraved with regular characters or designs, usually flat face, for use in a hot press for stamping colored or gold leaf into leather, plastic and composition. Cut extra deep, as a rule, approximately 100 bevels.

GOTHIC LETTERING: A sans serf typeface available in sharp face, flat face and open face characters.

GRADUATING DIE, STEEL: A marking die manufactured for the purpose of stamping graduations on a part.

HAND STAMP: Any hand-held stamp with which the force for impression is a hammer blow.

HEAT TREATING: The process of heating metals to increase hardness, durability, and useful properties. The steel used must have a certain proportion of alloying elements and are heated and cooled under controlled conditions.

HIGH PRODUCTION STAMP OR DIE: This term used for any stamp made from high carbon chrome steel. The steel type is not suitable for most hand stamps.

HIGH SPEED STAMP OR DIE: Any stamp made from high speed steel. High Speed Steel is often specified for stamping hot metals.

HOB: A Steel Punch or die with designs and/or characters engraved just as they will show on the finished product, usually furnished with a high polish and used for sinking die cast dies and molding cavities.

HOBBING: A process of forming die cast dies, mold cavities, or forces by forcing a hardened steel master , termed hob, of the same shape and dimensions as the molded or cast part desired into a soft steel cavity blank, which is subsequently trimmed to size, hardened and polished. A certain amount of metal is usually removed from time to time by machining it away between hobbing operations rather than by entire metal displacement as in hobbing. (See below)

HOLDER: (See “Interchangeable Type Holder, Flat Die Holder, Roll Die Holder, Roll Type Holder, Tool Post Holder, etc.”)

HOLDER: A tool to hold type, logotype, or stamps in alignment for marking.

HUB: Same type of die as Hobbing for sinking master dies. This term “hub” is used by jewelry manufacturers while the term “hob” is used by molding people.

HUBBING: The same general process as hobbing with the distinction that the entire metal removal is by displacement only. There is no matching and displacement as in hobbing.

IMPACT MARKING: A spring-loaded, snap action press is used to deliver a sharp, consistent marking force.

INCISE: To cut designs or writing into a surface. (See Stylus Marking)

INCLUDED ANGLE: The angle produced by the two side walls measured at the sharp face of the character. This angle usually is 90°.

INSERT: A marking tool made for the express purpose of being fitted or inserted into a die or fixture or another marking tool. May be interchangeable or replaceable with another insert.

INSPECTION STAMPS: Engraved with a symbol incorporating letters or figures inside or around the symbol for the purpose of designating the date, person, shift, etc.

INTAGLIO: Letters or figures or designs engraved sunk in a surface.


INTERCHANGEABLE TYPE HOLDER, HAND, PRESS OR MACHINE: Tool for retaining interchangeable type set up for collective marking in a straight line. Terminology as follows:

  • Interchangeable Radial Type Holder: uses a radial type for making a curved line.
  • Interchangeable Roll Type Holder: uses segment type for roll marking. Segment type is sometimes referred to as wedge type.

KNURL LOGOTYPE: A piece of steel cut from a ring and with the convex face engraved with more than one character.

KNURL TYPE HOLDER: A round tool which usually is keyed to a shaft and mounted in a carriage and has a machined recess around a portion of the periphery to accommodate knurl type.

KNURL TYPE: Piece of steel with side ground to an angle and engraved with single character. Several pieces of knurl type together present a convex face and can be used in roll marking.

KNURL: Round lettering tool used in roll marking flat parts and having characters engraved on periphery.

LASER MARKING; Laser light is used to mark character strings such as dates, serial numbers, manufacturing numbers, and models directly onto a product. The advantages of laser marking include permanence, flexibility, and reduced running costs. Laser marking makes it possible to mark clearly on different shapes, even those with curved or contoured surfaces.

LETTERS AND FIGURES, STEEL: Single character hand stamps for stamping on various materials one letter at a time by hammer blow.

LOG HAMMER OR LOG STAMPS: Letters, figures, or designs cut on the end of an eye forging with handle inserted in the eye enabling the stamp to be used as a hammer for indenting data into logs or stacked lumber with a single hammer action blow.

LOGOTYPE: Multi-character type, i.e. stamps made type high (0.918 printer’s type standard or 1.000″ marking tool manufacturer’s standard) cut with more than one character per piece.

LOW STRESS CHARACTER: A round face or dot designed character.

MACHINE STAMP: This term is used for any marking tool other than a press stamp or roll die that will be used in a machine or die holder. Such a stamp may contain tapped or counter sunk holes or dove tail shank or tapered sides or ends, etc.

MARK PARALLEL TO AXIS: Round parts marked lengthwise on O.D. with lettering running parallel to axis.

MARKED AROUND PERIPHERY: Round parts marked on O.D. at 90° to axis of the part.

MARKING MACHINE: Any machine designed to produce, by mechanical means, impact or motion, an impressed marking in parts or materials placed in the machine.

MARKING TOOL: Collective term for steel stamps, embossing dies, letters and figures, etc. Correct terminology as follows:

  • Branding Die
  • Coining Die
  • Debossing Die
  • Embossing Die
  • Embossing Head
  • Flat Die Holder
  • Gold Stamping Die
  • Hand Stamp
  • Hob
  • Hub
  • Insert
  • Inspection Stamp
  • Interchangeable Steel Type Holder
  • Log Hammer
  • Logotype
  • Machine Stamp
  • Mold Stamp
  • Numbering Head
  • Press Stamp
  • Radial Type
  • Roll Die
  • Roll Die Holder
  • Segment Type
  • Semi-Coining Die
  • Spring Return Holder
  • Steel Letters & Figures
  • Straight Type
  • Symbol Stamps

MICRO-PRECISION MARKING: A non-stressing technique for cold marking on materials produced by computer-controlled synchronization of a high-frequency vibrating stylus and X-Y movement system. Permanent information is marked one indentation-at-a-time by the stylus. Also, know as dot peening pin stamping and programmable stamping.

MOLD CAVITY: The part of a mold into which molding compound is deposited and in which it is formed. (Sometimes termed Impression)

MOLD STAMPS: Single letters and figures for stamping glass, rubber, or plastic molds. Usually reverse flat face characters without much bevel. For multi-character mold stamps. (See “Hobs” and “Reverse Characters”)

MORTISE: A recess machined into a holder or die to accept a die insert.

NUMBERING HEAD, STEEL: Numbering device for stamping figures consecutively into metal and other materials. Usually automatic, the heads are inset with a series of rotating wheels, each of which carry the stamping figures 0 through 9, or letters, if required. Used by hand, press or marking machine.

PERCUSSION MARKING: (See Stylus Marking)

PINSTAMP®: A dot peening term trademarked by Telesis Technologies, Inc.

PRESS STAMP: For use in punch, kick, spring, hydraulic, pneumatic or arbor press. Usually has a round shank of designated length and diameter. Body may be round, square, or rectangular, as required to suit lettering.

SQUARE ◙ DOT®: Columbia Marking Tools’ Patented UID-2D data matrix marking technology commonly known as SQUARE ◙ DOT® produces highly readable & longest lasting 2D/UID Direct Part Marking codes.

RAISED CHARACTER ENGRAVING: Background material is removed with a cutter to leave a raised character on the steel block.

REGULAR CHARACTERS: Letters and figures reading from right to left on the face of the stamps are termed regular. They indent an impression reading regular, i.e. from left to right.

REVERSE CHARACTERS: Letters and figures reading from left to right on the face of the stamp or termed reverse. They indent and impression reading reverse, i.e. from right to left as would be required on die or molds, which in turn, produce an impression that must be correctly read in its final stage.

ROCKWELL: Term for a material hardness, normally Rockwell C.

ROLL DIE HOLDER/CARRIAGE: Holding fixture for retaining the roll die in a marking machine.

ROLL LEAF DIE: A die engraved with flat face regular characters or designs heated to transfer colored foil into the surface of plastics, leather, paper, etc. (usually dep engraved with approximately 10-degree of bevel)

ROLL DIE, STEEL: Circular die with the marking data engraved on the periphery of the roll. Imprinting is produced by a rolling-in operation similar to knurling. (obsolete term: Knurl Die)

SCRIBE MARKING: Scribe marking uses a pneumatically driven pin which is driven into the metal surface to be marked. It is then moved through the metal, engraving the required inscription. It therefore gives a continuous engraved line. is produced by a rolling-in operation similar to knurling

SEGMENT (WEDGE) TYPE: Single characters engraved on the large end of blanks tapered to fit a mortised roller die.

SEMI-COINING DIES: (for Embossing or Debossing) Complete set consists of one pair (male and female) with little or metal clearance allowed. For the purpose of raising or sinking letters, figures, or designs above or below a stipulated in heavy material.

SHOULDER: This term is used when the surface or land at the base of the lettering is left remaining to the extreme limit of the die blank with no second bevel ground to the lettering.

SPRING RETURN HOLDER: Fixture for retaining a roll die when the periphery of a part is being marked in a screw machine or turret lathe.

STAMP RELIEF: How much the featured image will protrude above the surface of the stamp face.

STANDARD CHARACTERS: A standard character is a letter or figure engraved so that the width is 60% of the height of the character. (See “Condensed” or “Extended” for other ratios)

STRAIGHT LOGOTYPE: Piece of steel with straight sides engraved with more than one character and used in straight type holder for roll-marking round parts.

STRAIGHT TYPEHOLDER: Tool which has a machined slot or recesses to accommodate straight type.

STRAIGHT TYPE: Piece of steel with straight sides engraved with a single character.

STYLES: (See “Faces of Characters”)

STYLUS MARKING: A sharp, pointed instrument used for writing, marking or engraving. Marking is accomplished via a series of impressions (made by a pneumatically driven, computer-controlled mechanism) similar to dot matrix printing.

SUNK CHARACTER ENGRAVING: Sunk characters are used on mold work and on engraving piece parts where characters are to be color filled.

SURFACE AREA OF STAMP FACE: Refers to the total length and thickness of a character, text or design. In other words, the total amount of black (filled) areas comprising the character(s), logo or design.

SYMBOL STAMPS: Marking tools for impressing a single emblem or design in accordance with a symbol chart standardized by the manufacturer. Symbols carrying letters or figures grouped inside or around the symbol are termed Inspection Stamps.

TEMPLATE: A relatively thin metal plate cut in the shape of the contour or outline of the surface to be machined or engraved.

TIER STYLE: Letters or figures appear one above the other so as to read vertically.

TOOL POST HOLDER: A fixture for retaining roll die when the periphery of a part is being marked in an engine lathe.

 TOOL STEELS: Six groups of steels; water hardened, shock steel, cold worked, hot worked, high-speed and special purpose tool steels. Each tool steel has various chemical characteristics for specific applications.

TRUNCATED TYPE: Type tapered outward on the sides from the face of the blank to the base (opposite of segment type) for use in concave holders.

TYPE, RADIAL STYLE: Letters or figures engraved singly on steel blanks with tapered sides for collective imprinting in a curved line.

TYPE, SEGMENT STYLE: Letters or figures engraved single on steel blanks tapered on the sides from face to base for collective imprinting in a roll type holder on convex or concave type holder. NOTE: Multi-character type are termed Logotype.

TYPE, STRAIGHT STYLE: Letters or figures engraved singly on rectangular steel blanks dimensioned to close tolerances for collective imprinting in one or more straight lines.

TYPEFACE: The surface of a body of type that makes the impression, including the size, or style of the letter or character on the type.

TYPEHOLDER: A fixture that holds individual type used to compose alpha/numeric characters into desired text. Typeholders can be hand held or mounted in a press. (See Straight Type Holder)

TYPING: This term is used when small amounts of metal are to be displaced in small groups or sections of a die or cavity. Types are similar to what in the marking tool and die industry are referred to as counters with the exception that the typing operation is usually completed entirely by metal displacement, while in countering displacement of the metal is but a first operation to be followed by further material removal.

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