Engineering drawing abbreviations and symbols are used to communicate and detail the characteristics of an engineering drawing. This list includes abbreviations common to the vocabulary of people who work with engineering drawings in the manufacture and inspection of parts and assemblies.
Technical standards exist to provide glossaries of abbreviations, acronyms, and symbols that may be found on engineering drawings. Many corporations have such standards, which define some terms and symbols specific to them; on the national and international level, ASME standard Y14.38. and ISO 128 are two of the standards. The ISO standard is also approved without modifications as European Standard EN ISO 123, which in turn is valid in many national standards. Australia utilises the Technical Drawing standards AS1100.101 (General Principals), AS1100-201 (Mechanical Engineering Drawing) and AS1100-301 (Structural Engineering Drawing).
Abbreviation or symbol Definition Description 0-9 A across corners Commonly used when measuring the corners of a hex drive, such as a hex nut. across flats Commonly used when measuring the flat surfaces of a hex drive, such as a hex nut.AFFabove finished floorA dimension that establishes a distance away from the finished floor. Example would be the top of a coffee table to the shag of the carpet, not where the bottom of the tables feet dig in. American Iron and Steel Institute The AISI acronym is commonly seen as a prefix to steel grades, for example, "AISI 4140". The SAE steel grade system was formerly a joint AISI-SAE system. or aluminium alloy American Referring to the United States Aerospace Material Standards Standards in materials science and engineering maintained by SAE International and widely used in the aerospace manufacturing industries. Army-Navy A prefix for standard hardware (catalog hardware) ID numbers. Came from the era of circa 1890s-1945, when the U.S. Army and Navy were leading the way on product standardization for logistics improvement, yielding the United States Military Standards system. Today industry and ISO also do a lot of this standardization specification, freeing the U.S. DOD and military to do less of it (as explained at United States Military Standard > Origins and evolution), although many MIL standards are still current. (See also MS- and NAS.) anneal, annealed American National Standards Institute And the many standards that it issues, for example, ANSI Z87.1. . approximately acceptable quality level The threshold of defectiveness that is allowable in a group of parts. It is trivial to say that no one wants any error, and that everyone wants uniform perfection; but in the real world, it almost never happens. The intelligence behind defining AQLs is in figuring out how much error is tolerable given the costs that would be incurred by any efforts to further reduce its incidence. as required An abbreviation used in parts lists (PLs, LMs, BoMs) in the quantity-per-assembly field when a discrete count is not applicable. For example, in an assembly with a bolted joint using four bolts, the PL quantity column will say "4" for the bolt PN, "4" for the nut PN, and "AR" for the liquid threadlocker that will be applied. Aerospace Standards; Australian Standards 1. Aerospace Standards, technical standards maintained by SAE International and widely used in the aerospace manufacturing industries. Standard aerospace hardware sometimes has the AS- prefix in the catalog numbers. 2. Australian Standards, standards per Australian industry. AS, APS, APV, AV, APSL, AVL approved product supplier, approved vendor, approved-product-supplier list, approved-vendor list When only certain companies are approved by the CDA to manufacture the product (that is, to make what the drawing depicts/defines), they are called by names such as "approved supplier", "approved product supplier", "approved vendor", or "approved product vendor". The list of such companies (which usually changes over time) is called an APSL, AVL, or similar names. Vetting the companies on this list requires the CDA to audit (and possibly periodically re-audit) the companies, which incurs an overhead expense for the CDA. Therefore, smaller companies will often cite larger companies' lists in order to avoid the cost of duplicating the effort. American Standards Association Former name for ANSI (1920s-1960s). American Society of Mechanical Engineers And the many standards that it issues, for example, ASME Y14.5. assembly referring to an assembly of parts rather than just one (sub)part ("piece part", "detail part"). Formerly the American Society for Testing and Materials; now ASTM International Maintains technical standards, especially regarding materials science and engineering and metrology. average American Wire Gauge B basic dimension A basic dimension is one that is the theoretical value without any tolerance range. It does not serve as an acceptance criterion. It is thus similar in some respects to a reference dimension. The reason why a basic dimension does not carry a tolerance is that its actual value will fall (acceptably) wherever it is put by other features' actual values, where the latter features are the ones with tolerances defined. A common and simple example is hole location: If a hole's centerpoint location has a position tolerance, then the centerpoint's coordinates do not need (and should not have) separate tolerances applied to them. Thus they are instead given as basic dimensions. In modern practice basic dimensions have a rectangular box around them, or sometimes the word "BASIC". bolt circle bolt circle diameter BHCbolt hole circleSame definition as the bolt circle diameter button head cap screw Like an SHCS but with a button head. Brinell hardness number or BOM bill of materials Also called a list of materials (LM or L/M). Overlaps a lot in concept with a parts list (PL or P/L). There is no consistently enforced distinction between an L/M, a BoM, or a P/L. BoP or BOPbought out partA part which is outsourced from an external supplier, or "bought out". , B/P blueprint "per B/P" = "per drawing" bronze basic dimension See basic dimension info above. C computer-aided design, computer-aided drafting; cadmium [plating] Commercial and Government Entity [code] A CAGE code is a unique identifier to label an entity (that is, a specific government agency or corporation at a specific site) that is a CDA, ODA, or MFR of the part defined by the drawing. One corporation can have many CAGE codes, as can one government, because each division, department, and site (campus) can have its own CAGE code. The same CAGE code can change owners over the years. For example, a CAGE code that formerly referred to a certain Martin Marietta site will now refer to Lockheed Martin at that same site (although the buildings may have been replaced and the signage may say different names). centre-to-centre; on centres Defines centre-to-centre distance of two features, such as two holes. cubic boron nitride A material from which some cutter inserts are made. current design activity The CDA is the entity (whether it be a corporation, a unit of a national military or ministry of defence, or another civilian government agency) that currently has design authority over the part design (definition). It may be the entity who first designed the part (that is, the ODA), but today it is also likely to be a designated successor entity, owing to mergers and acquisitions (M&A) activity (e.g., ODA company was bought by CDA company); contract letting (e.g., an Army engineering department ODA turns over the design activity to the prime contractor that makes most or all of the parts, turning that contractor into the new CDA); privatization (e.g., a government privatizes the design and manufacture of materiel, and a state arsenal [state armory] ODA transfers design authority to a private armory [defense contractor] ODA); or patent licensing (e.g., a patent-holding inventor [ODA] licenses one or several companies to manufacture products using his intellectual property, in which case the "same" part could end up with multiple design authorities, although they may not be considered the official/nominal CDA). CERT or cert certification For example, certification of metallurgical content and processes CG centerless ground, centerless grinding Center mark Defines the center of a circle or partial circle. chamfer cast iron No longer a commonly used abbreviation. Better to spell out for clarity. or ℄ centreline or centerline; class 1. Center line, the central axis of a feature. 2. Class, for example, "paint per spec XYZ revision C type 1 class 2" may be abbreviated as "paint per spec XYZ REV C TY 1 CL 2" or even in some cases "paint per spec XYZ-C-1-2". (The latter practice is not uncommon but is cryptic for workers with minimal training and experience. The first two options are better practice.) cement mortar lined, cement mortar coated, or cement mortar lined & coated Commonly used together with "WSP" ("welded steel pipe") computer numerical control controlled radius Radius of an arc or circle, with no flats or reversals. This strict version of radius definition is specified in demanding applications when the form of the radius must be controlled more strictly than "just falling within the dimensional tolerance zone". It is poor engineering to specify a CR instead of an R simply on the theory of enforcing good workmanship. CR is for critical features whose performance truly requires near-perfect geometry. Like most such characteristics, its presence increases the price of the part, because it raises the costs of manufacturing and quality assurance. corrosion-resistant [steel] Largely synonymous with stainless steel, unless specific grades, specs, and distinctions are made on the drawing. Some people treat CRES as a subset of the stainless steels. cold rolled steel; on centres Defines centre-to-centre distance of two features, such as two holes. C/TCorrelation / Tracking or counterbore or countersink carton D depth, deep, down Defines the depth of a feature. diameter Diameter of a circle. In a feature control frame (FCF), the ⌀ symbol tells you that the tolerance zone for the geometric tolerance is cylindrical. Abbreviations for "diameter" include ⌀, DIA, and D. diameter; delta Abbreviations for "diameter" include ⌀, DIA, and D. For delta usage, see for example "delta notes". diameter Diameter of a circle. Abbreviations for "diameter" include ⌀, DIA, and D. ductile iron pipe dimension, dimensioning , do ditto Seen occasionally in older drawings instead of repeating a given dimension. , DoD [U.S.] Department of Defense See also MOD. digital product definition A synonym of MBD. drawing (Australian Standard AS1100.101 pg.8 Table-1.1) E EDedge distanceDrilled holes, and fasteners are commonly required to have a minimum edge distance (min ED). , ECO, ECN engineering order An order from the engineering department (to be followed by the production department or vendor) overriding/superseding a detail on the drawing, which gets superseded with revised information. Also called by various other names, such as engineering change order (ECO), engineering change notice (ECN), drawing change notice (DCN), and so on. See also REV. , ,EQS equal, equally, equally spaced For example, "⌀10 4X EQL SPACED ON BC" means "drill four holes of 10mm diameter equally spaced around the bolt circle."