The title block is the boxed table in the lower right corner of an engineering drawing that identifies it: the drawing number, title, revision, sheet size, scale, sheet number and the CAGE code of the company that owns the design, with who drew, checked and approved it. Beside it sit the default tolerances for every dimension that has none of its own, the material and finish, and the assembly the part goes into.
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Where it is
In the lower right corner of the drawing area, on ASME and ISO sheets alike, so the drawing's identity is in the same place on every sheet.
On an ASME Y14.1 sheet the title block fills the lower right corner, inside the border. Beside it, usually to its left, sit the blocks that go with it: the application block (next assembly and used on), and the default tolerances, material and finish, which many companies print as part of the title block itself. The revision block usually sits in the upper right corner.
On an ISO sheet the title block sits in the bottom right corner of the drawing frame (ISO 5457), no more than 180 mm wide (ISO 7200), and carries the same information under different names ("ISO 7200 title blocks" below).
On a drawing of several sheets, sheet 1 carries the full title block. Later sheets often carry a shorter continuation title block that repeats the drawing number, the sheet size and the sheet number, so every sheet can be identified on its own.
Where the sheet's zones, borders and sizes come from is on drawing sheet sizes, which also names the size of any print or scan from its measurements.
Box by box
A typical ASME-style title block, then each box with the captions it is printed under. Companies arrange the boxes their own way, so read the captions, not the positions.
Printed as DWG NO DRAWING NUMBER
The drawing's identity: the number every parts list, purchase order and change order uses to refer to it. The company that owns the design assigns it, and it is not reused for another drawing. Together with the CAGE code it identifies the drawing uniquely, since two companies can both have a drawing 10045 (ASME Y14.100).
Printed as PART NO P/N PIN
The number the part itself is ordered, stocked and marked by. On many drawings it is simply the drawing number, and the title block has no box for it. A drawing that defines several variants gives each a dash number, so the parts are the drawing number with a suffix, such as SG-2001-1 and SG-2001-2. ASME Y14.100 calls it the part or identifying number, PIN.
Printed as TITLE
The item's name: a basic name, which is a noun or a noun phrase, then any modifiers, each after a comma, as in BRACKET, MOUNTING. A noun phrase that is the item's own name stays whole: JUNCTION BOX, not BOX, JUNCTION. Titles avoid abbreviations where they can, and stay the same on every sheet (ASME Y14.100).
Printed as REV
The drawing's current revision. Under ASME Y14.35 revisions are capital letters in sequence from A, skipping I, O, Q, S, X and Z; the first release may show a dash instead of a letter. Some companies number their revisions instead. The letter here should match the latest entry in the revision block, which lists what each revision changed: revision history blocks, explained.
Printed as SHEET 1 OF 2 SH
Which sheet this is, and how many the drawing has. Every sheet carries the same drawing number, and the drawing is complete only with all of them, so a print marked SHEET 1 OF 2 is half a drawing.
Printed as SCALE NTS
The ratio of the drawing's size to the part's: 1:1 is full size, 1:2 half size, 2:1 twice size. NONE or NTS (not to scale) means the views are not drawn to a scale, and a view drawn at another scale says so beneath it. The dimensions govern, not the print, which is why many title blocks add DO NOT SCALE DRAWING.
Printed as SIZE DWG SIZE
The sheet size the drawing was made on: a letter from A to F on an ASME Y14.1 sheet (A is 8.5 × 11 in, D is 22 × 34 in), or A0 to A4 on an ISO sheet. It tells you whether a print is full size: a D-size drawing printed on B-size paper is at half its scale. Drawing sheet sizes lists them all.
Printed as CAGE CODE CODE IDENT NO FSCM NO
A five-character code for the company or government activity that owns the design. CAGE stands for Commercial and Government Entity; the US Defense Logistics Agency assigns the codes, and outside the US the NATO equivalent is the NCAGE code. Older drawings call it the code identification number or FSCM, the Federal Supply Code for Manufacturers.
Printed as MATERIAL MATL
What the part is made of, usually with the specification that defines it, such as ASTM A36 for a structural steel. The box may instead point elsewhere, SEE NOTE 3, and on an assembly drawing it is often blank, because each part's material is in the parts list.
Printed as FINISH TREATMENT
The coating or treatment the part receives, with its specification: ANODIZE PER MIL-A-8625, TYPE II, CLASS 1 (now MIL-PRF-8625), or PASSIVATE PER ASTM A967. Surface roughness is a different thing, a number such as 125 or 3.2 given on the surfaces or in a note; the surface finish converter translates between its units. Heat treatment, when it is not in a note, has a box of its own.
Printed as UNLESS OTHERWISE SPECIFIED TOLERANCES
The defaults for every dimension that has no tolerance of its own. On an inch drawing they usually go by the number of decimal places, so a dimension written 1.50 takes the .XX tolerance and 1.500 the .XXX one, with separate values for fractions and angles. The block usually states the units too, and the standard the drawing is read by, such as ASME Y14.5.
The values are the company's choice, not set by ASME Y14.5, so read them off each drawing. ISO drawings usually cite a general tolerance class instead, such as ISO 2768-m (medium) from ISO 2768-1.
Printed as DRAWN CHECKED ENGR APPROVED
Who drew the drawing, who checked it and who approved it for release, each with a date; companies add boxes for engineering, quality or manufacturing as they need. These dates belong to the drawing's original release: each later revision is dated and approved in the revision block.
Printed as NEXT ASSY USED ON
The application block. NEXT ASSY names the assembly the part goes into directly; USED ON names the end product or model it serves. It shows where a change to this part will be felt. Because it goes out of date whenever the part is used somewhere new, where a part is used is often tracked in a PLM or ERP system instead.
Printed as WEIGHT CONTRACT NO THIRD ANGLE PROJECTION
Weight, calculated or actual. Contract number, on drawings made under a contract. The projection symbol, a truncated cone drawn in two views, saying how the views are arranged: third-angle projection is the US convention (ASME Y14.3), and first-angle is common elsewhere (ISO 5456-2 defines both). And proprietary or distribution notices, which say who may see or copy the drawing.
The title block speaks for the whole drawing. Callouts on the views are read where they sit: a thread such as 1/4-20 UNC-2A with the thread callout decoder, a feature control frame with the GD&T symbols.
Sources: ASME Y14.1 (sheet format), ASME Y14.100 (drawing numbers, part numbers and titles), ASME Y14.35 (revisions), ASME Y14.5 (dimensioning and tolerancing), ASME Y14.3 and ISO 5456-2 (projection), ISO 2768-1 (general tolerances). The CAGE code is the Defense Logistics Agency's.
Abbreviations
ASME Y14.38 lists the standard abbreviations for drawings, but a title block's captions are often the company's own, so the same box can read CHK, CHKD or CHECKED.
| Printed as | Means |
|---|---|
| DWG NO | Drawing number |
| REV | Revision |
| SH, SHT | Sheet, as in SHEET 2 OF 3 |
| SIZE | The sheet size letter: A to F, or A0 to A4 |
| NTS | Not to scale |
| CAGE, CODE IDENT, FSCM | The design owner's five-character code |
| P/N, PN, PIN | Part number; PIN is part or identifying number |
| MATL | Material |
| FNSH | Finish |
| HTTR | Heat treat |
| UOS | Unless otherwise specified |
| TOL | Tolerance |
| DWN, DR | Drawn by |
| CHK, CHKD | Checked by |
| ENGR | Engineer: the engineering approval |
| APVD, APPD | Approved by |
| QA | Quality assurance |
| MFG | Manufacturing |
| NEXT ASSY, NA, NHA | Next assembly; next higher assembly |
| WT | Weight |
Sources: ASME Y14.38 (abbreviations) for DWG, REV, SH, NTS, FSCM, PN, MATL, FNSH, HTTR, UOS, TOL, DWN, ENGR, APVD, QA, MFG, NA, NHA and WT; ASME Y14.100 for PIN. The others are forms title blocks commonly print. The rest of a drawing's abbreviations are in the drawing abbreviations glossary.
ISO drawings
An ISO title block carries the same information under different names, in a block no more than 180 mm wide.
ISO 7200 names its fields for what they are, rather than by caption:
The material, the general tolerance class (ISO 2768-1) and the projection symbol sit beside these, much as they do on an ASME sheet.
Sources: ISO 7200 (title block data fields), ISO 5457 (sheet layout), ISO 2768-1 (general tolerances).
Questions
In the lower right corner of the drawing area, on ASME Y14.1 and ISO 5457 sheets alike. On an ASME sheet the revision block usually sits in the upper right corner, and the application block (next assembly and used on) to the left of the title block. Sheets after the first often carry a shorter continuation title block that repeats the drawing number.
It identifies the company or government activity that owns the design. CAGE stands for Commercial and Government Entity: a five-character code assigned by the US Defense Logistics Agency. Older drawings label the box CODE IDENT or FSCM (Federal Supply Code for Manufacturers). Together with the drawing number, it identifies a drawing uniquely.
Often, but not always. Many drawings use the drawing number as the part number. A drawing that defines several variants gives each a dash number, so its part numbers are the drawing number with a suffix such as -1 or -2. And the parts on an assembly drawing are mostly defined on drawings of their own.
It introduces the defaults: the units, tolerances and other conditions that apply to every dimension and feature the drawing does not give its own. A tolerance written on a dimension, or a note that says otherwise, takes precedence. The default values are each company's choice, not set by ASME Y14.5, so read them off every drawing.
The ratio of the drawing's size to the part's: 1:1 is full size, 1:2 is half size and 2:1 is twice size. NONE or NTS (not to scale) means the views are not drawn to a scale. The dimensions govern, not the print, which is why many title blocks say DO NOT SCALE DRAWING.
The REV box in the title block states the drawing's current revision. The revision block lists every revision: its letter, what changed, the date and who approved it. The REV box should match the latest entry in the revision block.
From SpecCapture
SpecCapture reads the title block, the revision history, the bill of materials, the hole table, the application block, the tabulated dash numbers and the general notes off 2D engineering drawings, with a box on the drawing around every value it reads, so checking it takes a glance.
From the title block: part number; drawing number; revision; title; material; stock size; finish or coating, and plating specification; surface roughness; heat treatment; scale; units; sheet size; sheet number and sheet count; who drew, checked and approved it, with the dates; weight; general tolerances for fractions, decimals (by number of places) and angles; projection angle; drawing standard; CAGE code; and export-control marking.