# Engineering Drawing Line Types Reference (ASME Y14.2 Style) > Source: https://netray.co/tools/engineering-drawing-line-types-reference > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: Free Tools ## Short answer Lookup table of common drawing line types, their weight, pattern and what each is used for on a part or assembly drawing. ## Category engineering-plm ## Audience - Design engineer - Engineering manager - Quality engineer ## Tool **Kind:** worksheet **Mode:** reference **Columns:** #### Line type **Key:** line **Type:** text #### Weight **Key:** weight **Type:** text #### Pattern **Key:** pattern **Type:** text #### Typical use **Key:** use **Type:** text **Rows:** **Line:** Visible (object) line **Weight:** Thick **Pattern:** Continuous **Use:** Edges and contours of the part that can be seen in the view **Line:** Hidden line **Weight:** Medium or thin **Pattern:** Short evenly spaced dashes **Use:** Edges and features behind a surface, only where they clarify the view **Line:** Center line **Weight:** Thin **Pattern:** Long, short, long dash sequence **Use:** Axes of holes, cylinders and symmetrical features, and bolt circles **Line:** Dimension line **Weight:** Thin **Pattern:** Continuous with arrowheads or ticks **Use:** Shows the extent of a dimension between extension lines **Line:** Extension line **Weight:** Thin **Pattern:** Continuous, small gap at the object **Use:** Extends feature edges so a dimension can be placed outside the view **Line:** Leader line **Weight:** Thin **Pattern:** Continuous with arrowhead **Use:** Points from a note, callout or symbol to the feature it describes **Line:** Cutting-plane line **Weight:** Thick **Pattern:** Long dash with two short dashes, or evenly spaced dashes **Use:** Shows where a section view is taken, with arrows for viewing direction **Line:** Section line (cross-hatching) **Weight:** Thin **Pattern:** Continuous parallel lines, usually at 45 degrees **Use:** Fills the cut surface in a section view, symbols can show material **Line:** Short break line **Weight:** Thick **Pattern:** Freehand wavy line **Use:** Shows a short break in a long part to save drawing space **Line:** Long break line **Weight:** Thin **Pattern:** Ruled line with freehand zigzags **Use:** Shows a long break on parts of constant cross section **Line:** Phantom line **Weight:** Thin **Pattern:** Long dash with two short dashes, repeated **Use:** Alternate positions of moving parts, adjacent parts and repeated detail **Line:** Stitch line **Weight:** Thin **Pattern:** Evenly spaced small dashes **Use:** Indicates a sewing or stitching path, and sometimes a hidden feature **Line:** Chain line **Weight:** Thick **Pattern:** Long, short, long dash sequence **Use:** Indicates a surface or area that has a special requirement such as a treatment zone **Line:** Symmetry line **Weight:** Thin **Pattern:** Center line with two short parallel lines at each end **Use:** Shows a view is shown as half of a symmetrical part **Notes:** Line weights and patterns are summarised from common drafting practice such as ASME Y14.2. Absolute widths depend on your drawing standard and plotting setup. Check your company standard and the standard cited in the contract. ## Content **Intro:** Reading a drawing correctly starts with knowing what each line means. This quick reference lists the common line types, their weight and pattern, and how they are used. It is useful for new engineers, for supplier onboarding and for standardising drawing templates across a team. **Sections:** #### How to use the table **Body:** Search for a line name such as phantom or cutting to jump to its row, or search for a use such as symmetry or section. Export the table to Excel or PDF and attach it to a drafting standard, a CAD training pack or a supplier drawing requirements package. The weight column helps you check that a template has distinct thick and thin line settings. **Bullets:** - Use thick lines for visible edges, cutting planes and short breaks - Use thin lines for dimensions, extension lines, leaders and hatching - Add hidden lines only where they improve clarity #### Where the conventions come from **Body:** Line conventions in US practice are set mainly by ASME Y14.2, with ISO 128 covering the same ground for metric drawings. Both define a small family of line types so that any trained reader interprets a drawing the same way. A common rule of thumb is that a thick line is about twice the width of a thin line. The aim is legibility after reduction, scanning and faxing or low resolution printing, so keep the weight contrast clear. #### Common mistakes **Body:** Frequent problems include center lines drawn as plain dashes, hidden lines that clutter a view and make features ambiguous, cutting plane lines without direction arrows, and hatching that crosses a dimension without a break for the text. Another common issue is CAD layers where the line weight is set to the same value for everything, which makes the drawing look flat and hard to read after plotting. Review a sample print, not only the screen. **Cta:** If you manage drawing standards across several plants and want routine release checks tied to your PLM and ERP data, Netray can talk through options. **Faq:** #### What is the difference between a phantom line and a center line? **Answer:** A center line marks an axis or symmetry and uses a long, short, long pattern. A phantom line uses a long dash followed by two short dashes and shows alternate positions, adjacent parts or repeated detail. They look similar, so check the pattern carefully. #### How thick should thick and thin lines be? **Answer:** Standards give minimum widths and a ratio, commonly thick being about twice thin. Typical values are around 0.6 mm for thick and 0.3 mm for thin, but your company standard or CAD template sets the exact values. Confirm with a test plot. #### Should hidden lines always be shown? **Answer:** No. Practice is to show them only where they make the drawing clearer. Too many hidden lines make a view hard to read, so a section view or an additional view is often a better choice. #### Does ISO use the same line types? **Answer:** ISO 128 defines a similar set with different naming and a defined set of line widths. Most basic types are equivalent, but codes, widths and terminology differ, so follow the standard your drawing cites. ## Search terms engineering drawing line types, ASME Y14.2 line conventions, visible line hidden line center line, phantom line meaning, cutting plane line, drawing line weights thick thin, section line 45 degrees, types of lines in technical drawing --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json