Technical Drawing Standards

Technical Drawing Standards: Lettering Heights

May 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: AnnotationsThe BS Standards defines a range of eight Nominal heights for lettering.

The sizes are:

1.8, 2.5, 3.5, 5.0,7.0,10,14 and 20mm

A formula of 1:2 ( 1:1.4) is used to calculate the sizes available,the same formula that calculates paper sizes and line weights.

The recommended Minimum sizes are:

Paper sizeNotes & DimsTitlesHeadings

A03.557

A12.53.55

A22.53.55

A32.53.55

A41.82.53.5

BS EN ISO 3098-0:1998 Technical product documentation. Lettering. General requirements.The BS Standards defines a range of eight Nominal heights for lettering in Technical drawings

Technical Drawing Standards: Dimension StylesApril 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: Annotations

The BS ISO Technical drawing Standard describes Five different dimension styles for us to choose from. The first two, Closed Filled and Closed Blank, would usually be used in Engineering. Oblique is often favoured by Architects. Ive never seen anyone use Open 90 or Open 30, except when sketching by hand. There are []

Technical Drawing Standards: Leader Lines.February 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: Annotations

A leader line is a line that establishes a connection between a graphical representation of an item and some text. A leader points to a bit of our drawing and says: Oi Look Here and Read This!. The leader line itself should be a continuous Thin line (see this post on Linetype Definitions). A []

The BS ISO Technical drawing Standard describes Five different dimension styles for us to choose from.

The first two, Closed Filled and Closed Blank, would usually be used in Engineering. Oblique is often favoured by Architects. Ive never seen anyone use Open 90 or Open 30, except when sketching by hand.

There are a couple of Alternative terminators that have special meanings. A circle is indicative of an origin point. In the example of running dimensions below, all the dimension values spring from the same datum point.

The Point terminator is used for when the dimensions are too close together to allow room for an arrowhead. An Oblique stroke can be used instead.

Technical Drawing Standards: Leader Lines.

February 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: AnnotationsA leader line is a line that establishes a connection between a graphical representation of an item and some text. A leader points to a bit of our drawing and says:Oi Look Here and Read This!.

The leader line itself should be a continuous Thin line (see this post on Linetype Definitions). A leader line also has a terminator and some text. A leader line may have a reference line under the text.

The British technical drawing standards give us four different types of terminators to use with our leader lines.

An arrow terminator is used to point to an edge of an item. The dot is used to point to a face. The Architectural tick can be used for referring to multiple parallel edges. The final type of line has no terminator, and is used for pointing at dimension lines or lines of Symmetry.

Leader lines can have multiple segments and you can use one annotation to reference multiple faces and edges.

You can reference multiple parallel edges or faces with one leader.

It is recommended that you draw your leader lines at an angle to the rest of the drawing i.e. Not parallel to the drawing itself. Increments of 15 are advised.

Finally, your Instruction text can be centred to the reference line, or it can sit above the reference line. The text should be a least twice the line thickness above the reference line. The text should never touch the reference line itself.

An Icon to represent the ISO Standard Line types

October 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: Line Type DefinitionsI tend to Post about whatever I am passionate about,

Today I was Inspired to draw this Icon representation of the ISO Line types

I Like it!

[EDIT]I just worked out where I got that idea from 8-~

AutoCAD Line Type Scales, The Secret Truth.

May 2010 | Paul Munford Filed Under: AutoCAD Tutorials Tagged With: AutoCAD Productivity, Line Type DefinitionsThe best thing about AutoCAD is that the programmers never throw anything away. The worst thing about AutoCAD is that the programmers never throw anything away!

There are now four AutoCAD variables that govern your line type scale. It can seem a little confusing, so hang on tight while we take a run through them

Suggested values:

LTSCALE = 1.0

CELTSCALE = 1.0

PSLTSCALE = 1

MSLTSCALE = 1

To change a variables value, simply type it in at the command line and enter a new value when prompted. These values are saved in the drawing, so its worth getting them right in your template file.Why should I use these values?

Why have I suggested these settings? Let me run through each one in a little more detail.

LTSCALE

This variable sets the Line Type Scalefactor globally.

Use LTSCALE to change the scale factor of all linetypes for all geometry in a drawing. Changing the linetype scale factor causes a REGEN so you can see the result of your changes straight away.

If you only draw and plot from Model space, you can use LTSCALE to scale all your line types to suit your plot scale. If you use Paper space layouts, just leave this set at 1.0.

CELTSCALE

Sets the Current Entity Line Type Scale i.e. whatever you are about to draw next!

The CELTSCALE is relative to LTSCALE. By setting CELTSCALE to 0.5 the next line you draw will have a linetype scale factor which is half that of the lines drawn previously.

You can use this feature to vary the linetype scale of your lines as you draw them. You can also change the line type scale of some geometry after youve drawn it by selecting the geometry and looking for LTSCALE in the properties palette.

Dont forget to set the CELTSCALE back to match LTSCALE when youre finished.

PSLTSCALE

This variable controls the linetype scaling of geometry displayed in paper space viewports Paper Space Line Type Scale.

This variable only has two settings. Setting PSLTSCALE to 0 (Off) will mean that the linetype scale factor of your modelspace geometry will not be effected by the scale of your viewport.

Setting PSLTSCALE to 1 (On) means that the line type scale of your modelspace geometry will be scaled to match the viewport scale.

If you use paper space layouts, turning paper space line type scaling on ensures that all your geometry will have the correct line type scale, no mater what the viewport scale is.LTSCALE and CELTSCALE Still effect the Line type scale of your geometry. You might need to use the REGEN or REGENALL command to see the result of any changes in your viewports.

MSLTSCALE

This is a reasonably new (Since 2007), but extremely useful variable. Like Paper space line type scaling, ModelSpaceLine Type Scaling only has two options. Setting MSLTSCALE to 0 (Off) is the default setting and will behave as Autocad always has.

Setting MSLTSCALE To 1 (On) will cause the Line type scale of any geometry in model space to be scaled by the Annotation scale. This allows you to have a preview of how the line type scale might look when seen through a scaled viewport.

MSLTSCALE Overrides LTSCALE and CELTSCALE in Modelspace, but it doesnt effect Paperspace, so it wont change how your geometry looks inside your viewports.

Using MSLTSCALE is a really good way of checking that your linetypes are going to look as you expect them to, without having to Flick back and forth between Paperspace and Modelspace.

Do you know how to which Linetype definitions you should use to meet the ISO Technical drawing standard? Read these posts on defining ISO linetype definitions to find out more.Technical Drawing Standards: Line colours.

January 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: Line Type DefinitionsShould you use colour line work on your drawings?

The British standards for technical drawing suggest that you dont use coloured lines on your drawings. This makes sense from a Setting out point of view, most of our drawings will be photocopied at some point in their life and the coloured lines wont show up.

The British standards do make a provision if you want to use coloured lines in your drawing, you just need to add a note or key to explain what the coloured lines mean.

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Do you use colour lines on your Drawings? Yes - It's in our company/industry/local standard

No - There's no point

No - But we should!

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NB: This has nothing to do with the colour of the lines that you see on your screen, only the printed output.

Image: FreeDigitalPhotos.netCheck out:

BS EN ISO 128-20:2001 Technical drawings. General principles of presentation. Basic conventions for lines

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Or read more posts onTechnicaldrawingstandards.Technical Drawing Standards: Line Type Definitions.

January 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: Line Type DefinitionsThe advantage of using the British standard is that the line type definitions have largely been coordinated in their meanings across the Industries.

Putting theLine types,Line weights andLine type scales together, we get the following Line type Definitions to use in our drawings.

I have amalgamated the definitions from the engineering drawing supplement and the construction drawing supplement together. The Line type definition numbers are my own.

Once again, you are free to make up your own line definitions, but it is recommended that you put a note on the drawing with their meaning.

BS 8888:2008 Technical product specification.


BS EN ISO 128-20:2001 Technical drawings. General principles of presentation. Basic conventions for lines


BS ISO 128-23:1999 Technical drawings. General principles of presentation. Lines on construction drawings


BS ISO 128-24:1999 Technical drawings. General principles of presentation. Lines on mechanical engineering drawings


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Comments

1. Anonymous says

May 2011 at 9:47 am

The Line weights ought to be in the ratio three:2:1. The additional line weight for construction drawings is used to represent graphical symbols and is situated somewhere between the a Narrow Line and a Wide line.

Reply Paul Munford says

May 2011 at 11:04 am

Thanks very much for your comment.

If you are looking for information on Line Weights, specifically you can find out more here:http://cadsetterout.com/technical-drawing-standards/line-weights/Cheers,

Paul

Reply2. Keith S. Angus says

June 2012 at 11:27 pm

So what are all these ACAD_ISO linetypes that we are offered? Which ISO, and why? Which industries are they used in? Im not aware of any standard that calls them up, and find I have to write my own line definitions to get anything sensible. Surely in these days of worldwide standards that shouldnt be necessary? (Im trying to decide if Im serious or joking when I say that but I really cant make my mind up!)

Reply Paul Munford says

June 2012 at 12:07 pm

Hi Keith,

This is from the ACADISO.lin file (2010):

ISO 128 (ISO/DIS 12011) linetypes have been added.;;;; The size of the line segments for each defined ISO line, is;; defined for an usage with a pen width of 1 mm. To use them with;; the other ISO predefined pen widths, the line has to be scaled;; with the appropriate value (e.g. pen width 0,5 mm -> ltscale 0.5).

I have no idea how much time and effort the CAD vendors spend keeping up to date with current standards!

Paul

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101 Inventor productivity tips AutoCAD Layering productivity, never use the Layers pull down again! AutoCAD Line Type Scales, the Secret Truth How to optimize your AutoCAD DWG drawing files The Secrets of copying Assembly filesTechnical Drawing standards: Line Types.

January 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: Line Type DefinitionsThe British standards give us fifteen line types to use. Not all of them have a specific meaning or at least they only have a meaning that is specific to the industry they are used in.

You are not limited to these line types. You can define your own, but the British standards require that you add a key to your drawing to describe your custom line types meaning.

BS 8888:2008 Technical product specification.Technical Drawing standards: Line weights.

January 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: Line Type DefinitionsThe British Technical Drawing standards allows for three Line weights on each drawing. However, this varies for each drawing discipline.

Engineering drawings only require two line weights, Construction drawings can have up to four Line weights.The Line weights should be in the ratio 4:2:1. The extra line weight for construction drawings is used to represent graphical symbols and is situated somewhere between the Narrow Line and Wide line.

The acceptable line weights (in mm) that can be used in a drawing are as follows:

0.18 | 0.25 | 0.35 | 0.5 | 0.7 | 1.0 | 1.4 | 2.0For the nerds among you the ratio between Line weights is 1:2 ( 1:1.4):You can use which ever group of line weights you like. You should base your choice on the size of paper and copying requirements.

Narrow (thin)Graphical symbolsWide (Thick)Extra Wide

0.130.180.250.5

0.180.250.350.7

0.250.350.51.0

0.350.50.71.4

0.50.71.02.0

if you only want to use two line weights, take the narrow and wide pair from each row.The default line weight in both Autocad and Inventor is 0.25mm.

The recommended Line weight for the Drawing frame (Border) for engineering drawings is 0.7mm. Im not sure how this fits in!

BS 8888:2008 Technical product specification.BS EN ISO 128-20:2001 Technical drawings. General principles of presentation. Basic conventions for linesBS ISO 128-23:1999 Technical drawings. General principles of presentation. Lines on construction drawingsBS ISO 128-24:1999 Technical drawings. General principles of presentation. Lines on mechanical engineering drawingsFrame.

August 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: Size and Layout of Drawing SheetsThe typical Engineering style drawing border has a grid reference frame drawn into the border. The grid references are used for the location and coordination of details.

Grid Line Weights

The Grid lines themselves are drawn with a 0.35mm line weight. They are spaced 50mm apart from the centring lines. The last two divisions can be whatever size they end up.

Grid References

The grid references start from the top left of the sheet, with letters running vertically from the top down and numbers running horizontally from left to right. On an A4 sheet the grids only need to be drawn on the top and left hand side. The letters I and O are not used because they could be confused with 1 and 0.

A3 Drawing Border with Grids Click to enlarge

The Number of Divisions depends on the Size of the Paper

Paper SizeA0A1A2A3A4

Long Side24161286

Short Side1612864

BS EN ISO 5457:1999+A1:2010 Technical product documentation. Sizes and layout of drawing sheetsTechnical Drawing Standards: Centring Marks

June 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: Size and Layout of Drawing SheetsThe BS ISO standards require Centring marks on Engineering Drawings.

If you are producing Shop drawings in the construction industry you may chose to use an Engineering or an Architectural style drawing frame. This a matter for your company standards.

Centring marks help to align the drawing when its being copied or microfilmed. If you want to include centring marks in your drawing frame, they should be 10mm wide and placed at the centre of each edge of your drawing frame. They dont have to be a single line, the design of the centring marks is up to you (go wild!)

BS EN ISO 5457:1999+A1:2010 Technical product documentation. Sizes and layout of drawing sheetsEngineering drawing frame border size

May 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: Size and Layout of Drawing SheetsThe size of the drawing border (or Engineering Drawing Frame) on your technical drawings is covered inBS EN ISO 5457.

The BS ISO standards require a 20mm border to the left hand edge (for filing) and a 10mm border round the other three sides of the drawing sheet.

Click Size and Layout of Engineering Drawing sheets for more ongrid reference frames and paper sizes.

For more information on engineering drawing layouts check out the Technical Drawing Standards Page!Technical Drawing Standards: Paper Sizes

May 2010 | Paul Munford Filed Under: Technical Drawing Standards Tagged With: Size and Layout of Drawing SheetsThe British (BS) andInternational(ISO) Standards give us a range of standard paper sizes to choose from.

The range is know as the A Size range. The Largest commonly used size is A0 which is a piece of paper 1m in area with the sides in proportion 1:2 ( 1:1.4).

A1 is half this size, A2 is half that, A3 is half again and A4 is half that. A4 is the smallestcommonlyused size for technical drawings.

Table of sizesDESIGNATIONLENGTHWIDTH

A01189841

A1841594

A2594420

A3420297

A4297210

Table of enlargement and reduction scalesFROM / TOA0A1A2A3A4

A0100%71%50%35%25%

A1141%100%71%50%35%

A2200%141%100%71%50%

A3283%200%141%100%71%

A4400%283%200%141%100%

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_1497963204.unknown

_1497963201.unknown

_1497963202.unknown

_1497963199.unknown

_1497963200.unknown

_1497963198.unknown

Technical Drawing Standards

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