Drafters Forum | JOBS | Drafting Standards | Funnies | Technical Dictionary | AutoCAD Tutorials | Free Lisp | Free Blocks

ARTICLE: Top ways drafters can make money online with Freelancer.com

Dimensioning (Metric)

From Draftsperson.net

Revision as of 03:10, 31 October 2011; view current revision
←Older revision | Newer revision→

By Steve

Dimensioning practices for metric drawings are similar to those for non-metric drawings, but there are some subtle differences.

This material outlines the current practices.

Dimension Lines and Projection Lines

Projection lines are used to indicate the extremities of a dimension. They are generally drawn up to 1 mm from the outline of the object.

Dimension lines are used to label a particular dimension. They have one or more arrowheads, which are typically 3 mm long x 1 mm wide.

Thin type B lines are used for both projection lines and dimension lines.

Image:Dimlines.gif

Linear Dimensions

Generally linear dimensions are in millimeters (millimetres).

To avoid having to specify 'mm' after every dimension, a label such as 'all dimensions in mm' or 'unless otherwise stated all dimensions are in mm' is usually contained in the title block.

If the dimension is less than one a leading zero should be used before the decimal point.

eg. 0.5

After reduction to microfilm and subsequent re-enlargement, the decimal point may sometimes become unreadable. To avoid possible misreading of the dimension a comma is often used instead of a decimal point.

eg. 0,5 25,7

Angular Dimensions

Angular dimensions are usually specified in decimal degrees, degrees and minutes, or degrees minutes and seconds.

eg. 27.5° 27°30' 27°30'16"

If the angle is less than one degree a leading zero should be used.

eg. 0.5° 0°30'

Dimensioning Methods

Two methods of dimensioning are in common use.

Unidirectional The dimensions are written horizontally.

Image:Dimuni.gif

Aligned The dimensions are written parallel to their dimension line. Aligned dimensions should always be readable from the bottom or the right of the drawing.

Image:Dimaligned.gif

Overall Dimensions

When several dimensions make up an overall length, the overall dimension can be shown outside these component dimensions.

When specifying an overall dimension, one or more non-critical component dimensions must be omitted.

Image:Dimoverall.gif

Auxiliary Dimensions

When all of the component dimensions must be specified, an overall length may still be specified as an auxiliary dimension.

Auxiliary dimensions are never toleranced, and are shown in brackets.

Image:Dimauxiliary.gif

Dimensions not to Scale

Dimensions that are not to scale are underlined.

Image:Dimnottoscale.gif

Dimensions not Complete

When a dimension line cannot be completely drawn to its normal termination point, the free end is terminated in a double arrowhead.

Image:Dimincomplete.gif


Need drafting work?

We are having great success with Freelancer.com. With this website we can win all types of drafting work. People from all over the world are looking for freelancers skilled in AutoCAD, Revit, Civil 3D and Microstation, are you one of those people? If so you can live the freelancer lifestyle! and work from any location you want too. Freelancer.com, it works really well - we like it - and we believe you will too.

Looking for CAD drafters?

With modern construction, software and increased legal requirements, we often require specialized assistance with our projects. Putting skilled staff on full time is not always economically feasible for small businesses. Freelancer.com solves this problem. On this website you can engage skilled drafters. Either on fixed prices for specific tasks, or reasonably priced hourly rates for longer term contracts.

E-book: AutoCAD Block Best Practices

We draw repetitively when using AutoCAD. If we manage the drawing elements as reusable contents, it will increase our productivity significantly. Not only can we draw faster, we can add information to our blocks. Which allows us to generate useful reports. This is what Edwins e-book entitled AutoCAD Block Best Practices is all about. Yes, increase your productivity with the block!



Printable version

Toolbox

Views

Main Page | Free AutoCAD Blocks | Free Revit Families | Funnies | Drafting Standards | Drafting & CAD Forums | Structural Drafting | Technical Dictionary

Personal tools

MediaWiki