Building a fence

Round Posts

Diameter Area %age of 4" post Breaking Force %age of 4" post
2.5" 4.91 39% 238 lbs 25%
3" 7.07 56% 408 lbs 42%
3.5" 9.62 77% 650 lbs 67%
4" 12.57 100% 970 lbs 100%
5" 19.64 156% 1893 lbs 195%
6" 28.27 225% 3268 lbs 337%

Posts should have approximately 1/3 of their length in the ground

Freeware CAD Packages

I needed to use some draughting software recently and scoured the web for a decent CAD package. In the end, I found useful reviews of several freeware packages by someone called NHCAD. Their favourite program was Turbo CAD Learning Edition. However, the latest versions are time limited, so they recommended downloading an earlier version (V4). The program can be downloaded from sfasu.edu and you should also download the pdf documentation CompleteGuideToTurboCADv4. If you decide to buy a copy then visit TurboCAD’s website.

I downloaded and tried several packages including

The worst packages were WinCAD and KitCAD, while the run away winner was Solid Edge 2D despite its massive 233MB download (due to the inclusion of Microsoft’s .NET Framework 2.0). Turbo CAD Learning Edition is good and a much smaller download (at ~16MB) while bCAD is useful for its 3D capabilities; the only drawback being its limitation of only being able to save drawings with less tham 37 entities in the demonstration version. I have not spent enough time with AllyCAD and A9Tech to form much of an opinion on these, although AllyCAD feels competent and is being taught in all South African schools, so should be actively supported for a while. They also have plenty of online tutorials. A9Tech felt as though they were trying to emulate AutoCAD, but didn’t draw me in.

Other SourceForge packages you might consider are

  • BRL-CAD, a powerful cross-platform constructive solid geometry solid modeling system that includes an interactive
    geometry editor, ray-tracing for rendering & geometric analyses, network distributed framebuffer support, image and signal-processing tools.
  • FreeCAD, an Open Source CAD/CAE, based on OpenCasCade, QT and Python. It features some key concepts like
    Macro recording, Workbenches, the ability to run as a server and dynamicly lodable Application extensions which is designed to be platform independendent
  • avoCADo, another Open Source (GPL) 3D CAD design and modeling program which aims to be an indispensable collaborative tool with an intuitive user interface for both engineers and artists alike.

The Autodesk Design Review packages simply allow you to open various CAD drawings and annotate them, they do not allow you to design anything. This may be useful if you wish to distribute your drawings for comment or approval. You may also download and install Autodesk’s DWF writer which will let you create suitable files from any application by simply printing the document.

If you are after tutorials, then try CAD Digest or Winston.

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