DUPONT  - REFRIGERANTS- This is a genuinely free software suite that allows you to find the properties of a whole range of refrigerants and refrigeration cycles. Requires you to register, download and install. It really is free and works.

ARCHON ENGINEERING  - Many suites of programmes for mechanical and civil engineers available to download as demo versions includes an excellent programmes for solving beam, torsion and frame problems. Lots of stuff on American steel sections but not for European standards. Also contains steam tables and much more. Well worth a visit. The software is easy to use.

Bishop Wisecarver - BWC specializes in linear motion bearings, linear slides, rotary tables, systems and components

EFUNDA - A great  web site with lots of information and tools on most mechanical topics. Requires a registration fee.

ENGINEERING TOOL BOX -  A free and useful web site with calculator tools for most engineering design problems.

A wealth of mathematical help is available here

Motion-controller.machinedesign - A new professionally designed site, which offers valuable information on motion controllers, programmable logic controllers and other types of controllers.  The site is considered to be a valued resource for design engineers.

TPUB  -  Contains free tutorials on various engineering topics.

PNEUSIM - AUTOMATION STUDIO  - This is a very powerful design suite for pneumatics, hydraulics and electronic/electrical circuit design. It enables you to design circuits and produce drawings to the correct standards. It also allows you to simulate the design to see if it works. Contains picture libraries and explanations of the hardware. It can be interfaced to real hardware. Allows control circuit to be designed in American and European ladder logic symbols. It also allows control circuit design using Grafcet. Also has electronic logic circuit design. I have used this software widely and fully recommend it to fluid power control system designers.