AllyCAD HOME Showcase

Modified Whistle Valve Design

An AllyCAD Home edition
Customer Showcase

Chris Parsons from the UK set about modifying a collection of old paper drawings with the intention of modifying the whistle valve design used on his model steam engine. He writes as follows:

"I imported a DXF copy of an original drawing because I wasn't happy with the design and I wanted to try two different methods of closing off the steam. The original drawing called for a steel valve and I wanted to try using a stainless steel ball bearing closing onto a neoprene 'O' ring or alternatively a neoprene bung to close off the steam.

I have used the AllyCAD CAD programme for many years and one of the main things I like about it, is the ease with which I can do geometric constructions, using existing lines when necessary to 'make geometry'. In this particular instance, I used the original imported drawing to 'make geometry' where appropriate and then deleted the original unwanted lines and used the geometry to build up the new design.

  As yet I have not had the opportunity to do more than bench test these valves, but these have been promising and I hope to fit them to my loco in the next few days and really steam test them.

Most of the original drawing, design and conceptualising was done in the comfort of my sitting room on my laptop and then transferred by USB stick to the workshop. It is extremely useful not only to be able to pick up dimensions on the workshop drawing, but I also greatly appreciate the ability to massively blow up the drawing by rolling the mouse button.

Another thing I like about it is to be able to switch the dimensions between imperial and metric. The original drawing was done on a different CAD package using imperial and hence I followed this in my own original redrawing. All my machines, however are set up for metric. By going to the settings menu, I can alter dimensions settings etc from inches to mm and almost by magic, all the dimensions on the drawing are changed to metric.

Click to enlarge

I have tried several other cad programmes but I am always happy to come 'home' to AllyCAD!!

It is my honest opinion that this programme at its present cost, is virtually ideal for the hobby model engineer like myself, where a lot of the components made are 'one off' originals. I anticipate that I may be demonstrating these units to my local model engineering society in the near future, where I will, of course, be using AllyCAD for the demonstration.

Thank you again for your help and support."

Block I, The Terraces, Steenberg Office Park, 1 Silverwood Close, Tokai 7945.
Tel: +27 +21 701-1850 Fax: +27 +21 701-1822
Web: Email: