{"id":697,"date":"2016-07-14T12:04:26","date_gmt":"2016-07-14T12:04:26","guid":{"rendered":"http:\/\/ngtrains-com.stackstaging.com\/blog\/?p=697"},"modified":"2020-10-31T13:07:44","modified_gmt":"2020-10-31T13:07:44","slug":"harping-on-about-switchstands","status":"publish","type":"post","link":"https:\/\/ngtrains.com\/blog\/harping-on-about-switchstands\/","title":{"rendered":"Harping on about Switchstands"},"content":{"rendered":"

For some years now I have sold the PSC cast brass switchstand kits but they usually sell out at the first show I attend and then getting more and in any quantity is a bit of a faff to be honest.\u00a0They have also been creeping up in price too.\u00a0\"Harp<\/a>For awhile I have been thinking there has to be a better way to supply these.<\/p>\n

This is the PSC switchstand kit.<\/p>\n

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The next question is do I replicate it or design another pattern. Some googling then found images and drawings<\/p>\n

\"Switchstand001\"<\/a>Well, in the end I decided that as the known demand was for ones similar to the PSC ones my first effort would be something very similar.<\/p>\n

First job was some 3D CAD.<\/p>\n

Drawn in SolidWorks this is also a 3 part kit with two halves of the base and the pole. There is a clevis shown in the drawing but this won’t be included in the kit.<\/p>\n

\"Clevis_image\"<\/a>The reason for not including it is one of the pitfalls of doing this stuff in CAD on a 24 inch twin screen is that you can zoom in and the thing looks huge but then when you actually get a 3D print in actual size it is a) a credit to the 3D printer for being able to print it and b) too tiny to commercially reproduce in brass.<\/p>\n

You’ll have to settle for making your own or just having bent wire.<\/p>\n

\"Switchstand002\"<\/a>From the 3D SolidWorks drawing STL files are created. These are the format that the 3D printer uses and they are e-mailed to the 3D printer of choice and then you sit back and wait for a week or so.<\/p>\n

Eventually a tiny box arrives with the postman which you open and realise that what looked huge on the screen is in reality tiny.<\/p>\n

\"Switchstand-assembled600\"<\/a>Prints tend to come in a translucent sort of colour which makes is difficult to see any of the detail so I usually just give them a waft of spray paint so you can actually see the thing before trying a test assembly.<\/p>\n

As long as you are careful you can build the model up and make any minor alterations you want. If major alterations were needed you’d just get it reprinted having made the alteration in CAD.<\/p>\n

So here we have the 3D print assembled.<\/p>\n

What next? well the 3D patterns have gone off to the brass caster of choice and we await their efforts. They will use the parts to make a cold setting silicon rubber mould of the parts. With the pattern removed the mould is then filled with moulten wax which is allowed to cool. This can then be done many times to make lots of waxes. Waxes can be joined by sprues to make on pattern. These joind waxes are then suspended in a mould frame and a ceramic type mould in liquid form is poured around it and allowed to set. The mould is then heated so that the wax runs out or burns off leaving a void in a mould capable of standing high temperature. Moulton brass is then poured into the moulds and allowed to cool after which the mould is broken away and the casting cleaned up.<\/p>\n

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For some years now I have sold the PSC cast brass switchstand kits but they usually sell out at the first show I attend and then getting more and in any quantity is a bit of a faff to be honest.\u00a0They have also been creeping up in price too.\u00a0For awhile I have been thinking there […]<\/p>\n

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