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Trig Columns


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Trig columns are a regular feature found in the UK countryside. Generally found on the tops of hills but can really be found almost anywhere that had [when erected in the 1930s] clear lines of sight to other exposed areas. These days their function has been supplanted by aerial photography and GPS mapping so the concrete columns can be a bit eroded and grubby. The most common sort is the tapering white concrete column about four foot tall which sits on a concrete box that is usually buried but may or may not be exposed - especially on eroded peat moors.

They were used essentially as known positions from which theodolite sightings could be made to similar structures at some distance away. Each one contains a bronze bench mark and ID plate with a brass/bronze sighting arrangement on top.

Most, but not all, are marked on OS maps by a small triangle with a dot in the centre. One that isn't marked is S2640 at grid SE 08013 00439 about a mile to the NE of Crowden.

I measured this one [pictured below] and have produced a couple of 3D printed 4mm versions that now grace Churminster and Stowe Magna but 7mm cast resin versions will shortly be available from Radley Models. A picture of the 7mm master is attached.

 

 

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Edited by Arun Sharma
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Being a simple shape with a slight chamfer on the sloping edges, it lends itself to home resin casting. Here is the master with a few of its resin clones and the mould.

 

Trig Col.JPG

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5 hours ago, DGO said:

Looks good, was Lego involved in the mould making process by any chance ?

Yes-the resin mixture doesn't stick to the plastic used in Lego blocks. Lego blocks also produce a pretty good seal between layers.

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  • 4 weeks later...

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