Sick of centre punching off the mark, I made this optical centre punch yesterday. The body is stainless, the punch I turned down from a pin punch and the lens from a bit of 10mm acrylic. No convex lensing - don’t see the need yet; plus, I haven‘t a clue how to do it. After cutting to length I chucked the acrylic and turned it down with a sharp bit, then polished it with the back of a sheet of wet and dry dipped in Brasso. Rather than cross hairs I marked the centre at each end. In use, line up the centre marks over the lines scribed on the material, replace lens with punch and tap. Seems to be accurate, certainly more so than doing it by eye only. In the picture you can see the top lens centre mark (blury) at 3 o’clock, just to the right of the lower lens mark.
This was originally just a try and see job, using 6mm acrylic. The 6mm acrylic proved too small: not allowing enough light in and making it difficult to find the scribed lines so I substituted 10mm acrylic. Now it know it works I might make up one with a wider brass base.
This was originally just a try and see job, using 6mm acrylic. The 6mm acrylic proved too small: not allowing enough light in and making it difficult to find the scribed lines so I substituted 10mm acrylic. Now it know it works I might make up one with a wider brass base.
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