Here's a vintage Hensoldt-Wetzlar 4x scope that presented with some very common issues (common to any vintage scope, not just this brand). The image was not clear, the vertical post of the reticle was bent, the focus ring screw had been replaced at some point with one that is incorrect, it was generally filthy and, last but certainly not least, the elevation drum lock screw was broken off (which is apparently very common).
The cause of the unclear image was a delaminated ocular (eyepiece) lens. These lenses are made in two parts (one concave and one convex) that are cemented together into what is known as an achromatic lens. An achromatic lens is designed to bring two different light wavelengths into focus on the same plane and, as long as the glue that holds them together is in good condition, light passes through it as if it isn't there. Once that glue deteriorates though, the light scatters, rather than passing through, causing a cloudy, smeared or otherwise distorted image. The solution is to dissolve the existing glue, clean the lenses and relaminate them, which is what I did. A likely reason for this not uncommon occurrence, is that these scopes are not sealed against the elements, allowing moisture infiltration into the scope (and the edges of the lenses). When everything is in good order though, some of these scopes provide a surprisingly clear image. Like any scope, it comes down to the quality of the glass.
Here, the failed lamination is apparent.
The next issue is to correct the misaligned post, seen here.
The remains of the broken elevation lock screw...I think that this one was broken during an attempt to remove it, without realizing that it is retained by a screw on the opposite side. It was twisted off right at the end of the retaining screw hole (the thinnest point)
Making the new lock screw (the focus ring screw is made on the lathe as well)...
Everything corrected, cleaned and ready for lubing and reassembly...
The finished job...
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