NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: C. Plath Sextants Mirror Adjustment
From: RS Peterson
Date: 2003 Sep 16, 21:41 -0500
From: RS Peterson
Date: 2003 Sep 16, 21:41 -0500
On Tuesday 16 September 2003 03:42 am, Kieran Kelly wrote: > > Note that Bauer's The Sextant Handbook cautions on page 55 that the > navigator must always loosen one screw when adjusting the mirrors on a > sextant before tightening the other otherwise the glass will break. Does > anyone know if this applies to the two adjustment screws on the horizon > mirrors of the Plath Classic and Professional sextants? Any help would be > appreciated. > This is not an issue with the CP Professional. The mirrors are spring loaded and do not require the loosen/tighten method. However, the big issue with these mirrors is corrosion of the stainless steel screws in the aluminum mirror housing. It can be a real show stopper as I have found out rebuilding several of these. Frequently, if you can get the screws out the sockets, the holes require retapping and sometimes the corrosion is too great and must be drilled and tapped oversize for a new, larger screw. Can be a real pain; I wonder if these out of production instruments are worth it. Given what I charged to rebuild I would recommend against the next time. Good luck. -- Robert S. Peterson 31 N Alfred, Elgin IL 60123 USA 847/697-6491 Compass Adjusting for Lake Michigan navigators since 1985 Physics @ Bartlett HS e-mail: rpeterson(at)enc.k12.il.us