NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Construction of Sextant Arm Pivot Questions ?
From: Greg Rudzinski
Date: 2007 Nov 08, 15:21 -0800
From: Greg Rudzinski
Date: 2007 Nov 08, 15:21 -0800
The index arm on my 1970 M.Low U.S. Navy Mark 3 has a single pin with two separate cone tapers of the same brass material as the frame bearing. Normal wear should seat the tapered pin further into the frame keeping the system snug. A pin retainer screw holds everything together and sets bearing tightness. Greg Rudzinski On Nov 8, 5:06 am, Robert11wrote: > Hello, > > I guess I should introduce myself, somewhat. > > Am a retired research engineer, and have always been interested in > navigation, but, unfortunately, more on the theoretical than the > actual "doing" side. > > However, I did complete the two celestial navigation courses given > many, many, years ago by the U.S. Power Squadron, which included the > taking of many sextant sites. Can't remember when i enjoyed any > courses more. > > I don't really have the opportunity to inspect any sextants now > firsthand, but am quite interested in how these folks did, and > presently are, designing and fabrication the pivots for the arms. > > Are they just a bored, and subsequently honed, hole for a steel pin ? > > Is it a cylindrical hole, or tapered ? > > Is there any "preload" to minimize wobble or looseness with wear ? > > Different mfg's doing it differently ? In the past ? > > Any good detailed pix available ? > etc. > > Great Group; have learned much. > > Regards, > Bob (Sudbury, Mass., USA) --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---