[ARC5] [OT] B-52 Periscopic Sextant Azimuth Crank Lock?

[D C _Mac_ Macdonald]

Does anybody know of a repair/calibration source for the USAF MA-2 sextants by Kollsman Instruments on which the periscopic sextants were based? These were hung in the sextant bubble on top of the aircraft.  
 
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* 73 - Mac, K2GKK/5 * 
* (Since 30 Nov 53) * 
* k2gkk hotmail com * 
* Oklahoma City, OK * 
* USAF & FAA (Ret.) * 
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> From: scottjohnson1 at cox.net
> To: brooke at pacific.net; arc5 at mailman.qth.net
> Date: Tue, 27 May 2014 18:02:52 -0700
> Subject: Re: [ARC5] [OT] B-52 Periscopic Sextant Azimuth Crank Lock?
> 
> Brooke-
> There should be a little lever on the mount that locks the azimuth scale, so
> you can set it to the aircraft heading relative to the sextant position  (it
> locks the sextant into position, but the the crank does not move the
> sextant).  BTW, it would probably be more useful to have the top section
> (shutter) that is used on the C-130/KC-135 (and most others) , as they don't
> have the drastic wedge shape that blocks the view to the aft at low angles
> of declination.  I might have an extra here.  Also, the sextant with the
> electronic averager is way cool!
> 
> Scott W7SVJ
> 
> -----Original Message-----
> From: ARC5 [mailto:arc5-bounces at mailman.qth.net] On Behalf Of Brooke Clarke
> Sent: Tuesday, May 27, 2014 4:39 PM
> To: arc5 at mailman.qth.net
> Subject: [ARC5] [OT] B-52 Periscopic Sextant Azimuth Crank Lock?
> 
> Hi:
> 
> After years of looking I now have, at the same time, a periscopic sextant
> and the mounting hardware used for a B-52.
> The problem is although the azimuth crank turns the Veeder-root counter it
> does not turn the sextant.
> There is a ring that's the lowest part of the mount that says "LOCK -->",
> but I don't see how to lock it.
> Maybe there's a missing pinch screw?
> http://www.prc68.com/I/S5807.shtml
> 
> -- 
> Have Fun,
> 
> Brooke Clarke