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Another Criterion mystery

Started by fct-150, 04/18/2013 07:35PM
Posted 04/18/2013 07:35PM Opening Post
During my massive restoration of an already nice RV-6 from the very early '60s, I have come across a few interesting observations...

1) As Criterion RV-6(s) become younger in age, their focusers change. The U7 base goes from a 15oz iron base (1950s) to a 13oz iron base (early '60s), to a very light 7oz thinner aluminum base.

2) Earlier years RVs do not have sloppy die cuts in the oval pier feet. And in the earliest generations, the pier feet were painted black rather than sporting their "raw" aluminum look.

3) The first models used brass, not nickel plate hardware in the finder, focuser, and primary cell.

4) The first RV-6 models seem to have had a serial number aluminum plaque mounted on the tine saddle (riveted) and then a matching number aluminum plate by the focuser (flathead screws). As the models progressed, no serial number plates appear on the saddle and only a shiny metallic-like decal is placed by the focuser. Finally in the last years before B & L took control, there were no Dynascope decals at all.

5) The earliest of all models have perfectly cylinder-formed counterweights with a very fancy "Criterion 100" iron plate mounted via (2) rivets on the front side. As time goes on however, this counterweight changes in shape, having a "flat-side" to the back of the cylinder as well as "Criterion 100" being a barely legible font. And instead of being noted on a plaque, the "Criterion 100" is part of the counterweight itself; like a typewriter's dye.

6) The RV-6's motor housing cover use to have the word "CRITERION" deeply etched into the metal itself. All models passed 1962-63 have "CRITERION" as an aluminum or tin sticker decal.

7) The earliest years models had a hand torque lever that allowed the user to change altitude for polar alignment without having to use an Allen or hex bolt wrench. This same apparatus is present on the very old Sears and Tasco refractor mounts by Towa. But once I cross into the '64-67 years, this VERY nifty lever is replaced by the gigantic hex bolt. And what is very strange, the lever-style altitude adjustment cannot be adapted to the hex version...Those saddle tines have a completely different thread pattern. The lever will only work with the earliest years tines.

8) I'm not sure, but it seems very apparent that the first generation RV-6(s) had crystal clear rear primary mirror glass. The later years models had "frosted" or glazed-over" rear primary glass.

So in all my fun observations, I simply must ask the hiding guru out there; what does the "100" stand for in "Criterion 100"? And for that, what does "U7" stand for?

Ramble complete. I'm in hour 44 of my restoration. I'm waiting on the 22 karat gold-plated shaft collars to be completed. For those actually interested, this RV-6 will be present at Oregon Star Party this August.

All the best my friends,

Just a few thoughts:

8) FS-152SV sitting in the office
grin Japanes super lucky zen observatory garden
:S Meade ETX-90 finder scope position
shocked Hino Optical Mizar 120SL observatory model
:C SR-4mm eyepiece with a 3x barlow in a 60mm refractor
8O Zeiss Victory 7x42 SFs
wink Having over 135 vintage oculars to play with
smile My life surrounded by wonderful friends and impeccable optics
Posted 04/19/2013 10:32PM #1
Post some pics when you are done!