[Boatanchors] Lubrication for Collins R-648

[Glenn Little WB4UIV]

There is a R-390A Y2K manual that is a corrected 
and improved manual based on the last R-390A manual printed.
There as also a R-390 group.
The recommendations for the R-390A gear train ( I 
assume the R-648 is similar) is to disassemble 
the gear train, clean the gears, burnish the 
burrs from the gears, reassemble the gears dry 
then lubricate with synthetic oil.
The bearings would be lubricated with the same oil.
Some recommend Mobile 1 or similar.
The reason for this type of lubrication is to 
reduce the caked on grease on the gears anf the 
rebuilt gear train turns very smoothly.
Some have had to add drag as the tuning racks in 
the R-390A have enough mass to move the gear 
train when properly cleaned and lubricated.


Hope this helps.


73
Glenn
WB4UIV


  At 11:08 PM 8/16/2015, John Saxon via Boatanchors wrote:
>Hi: I have a R-648 that needs gear lube job. Â I 
>have the manual and it specifies two lubricants: 
>MIL-G-3278 (gear teeth)MIL-L-7870 ( bearings). 
>What would I use for each? Many thanks,JohnK5ENQ 
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Glenn Little                ARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIV            wb4uiv at arrl.net    AMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)                      SBE ARRL  TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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