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Stiff helical focuser
My Pentax 4" f4 Astrograph NDSFII has a 4" diameter helical
focuser that is difficult to turn. It is greased with a grey colored
grease. Whilst one can turn it with one hand at time it requires
two. The grease does not look like the black molybdenum
greases sometimes used on focusers. I would like to thin it
with a drop or two of very thin machine oil but having experienced
waxing of mixed greases in the past am hesitant.
Advice sought as what to do - Gerald.
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