For this purpose use a thick gel-like axle grease or petroleum jelly, etc. Runny oils (such
as sewing machine oil) and WD 40 (or similar) are NOT recommended.
To apply grease:
Step 1. Remove the optical tube and slide and keep them safely to one side.
Step 2. Lower the focus platform as far as it will
safely
go. This will be when the large
part of the coarse focus gear just touches the large part of the intermediate focus gear
(see figure).
Do not try to lower the stage more than this or you will damage the gear
system
.
Step 3. For each of the the three corners in turn do the following (see picture on next
page):
Step 3a. Hold the stage upside down and with the your thumb on the focus nyloc
nut and your finger on the undersurface of the focus platform corner, squeeze your
finger towards your thumb so that you elevate the corner of the focus platform by
compressing the focus spring.
Step 3b. Ensure that the loose countersunk screw cup washer falls ‘down’ onto
the undersurface of the focus platform so as to expose the surface of the nut in the
focus pulley and the thread of the focus post bolt. With your free hand apply grease to
the focus bolt thread and the surface of the focus pulley nut. It may help to use an
applicator like a thin strip of plastic but whatever you use ensure that it does not have
free surface debris that could get into the bolt thread (for this reason cotton buds
should be avoided because loose cotton strands could build up in the mechanism).
Step 3c. Release the pressure you were applying to the focus spring so that the
corner of the focus platform returns to its normal position and ensure that the
countersunk screw cup washer rests evenly on the focus pulley nut (if it does not, re-
elevate the corner by applying pressure to the spring as before and then release it again
– repeat a few times until the washer lies evenly and flat on its focus pulley nut. You
may need to give the washer a little nudge while doing this if it doesn’t settle by itself).
PUMA Foundation Scope
Page 33 of 40
User’s Manual v1.0