Bearing Carriers
This stage of the assembly is fixing the subframe bearings into the bearing carriers
and folding up the carriers around the bearings. The carriers are located on the fret
in four frames, each of which folds up into a jig to help to fix the bearings in the correct
place. The carriers are a little fiddly, but worth spending time to get right as they are one
of the main functional parts of the suspension.
We find it useful to use two containers to store separately the components of each
bogie; 1kg margarine tubs are suitable. Within them we have 35mm film cannisters,
one for each axle, to keep the components for each wheelset together. We mark the
containers and cannisters to match the id marks etched on to the subframes, bolsters and
bearing carriers as explained below.
Separate the two subframe etches from the
fret.
Remove
any
other
components
contained within each subframe etch and store
them safely.
Note that one of the subframes is
marked with a small triangular dimple.
You will find that one of the bolsters, and one
set of bearing carriers, are similarly marked.
You can use the marks, through all subsequent
work, to distinguish the components of each bogie.
Take one of the twelve axle bearings and test it in one of
the subframe axle slots. It should be a free sliding fit but if
it's a bit loose don't worry. It will more likely be a little tight in
which case gently file the vertical sides of the bearing slot -
take off a little at a time equally from each side and try to keep
the two sides vertical - until the free sliding fit is achieved for
the entire depth of the slot. Now test fit the other 11 bearings in the same slot. You
should find that they are all about the same size. If there is a variation, then you may
wish to individually fit the bearings to the slots. You will then need to preserve the
identity of each bearing through subsequent operations (there are marks etched on the
bearing carriers and the subframes to assist with that - see below). But do bear in mind
that, as we have no coupling rods, the accuracy of this fit is by no means as critical as it
would be if we were building a steam locomotive. Whatever you choose to do, dress the
remaining eleven bearing slots to get the free sliding fit for each of the bearings.
Put the subframes in their containers safely to one side for now.
Test fit the axle bearings on the 2mm replacement axles. They should be a free
running fit. Remove any burrs or swarf from the front and rear faces of the bearings.
Bearing Carrier Instructions for Six-wheel Bogies
11/60
(c) PenBits Model Railways, All Rights Reserved
27/09/2021
Summary of Contents for Bachmann Class 66
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