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
8/52
(c) PenBits Model Railways, All Rights Reserved
04/05/2017