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Bogie pivot components are supplied in the
kit to mate with the M2 nuts fitted to the
tops of the bolsters
M2 x 10mm screws,
M2 x 6mm nylon insulators,
Brass tube 4mm OD x 3mm ID,
and M2 retaining washers (on the fret).
The diagram here shows the suggested pivot
arrangement to which the following instructions
apply. This arrangement is suitable for either
conventional or 'American' pick ups (with which
the bogie bolster is 'live'); the key attribute for
the latter being that the outer brass tube, and
therefore the loco chassis block, is electrically
insulated from the bolster top. The arrangement
also secures the bolster vertically, but allows some vertical movement to
accommodate adjustments in ride height.
Other arrangements are possible; the epoxy glue can be omitted and all components
can be shortened, for instance. If required, a thin insulating washer can then be
placed on top of the bolster to prevent electrical shorting to the brass tube.
Test the 4mm OD tube for a free sliding fit through the pivot holes in the loco's
chassis block. Open out the holes if and as necessary. Note that the fit is for the
tube passing perpendicularly through the hole; pitch and roll movements of the bogie
are not accommodated at this pivot.
Cut two sections of the 4mm OD tube about 4mm in length. Check that the nylon
insulat ors supplied are a free fit through the tube, opening out the bore if
necessary.
Remove the M2 x 5.5mm diameter washers from the main fret.
For each pivot, offer up one of the bolsters to the loco chassis, with the
'shoulders' at the tops of its traction ears resting on the sole plates, and tape it in
place temporarily. Slide a piece of 40thou plastic card between the top of the bolster
and the chassis, covering up the bolt hole. Put a ring of quick-set epoxy glue around
one of the 4mm tubes and place the tube through the pivot hole in the chassis to rest
on top of the plastic card, thereby positioning it about 1mm clear of the top of the
bolster. To make sure it is aligned correctly, when the epoxy is half set, untape the
bolster, pass the nylon insulator through the tube and secure it in place with the M2
screw and 5.5mm washer. Ensure that the bolster can rotate with the chassis sole
plates resting on its shoulders, and allow the glue to set completely.
Bachmann 47 Chassis Mods
25/52
(c) PenBits Model Railways, All Rights Reserved
04/05/2017