PenBits Bachmann Class 66 User manual

ASSEMBLY INSTRUCTIONS
PK018
SPRUNG BOGIE KIT
BACHMANN
CLASS 66
PenBits Model Railways
www.penbits.co.uk
c/o 12 Fieldside, Long Wittenham, ABINGDON, Oxon, OX14 4QB

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Table of Contents
Table of Contents
General Notes
A Few Words …
Safety
The Instructions
File Format
Structure
Printing
The Etches
Tags
Slots
Degree of Etching
Cusps
Folds
Soldering
Spring Winding
Warranties
Bearing Carriers
Bachmann Class 66: Subframes
Bachmann Class 66: Bolster
Bachmann Class 66: Modifying the Bogie Drive
Dismantling the loco
Dismantling the Bogie
Modifying the Drive Train Mouldings
Reassembly
Bachmann Class 66; Preparing the Locomotive
Fitting Wheelsets
Bachmann 66: Springs, Bogie Assembly and Rolling Test
Bachmann 66: Cosmetic Sideframes
Pickups and Power
Bachmann 66: Final Assembly
Replacing the Worm Drives
Assembling the Bogies
Checking Clearance over Worm Cover
Fitting Etched Worm Cover (if required)
Final Assembly
Table of Contents 3/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

General Notes
A Few Words …
Safety
The Instructions
File Form a t
Structure
Printing
The Etches
Ta gs
Slots
Deg ree of Etching
Cusps
Fo lds
Soldering
Spring Winding
Warranties
A Few Words …
These advices, taken, several moons since, from John Lythgoe's instructions for his Formil
Model Engineering Dyna-drive kits, have proved to be useful and enduring tenets:
"Proceed with patience and due care at ALL stages and a free-running locomotive
should result."
"Allow sufficient time to spread the conversion over a number of modelling sessions."
"Work in good light conditions. Use an anglepoise-type lamp if possible. A self-
supported magnifier is a useful aid."
Safety
Our kits are intended to be assembled by adult modellers, with some workshop experience
and awareness, who are able to exercise due care and attention when handling the
materials and carrying out the various operations involved. Many of the metal components
have sharp edges. Chemical products used in assembly can be injurious through contact
with skin or eyes, ingestion or inhalation. Some processes involve high temperatures. The
user should be aware of and follow the manufacturers' or suppliers' safety data and
instructions for all tools, materials and products.
The Instructions
File Format
The instructions are available on line in both HTML and pdf formats. The HTML
versions have one page for each major section, whilst the pdf versions have a
single file for each kit.
Structure
General Notes 4/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

We've divided up the instructions into "narrative" paragraphs, like this one, which
indicate what is being accomplished by a particular stage,
"instruction" paragraphs, like this one, with the tick-box; "box-ticking" not our
favourite activity perhaps but nonetheless can be useful, on a printed copy, for
recording progress and making sure nothing is forgotten,
and "advisory" paragraphs, like this one, which pass on techniques that we found
useful but aren't necessarily the best way, or the only way, of achieving a result.
Printing
We have introduced a "Check List" for some of the kits, which contains the texts of
all the instruction paragraphs for the kit. This is a great deal more compact for
printing than the full instructions, and perhaps more suitable for the workshop. The Check
Lists are available only from the on-line copy of the instructions, from this Index Page.
We intend the Full Instructions to be viewed 'on-screen'. If you did need any of the
diagrams or pictures in the workshop, you could download and print them individually
(from the HTML instruction pages) to complement the Check List.
The pdf files can be printed in full or in parts to your own printer using your pdf
viewer. Full printouts in booklet form can also be produced using third party services.
For more information visit our Printing the pdf Files page.
If you wish to print out sections of the HTML instructions, they are formatted in
standard HTML/CSS but, even so, the print function in some browsers does a better
job of rendering them than others. We find that 'Print' function of the Google Chrome
browser produces a good printed result: it also gives the option of 'Save as PDF', which is
a convenient way of creating a single portable file, including all the illustrations, which you
can view or print on any device.
If your printer can produce half-size A5 prints (two per A4 sheet) or, better still,
double-sided A5 booklet printing, using those options can save a great deal of paper.
The Etches
Tags
Components are attached to the fret by small
half-etched tags. These can be cut through
using a heavy craft knife with an old, stubby,
blade (avoid the thin, pointed, 'scalpel' types,
as they will break), against a hard surface. We
keep a rigid Stanley knife expressly for this
purpose, with an old carpet trimming blade
ground to shape as shown.
Any remnants of the tag may be cleaned up
using a flat file. We have tried to avoid putting
tags on mating faces, but there are some
instances where they need to be removed
General Notes 5/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

thoroughly.
Slots
Some of the parts of our kits are designed to
fit, perpendicularly, either into or through slots
i n other parts. The slots are intended to
provide a loose sliding fit for the other part.
Because of variations in the degree of etching
(q.v., below), it is possible that the fit will be
looser or tighter than ideal.
Check the width of each slot with a piece
of scrap etch before assembly, preferably
before folding the slotted part. If the scrap will
not pass through, hold it in pliers or a hand vice, as shown (though make sure the part is
well supported), and work it through the slot until the loose sliding fit is achieved. In tight
spots, it is possible to use a small drill held in a pin chuck as a file.
Degree of Etching
The etch is created for us by a third party industrial manufacturer using a process of
chemical erosion. The 'Degree of Etching', i.e. how long the metal sheet is left in the
chemical bath, is a variable which is set by the skill and judgement of the operator as
each batch of sheets is produced. That dictates that the sizes of the etched parts on
different sheets can vary, within a certain tolerance, around the nominally designed
values. The variation is more significant with the relatively thick materials, that we use in
the main structural parts of our kits, than it is with the thinner materials typically used for
detail parts.
The ideal degree of etching is indicated by the slots (see above), as manufactured, being
just slightly on the tight side of the easy sliding fit required. The range of degree of
etc hing which we deem to be acceptable is from a 'lighter' etch, in which the scrap
material has to be pushed through the slot quite firmly to achieve the clearance, to a
'heavier' etch, where the fit is a little loose. We have test built our kits from etches
across this range to confirm that they may be assembled successfully.
Cusps
The chemical erosion process works equally
from each side of the metal, resulting in the
edges of the etch having shaped 'cusps' as in
the diagram here. On edges which will be
visible on the finished model, it is good practice
to file the edges of the metal flat. Many of the
edges on our kits are hidden from view.
Where edges form joints with other
components, on a 'lighter' etch the edges may
need to be filed to a flat surface to achieve a fit, whereas with a 'heavier' etch one might
leave more of the cusps in place. In places which can't be reached by a file, e.g. in acute
corners of the etch, the cusp may be pared away with a sharp knife.
General Notes 6/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

Folds
Folds are indicated on the etches by half-
etched lines. Unless stated otherwise, all folds
are made at 90° with the half-etched line on
the inside of the fold. Most folds may be made
by holding the larger part of the workpiece in
the fingers or, for smaller items, a hand vice or
similar clamp, and then driving the fold from the
smaller part either by using smooth-jawed
pliers or by turning it over against a smooth,
flat, hard block of material such as hardwood,
metal or tufnol. For longer folds the workpiece
may be clamped between two flat, straight
edged pieces of similar material. Special folding
tools or bending bars are not necessary,
though of course you may find them useful if
you have them.
Whichever way you make a fold, try not to force its location or direction, but let the brass
bend at its weakest point as determined by the centre of the etched fold line. This should
result in a correctly positioned and symmetric fold as shown in the diagram.
The act of making the fold will work-harden the metal along the line of the fold and may
even, especially with a lighter etch, cause it to yield on the outer corner of the fold. Try,
therefore, not to work a fold unnecessarily once made, as it will become increasingly
brittle and prone to breakage. In general, folds are reinforced with a fillet of solder but
this is explicitly dealt with in the instructions for each component.
Soldering
We use Carrs 145° wire solder with either Carrs Green Label liquid flux or La- Co paste
flux, except where stated otherwise. You will develop a technique that suits yourself
and your iron, but the following notes might help as a starting point.
Flux can be applied to the workpiece using a brush, a pointed cocktail stick or (for
paste flux) a syringe. With liquid flux, reducing the surface tension of the flux, for
example by adding a drop of washing up liquid or ox-gall, may help it wet the surface. The
soldering iron bit is wiped on a damp sponge before each use. A small amount of solder
can be picked up on the bit (it might need a little flux to help it) and the bit applied to the
workpiece, holding it there until the solder 'flashes' off the bit into the joint; we are using
relatively thick material so can afford to linger with the iron and get plenty of heat to the
job. Alternatively a small length of solder wire can be cut off, placed next to the joint and
the iron brought to it. The length can be anything down to the smallest sliver (and even
that cut into smaller sections), giving precise control of the amount of solder applied.
Flux residues should be neutralized and/or cleaned off after each working session.
Green Label flux may be rinsed away with water; a little added citric acid will neutralize
it. Liquid or paste fluxes can be washed away either with a proprietary flux cleaner or a
50/50 mix of methylated spirits and water.
General Notes 7/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

Spring Winding
This section describes a method for producing coil springs, for cosmetic detailing, from
wire. The example shown uses 0.6mm brass wire formed around the shank of a 1.4mm drill,
other materials, e.g. steel or copper, can be used. Such springs will also work functionally,
though note that steel of the correct scale diameter tends to be too stiff.
The drill, forming the armature around which
the spring is to be wound, is clamped firmly
into the lathe chuck with its shank protruding.
The free end of the shank is supported by the
chuck in the tailstock, lightly clamped.
Start with a bend at the end of the wire to
form an anchor. Catch it either between the
jaws of the chuck (if they are far enough
apart), or (for smaller wire and armature diameters) within the flutes of the drill.
Using a pair of pliers to apply tension, rotate
the lathe chuck by hand to wind the wire
around the armature. Pay heed to the direction
of winding - a surprising number of diesel
bogies were fitted with left-hand wound coil
springs (sometimes with a duplex right-hand
wound coil within).
As you continue to rotate the chuck, vary the
tension and angle on the wire to get as close
as you can to the desired coil spacing (you can
adjust this later, but it's best to get as close
as possible to start with).
Keeping the coil on the armature, you can
stretch or compress the spring axially to get
the coil spacing you need.
General Notes 8/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

You can also use a tool such as a screwdriver
or knife blade to get the spacing. If you have
enough hands, you can do this as you wind the
spring.
Slide back the tailstock and release the spring
from the chuck.
Trim off the waste at the ends of the spring.
File the ends of the spring flat, using the free
end of the armature to support it.
Reset the armature in the chuck to the desired
length of the spring.
General Notes 9/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

Cut the spring slightly overlength and file the
cut end flat using the armature as a support
and length gauge.
Little beauties. Results improve with practice -
all very therapeutic!
Warranties
The procedures described in our instructions require the proprietary locomotive to be
dismantled and some of its components to be modified. The manufacturer's warranty will
almost certainly be rendered void by carrying out the modifications. The user should
ensure that the locomotive is free running and has no warranty issues before commencing
work.
Please follow the manufacturer's instructions for the dismantling of the locomotive.
Our instructions guide you in making modifications to components of the locomotive and
fitting the kit. The modifications, the kit and the instructions have been tested by the kit
designer and others to confirm that they are practical, serviceable and, when used as
intended, produce a working locomotive whose performance will bring much pleasure.
However, as the fitting of the kit by the user is out of our direct control, we can make no
warranty, expressed or implied, as to the performance and continued serviceability of the
locomotive following modification.
General Notes 10/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

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

Remove the bearing carrier frames from the
main etch. DO NOT at this stage separate
the bearing carriers from the frames.
Note that the individual bearing
carriers each have small half-etched
identification marks. You can use these in
conjunction with corresponding marks on
the subframes to ensure that each carrier
is always mated with the same subframe
slot.
Note that the identification marks
may be on the inside or the outside
of the carriers, depending on whether the
carriers face inwards or outwards in the
subframes. The photos in this section
show outward-facing carriers, used in all kits except for the Class 52.
Test fit the bearings in the large central
holes in the carriers. The body of the
bearing (excluding the flange) should pass
through the hole. If necessary, gently relieve
the holes with a round needle file, working
evenly around the edges, until the bearings
pass through.
The folds in the bearing carrier frames
are best made in bending bars, or
between any two trued and parallel surfaces
clamped together. Use a rigid piece of flat
material to make each bend simultaneously
along its whole length. This will help minimise
any unwanted distortion in the fret.
Note that Fold 3 is a jig fold, made along the tags at the base of the carriers.
Bearing Carrier Instructions for Six-wheel Bogies 12/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

Make Fold 1, check that all sections of it are at 90°,
and reinforce it with solder. Be sparing with the
solder; you don't really want to get any on the carrier
faces to the inside of the fold. Apply a small amount of
liquid flux to the slots on the outside of the fold, then
get a small amount of solder on the iron and touch it
against the central slot on the outside of the fold on
each bearing carrier. You will see the solder flash along
the joint to the other slots. Repeat for the two sections
of fold on the carrier frame.
Make Fold 2. You will need a thin, firm, flat piece of
material to drive this fold; a robust steel rule (not a
thin springy one!) works OK. If anything, overfold beyond
90° just slightly.
Make Fold 3, to approximately 45°. Note that this fold
is along the line of the tags at the base of each
carrier, forming part of the frame assembly jig, and is not
a part of the finished carriers.
This is a view of the folded carrier
frames. Fold 3 has been made to 90° in
this case, but anything over about 45° will do.
The photo shows outside-facing carrier
frames, used in most of our kits. For
inside-facing frames (used on the Class 52),
the half-etched id marks are on the faces
visible in the photo.
Stick a length of double-sided tape, large enough to take one of the carrier frames,
onto a clean, flat, heatproof working surface. Ensure the tape is firmly smoothed down
Bearing Carrier Instructions for Six-wheel Bogies 13/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

on the surface, with no air bubbles or foreign bodies trapped underneath.
Remove the backing paper from the tape,
take it to one side and place on it three of
the axle bearings, flanged face down. Place the
carrier frame, inverted as shown, over the
t h r e e bearings with the bearings passing
through the three holes. Use the backing paper
to carry the three bearings and frame on to
the double sided tape, then slide the backing
paper away, leaving the three bearings in
contact with the tape and held in position by
the carrier frame. Press the bearings firmly into
place on the tape and remove the carrier frame. Repeat for the other three carrier frames.
Using a cocktail stick, place a thin fillet of multipurpose grease around the flange root
of each bearing. This will ensure that the area is kept free of solder when the bearings
are fixed into the carriers. An alternative is to use a permanent marker: the ink should
resist the flow of solder.
Place the carrier frame, the correct way
up, over the bearings and press down
firmly the back of the frame and carriers,
above Fold 2, on to the tape, as shown
here. The unflanged end of each bearing
should protrude from the face of its carrier
by a very small amount (not quite as much
as in the sketch), and the faces of the
carriers should be parallel with the end faces
of the bearings.
Using a cocktail stick, apply a small amount
of flux around the join between the
protruding part of each bearing and the face of
its carrier. Holding a bearing in place with a
heat insulating instrument, to make sure it
doesn't move, bring the iron with a small
amount of solder to the join between bearing
and carrier, and let the solder flash round the
joint. Repeat for the other bearings. A small
amount of solder may appear on the bearing
outer surface under the inner face of the carrier but most of the bearing outer surface, in
particular within about 0.5mm of the flange, should be free of solder.
Remove any excess solder from the front faces of the bearings.
Free the fret from the working surface.
Weaken the bond of the double sided tape with a soak in methylated spirits and slide a
Stanley knife blade or a similar thin strip of metal under the fret and bearings to break
the bond of the tape without causing too much distortion.
Unfold Fold 3 and separate the individual bearing carrier assemblies from the frame.
Take care, as the top parts of the carriers are quite fragile at this stage: it may be
Bearing Carrier Instructions for Six-wheel Bogies 14/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

best to leave cleaning up the tags until after the folding and soldering stages below.
Taking each carrier in turn, clamp it firmly
into a vice (a hand-held vice is ideal for
this) across the ends of the bearing with the
bottom of the bearing carrier protruding. File
away any remnants of the tag from the lower
edge of the carrier.
Working against a hard, flat surface, make
the fold to form the bottom flange of the
bearing carrier.
Then, invert the carrier in the vice so that
the carrier top is projecting. Fold in the
ears at the top of the carrier. You may find
that the ear catches against the top flange:
do not apply brute force, but adjust Fold 2
and/or the direction of the applied force, and
you will find that it folds easily. Folding against
a block, as shown, gives a good, tight fold.
On the inner carriers (the ones without a
hole in their back face), apply a small
amount of flux (cocktail stick!) to the folds and butt joints around the top of the carrier
and flash in some solder to reinforce the folds and form a fillet between the lower edges of
the ears and the top of the carrier body. Clean off any solder which adheres to the outer
faces of the ears. Ensure the holes in the ears remain clear of solder.
On the outer carriers, pass a piece of the 0.9mm nickel-silver
wire through the hole in the back of the carrier and across
the top, parallel to the line of the axle. With a small amount of
flux, solder the wire in place, at the same time reinforcing the
folds and butt joints around the top of the carrier. Keep the
bearing clamped in the vice while soldering; this will act as a
heat sink and prevent melting of the joint between the bearing
and carrier.
Bearing Carrier Instructions for Six-wheel Bogies 15/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

We hold the 0.9mm wire in the correct
alignment with the bearing as shown here.
Cla mp the wire horizontally in the 'helping
hands' at a distance above the bench that
allows the hand vice, holding the bearing, also
to rest on the bench. Using one hand to
steady the vice, the other is free to wield the
soldering iron. Snip off the wire, close to the
bearing, when done, and it's ready for the next
one.
Trim the wire and finish it flush to the front and back of the bearing with a file. Clean
off any solder which adheres to the outer faces of the ears. Ensure the holes in the
ears remain clear of solder.
Taking each subframe etch in turn, check that the carrier
assemblies can slide freely in their respective subframe slots (see
the next paragraph for a solution to bearing misalignment). It is as
well at this point to associate each bearing assembly with a slot
according to the markings on the bearing carriers and subframes,
whether or not you have individually matched the bearings with slots.
File away any burrs from the outer edges of the carrier tops. The fit
along the line of the axle, i.e. of the subframe plate between the
bearing flange on one side and the inner facing edges of the carrier on the other, should
be quite loose to accommodate tilting of the axle. Check that all traces of the tag are
removed from the edge of the bottom face of the carrier, as otherwise it can bind with
the lower edge of the subframe slot.
Although the aim is to have the bearing
flange parallel with the front face of the
carrier, a certain amount of misalignment can
be tolerated. If, however, you find that the
subframe side is 'pinched' between the two,
then an individual carrier assembly can be
corrected by clamping the back of the top of
the carrier against a flat working surface. The
soldering iron can then be applied to the
bearing to melt the joint between bearing and
carrier and allow the back of the bearing to be
held down against the same surface. This
should set the correct alignment.
That completes the bearing carrier assemblies. To finish off, clean them up to remove
any flux residues, and put the carriers and subframes safely away in their respective
containers.
Bearing Carrier Instructions for Six-wheel Bogies 16/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

Bachmann Class 66: Subframes
This section describes the construction of the bogie subframes.
On the Mainframe etches (S2), check that
the slots in the sides are clear to take the
etch thickness.
Make the two main longitudinal folds, each
of which is in three parts carried over the
transom sections under each axle slot. Ensure
the folds are at a true right angle.
Remove the spring Seat-Ear etches (S5)
from the fret. There are two of each hand
for each bogie.
Check that the small etched holes are clear
to pass a 0.5mm drill.
Bachmann Class 66: Subframes 17/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

Fold over the small tags at each of the
corners of each Seat-Ear etch.
Make the 180° fold, with the fold slot to
the outside of the fold, at the centre of
each Seat-Ear, to fold the two layers of the
ear back on themselves.
Fold out the lateral restraint ear,…
… and the longitudinal restraint, from each
Seat-Ear.
Bachmann Class 66: Subframes 18/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

Completed Seat/Ear fold-up.
From inside the Mainframe, fit each Seat-
Ear through the slots in the side of the
Mainframe between the axle slots.
Apply flux to the three laminations - etched
holes are provided to facilitate this - and
support them firmly together before soldering
them in. Ensure that the slots and holes for the
springs remain free of solder: use a 0.5mm drill
to clear them if required.
Ensure each of the fold over tags along the
top edges of the Seat-Ears is reinforced
with a small fillet of solder.
Re-check that the main mainframe folds are
at 90°, and then check against a flat surface that the eight secondary suspension
seats are square and level.
Remove the Baseplate (S1) etches from the
fret and make the 90° fold at each end of
each one.
Bachmann Class 66: Subframes 19/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021

Fit the Baseplates to the underside of the
Mainframes (there are two different types,
each of which will fit only the correct aperture)
and solder in place.
Remove the Outer (S7)…
…and Inner (S6) Stretchers from the etch
and make the two folds in each.
Some of the photos show an earlier
version of the Inner Stretchers, without
the two vertical slots.
The frames are not reversible. The 'two-
spot axle' end of each frame is the
outer, i.e. coupling, end.
Engage the top parts of the stretchers in
their slots in the Mainframe sides, support
their lower ends against the Mainframe cross
members, and solder them in place.
Check that the whole assembly is square
and true.
Reinforce each of the Mainframe folds with
a fillet of solder. Take care to ensure that
the region immediately around the axle bearing
slots, for at least about 1mm around the edges
of the slots, is kept free of solder.
Bachmann Class 66: Subframes 20/60
(c) PenBits Model Railways, All Rights Reserved 27/09/2021