Comet Models LCP34 User manual

The frame etch contains sideframes, pony truck, coupling rods, brake shoes, brake pull rods and
balance weights to produce a chassis of the correct scale dimensions and appearance which
can be used as a substitute for a kit or RTR chassis.
We recommend our gearbox GB5/20 with a Drive Extender and the Mashima MH1624 motor,
and can supply the first two together with Markits wheels if required. A separate fret of 00
spacers is included, which can be exchanged for EM (LS10) or P4 (LS60) by returning them to
us in a stamped, self-addressed envelope.
As supplied the frames are suitable for the Airfix/Dapol/Hornby model.
Please note that all bends should be made with the half-etch to the inside and reinforced with a
fillet of solder.
Assembly Instructions
1. The frames may be assembled rigid, or with sprung axles using our hornblocks and springs code
LS55. If you wish to spring the chassis cut through the spring hangers using a piercing saw and
remove them together with the centre portion of etch within the hornway. The sides of the hornways
are etched at approximately 5.85mm wide to ensure that any slight variations in the width of the
machined grooves in the hornblocks do not result in any one of them having a loose fit within the
hornway. Each hornway must be carefully dressed with a file to achieve a good sliding fit to each
hornblock, which should then be marked up or placed into a labelled bag to ensure it is assembled
only into the hornway to which it has been precisely matched. Take time and care over this stage,
removing material slowly and from each face equally. The hornblock must drop in freely under
gravity but must not show any fore and aft play which might cause the coupling rods to bind. This
might sound daunting, but the patient builder will be rewarded with a chassis having superior ride,
track holding and traction compared to an unsprung chassis.
2For rigid axle assembly, carefully open out the axle bearing holes in the frames until the bearings are
a close fit, ensuring the bearing flanges fit snugly against the frames. This is best done using a five-
sided broach. If you are using our chassis jigs (see below), DO NOT solder the bearings in place at
this stage. Open out the holes for the brake cross-shafts to 0.75mm.
3. Select the appropriate frame spacers - their size and position will depend on the siting of the body
fixings and your preferred motor/gearbox and pick-up arrangements. A suitable layout of spacers is
shown (sketch 1) when using a Mashima MH1624 motor with a GB5/20 and DE.
4If you are springing the chassis drill out the holes at each side of the hornways and those in the
separate spring etches to 0.5mm as shown in sketch 2. The frame spacers fold to right angles on the
half-etched line. Solder your chosen ones to one of the frames, then assemble by clamping the other
sideframe to the first using wheelsets to check alignment before soldering the second side frame.
This crucial stage of the assembly can be achieved more easily and with greater accuracy by using
our frame assembly jigs (code LS16 for 00, LS17 for EM and LS61 for P4). Full instructions are
provided with them. If you are springing the chassis using our hornblocks please note that you will
need a set of four turnings code LS59 which are intended to locate in the hornway during this stage
of assembly.
5. For a sprung chassis insert the spring and hornblock, ensuring that they are placed into their correct
hornways only. Note that the grooves in the hornblock are not on the centre line. This allows you to
choose a greater or lesser amount of sideplay on each axle. Use 0.45mm wire to locate the spring
detail and solder in place using a minimum of flux. This captures the hornblock and the protruding
centre shackle should ensure that the bottom of the hornblock is slightly above the bottom edge of
the chassis giving approximately 1.0mm of movement only. Do not be tempted to file too much
material from the top of the centre shackle. Greater travel should not be necessary and there is then
a risk that the spring could become dislodged if there is too much downward travel.
6With the frames assembled, solder lengths of 0.7mm wire through the brake hanger holes, then
thread on and solder the brake shoes in place. Their alignment is made easier if something of
suitable thickness is used to space out the brake shoe from the frame, with a wheelset fitted to
ensure correct spacing relative to the wheel treads.
7. Lengths of 0.7mm wire are next threaded through the bottom brake hanger holes on one side of the
chassis, through both sets of pull rods (ensuring they are the correct way round) and then through
the second set of brake hangers. Solder the wire to the brake hangers, then slide the pull rods
outwards to line up with the inner edges of the frames and solder them to the wire. Finally, solder on
fixing nuts for the pick-ups.
8. The coupling rods can be articulated if desired by cutting the full length backing rod as shown in
sketch 3 before soldering on the overlays. Whether you articulate the rods or not, this operation is
simplified if the crankpin holes are first drilled (1.2mm for Markits crankpins) and the backing rod
tinned along its length. Both the backing rod and the overlay can now be threaded onto the drill
which will keep one end in alignment whilst the other is squared up and the rods soldered together
(sketch 4). If using Markits wheels you will need to use a paper washer between the coupling rod and
the crankpin washer to prevent the rods being soldered to the crankpins. These locos had both plain
and fluted rods - check a photo of the one you are modelling to see which you should use. (For plain
rods, use the outer left rods on the right side of the loco, fluting facing the frames, and vice versa.)
9. Open out the bearing hole in the rear trailing truck to suit the wheelset you are using then bend up
the sides and add the vertical plate. The nut can now be soldered to the frame spacer using the
completed truck to gauge for correct positioning.
The chassis can now be washed to remove any flux residues, but before painting we suggest
that you fit the wheels and check the fit of the body. You may find some slight filing is required to
obtain a perfect fit.
Our preference is for wiper pick-ups made from 26swg phosphor bronze wire as per sketch
5.The wire is soldered to PCB strip which is bolted to a frame spacer. We recommend that, if
possible, you arrange the pick-up to be “bolt on” since this allows for easy removal and
adjustment of the wire wipers. Pack LS23 provides all the necessary parts.
Components recommended to construct a
complete chassis:
6 off Markits 5'8" wheels (WH206)
3 axles 6 crankpins and washers (RM2)
1 set Markits 14mm trailing wheels (WH33)
Gearbox GB5/20 and Drive Extender, or GB1/20
Mashima MH1624 motor
LCP34 Chassis pack for
LNER Gresley N2
0-6-2T
Comet Models is part of Wizard Models Limited, PO Box 70, Barton upon Humber DN18 5XY
Tel [phone], web www.wizardmodels.ltd, e-mail [e-mail]
© Wizard Models Limited 2020

SKETCH 3
To split the rods over the centre crankpin cut the backing rod at A-A, solder to the corresponding halves of the
outer rods and connect both halves at the centre crankpin.
To split the rods on the knuckle joint first drill through the half-etched centres on the knuckle and cut the backing
rod at B-B. Solder the inner and outer halves together then join the front and back halves of the rods using a pin
or rivet (not supplied) so that the rods are articulated behind the centre crankpin.
Front half
A
A
Rear half
B
B
Front half
Rear half
SKETCH 1
Option 1 GB5/20 and Extender
Option 2 GB1/20
MH1624
MH1624
Spacer A 10mm x 10mm
Spacer B 10mm x 6mm
Spacer C 6mm x 6mm
Spacer D 6mm x 3mm
DB
BAA
Front fixing Rear fixing
Spacers for pickup busbar
Spacer for trailing
truck pivot
SKETCH 5
Suggested pickup
arrangement
Jointed rods LH or nearside shown
Brake hanger holes
SKETCH 2
Fitting hornblocks
SKETCH 4
Using a drill to aid
coupling rod assembly