Great Central Models Robinson GCR Class 8B Atlantic LNER C4 Скачать руководство пользователя страница 16

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Page 16 GCR Class 8B

Caveat

It will look nice if you fit the buffers next but it will be wrong
because it may inhibit the ease with which the parts of the
cylinders can be fitted such as when holes need to be reamed
out slightly etc

Cylinders

Note

The Cylinder Spacers (7,8) have a number of guide holes in
them. The inner pair are for the valve guide rod tubing. Just
outside of these are two 0.3 mm holes which can be used as
guides for locating the spacers accurately across the frames
(use the inner pair of these for EM and the outer for P4). There
are also two 0.45 mm holes each end which are used to locate
the Cylinder Heads (52-55). The two rectangular holes locate
the slide bars.

You may wish to consider using the Markits Double Slide bar
and Crosshead (M4CRHDSns) instead of the supplied cross head.

Drill out the 0.3 mm and 0.45 mm holes. Drill the larger, central, holes for the valve rod to 1.6 mm minimum, for an easier fit of
the working valve gear this should be 1.8 mm. Drill or ream the large outer holes to 2.4 mm if you intend to use a tube down the
centre of the cylinders or 2.1 mm for the Markits crosshead. You may choose to drill out the valve rod holes to 2.4 mm as well
and fit 2.4 mm tubing.

Remove

Cylinder Spacers (7,8)

from the fret and fix into the correct position using 0.3 mm brass wire as a guide, the outer holes

are for P4 and the inner holes are for EM. The cylinder tubes fit in the central end holes with the two rectangular holes used to
locate the slide bars.

Drilling Note

When drilling out the cylinder heads it may help to stabilise them if you solder temporarily a length of 0.9 mm brass wire across
one side since drilling them to 2.4 mm will put quite a strain on the tag holding them into the etch. An easier way to drill out
these 2.4 mm holes may be to temporarily solder the part to a bit of scrap and then drill, then un-soldering and fitting as normal.

Drill the two small holes in Cylinder Heads (49-52) to 0.45 mm. Drill the large centre hole to 2.4 mm or for the Markits crosshead
2.1 mm. Remove

Cylinder Heads (49-52)

from the fret and solder securely in place on the front of the front cylinder support

and the rear of the rear cylinder support using 0.45 mm brass wire to align them.

For the supplied crossheads, fit a length of 3/32” x 1/16” brass tube (2.4 mm x 1.6 mm) so that it is just proud at the front and is
2 mm proud at the rear, 14 mm in total. At the front this fits into the Drwg. 212 Cylinder Front. The front cylinder cover will have
a 1.6 mm tail rod (or the cut down version later) which will help to locate it into the cylinder block.

Slot short lengths of 1.6 mm rod through the inside holes of the Cylinder Spacers (7,8) so that it also runs through the Valve
Guide Spacer (19). Then slot a short length of 2.4 mm tube into the Valve Guide Spacer (19) so that at the rear there is 2 mm
showing and about 4 mm at the front. This will align the rods to the valve chest if fitted along with the Stephenson’s Valve Gear
and simulates the bearing and oiler on the full size locomotive. Solder this in place and remove the 1.6 mm rod.

Slide Bars

Note

Alternatively, the slide bars may be made up from 1 mm x 1 mm nickel silver bar, soldering one part on the top of the other and
filing to shape or using 2 mm x 1 mm bar and again filing to shape

Parts 125-140 form Qty 4 identical slide bars. These are built up in four layers and soldered together with the aid of 0.3 mm brass
wires to locate and secure the individual layers. These are then filed to the correct shape.

Note that the short layer at the top is positioned the correct way around!

Remove

Slide Bar Left Upper Main (125)

(long),

Slide Bar Overlay (127)

(long with half etch section),

Slide Bar Overlay (128)

(medium) and

Slide Bar Overlay (129)

(short) from the etch. Locate using 0.3 mm brass rod and solder up well using high

melting point solder with Nealetin as the flux - or similar.

5.Cylinders and Slide Bars