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Manufactured by Scale Signal Supply 135 Green Meadows, Westhoughton, BOLTON BL5 2BW. 01942 817 350 |
| Built by Raymond Walley © Raymond Walley - All rights reserved |
Contact me here.
While visiting Guildex some years ago, I was intrigued by the example of a
working lever frame on the Scale Signal Supply's stand. My aim is to run my
railway (still unbuilt of course) as close to prototype as possible and this
means using real interlocking combined with infrared control of battery operated
locomotives. So at the Reading show I ordered a 9 lever frame to experiment with
and test out my ideas.
John Matthews (now Peter Stephenson 2003) of Scale Signal Supply (usual disclaimer) makes it abundantly
clear that there is a good deal of work involved but, since most of the
construction uses nuts and bolts, much of this is in cleaning up and polishing
the castings.
The parts arrived some weeks later and consisted of a large number of lost wax
castings in nickel silver and brass, some 16th brass angle, sundry nuts, bolts
and rivets and a 1 inch square timber baulk. The kit represents a 1 inch to the
foot Stevens "Glasgow" lever frame. The parts are well cast with little flash.
The parts are quite soft so some care is needed until they have become work
hardened.
I began by sawing all the various parts from the sprues with a piercing saw,
separating them into different piles and then sorting out all the parts for each
lever. The frame castings require some cleaning but the job was not onerous and
the basic side frames were soon mounted on the timber baulk that is supplied.
However, it is, as the instructions state, important that this is assembled
square and accurately. It is worth taking time over. I chose not to mount this
on a wooden base at this stage - though the instructions recommend it - but
mounted it in a vice.
At this point one has the choice of cleaning up all the parts and then putting
it all together or to do the job lever by lever. I chose to take the lever by
lever route as it seemed less prone to be boring and would provide motivation as
the number of levers increased.
There is great deal of information in the instructions but it is still a good
idea to get the standard books on mechanical signalling by H. Raynar Wilson
since he provides so much background data.
The first photo shows the various parts required for one lever and tappet bar
after they had been cleaned up. The most
delicate item is the lift rod. For this it is useful to make a jig by drilling a
small hole 48mm from the edge of a piece of ply and gently open it up to accept
the short right angled end. This will allow of accurate filing without risking
bending or breaking the part. Another hole drilled to accept a small nail that
is a close fit in the hole at the other end will help to hold it firm while
filing the sides. The fourth side is more difficult but can be completed with
care.
The lever is made up of two parts. The upper is nickel silver while the lower
part is brass. The upper part needs careful cleaning up and the handle should be
burnished. I used a 2 cut file to shape the rounded top to the handle. This is a
little fiddly since this is also where the casting sprue was attached though
there probably is no other way of casting them. Then a 4 cut file for finishing
followed with wet and dry to get a really burnished finish, like those I
remember from days long ago working in Stetchford box as a booking boy.
It is a good idea I think at this stage to open out the holes to correct size in
all the parts (except the brass angle where the floor plates go) and deepen the
countersink in the floor plates until the bolt head is fractionally lower than the surface.
The instructions are clear on what is which. I also tapped all 6 holes in the
end of the operating arm 10BA so that operating angle irons can be screwed
directly into them.
The catch handles also need careful cleaning up. I found that the slot in them
fitted well over an old needle file with some paper packing to protect the inner
surface. Fitted thus in the vice made filing and polishing much easier on the
pinkies and quicker too.
The latch block is perhaps the most difficult since it is not easy to set it up
in the vice to file up. It required in some cases considerable filing and
appears to be the part that is most prone to distortion during casting. It is
however, essential that it slides very easily on the lever. Important too to
remember that the block must continue to move easily once the lever has been
painted.
The lift arm is soldered inside this and the short angle at the base trimmed to
size. I used 180 degree solder wire and a resistance soldering unit (RSU) with
flux paste (but would now use Carr's 179 degree non-acid solder cream instead).
The arm will need to be held tight in place with a small wooden peg that is a
force fit in the slot. By applying solder from the bottom end it is easy to
watch for the first trace appearing at the other and avoid having much to clean
up afterwards. It may need some solder filing out of the slot to get it to slide
easily on the lever.
Then it is time to do a trial fitting of the parts to test that the block falls
under its own weight. I found that if the catch handle was first riveted to the
lever and checked for free movement before the lift rod was riveted in place,
the process was less prone to seizing up. The first lever had to have the rivets
removed and replaced before it worked well. Make sure that the lift lever is
dead straight.
I soft soldered the two parts of the lever together, again with 180 degree
solder and the RSU and found it adequate but you may prefer to use silver
solder. The parts have locating lugs and holes that are quite accurately
registered.
Photo 3 shows a completed lever, including the tappet bar. I tapped one side of
the slotted fitting in the tappet 10BA and bolted them in place so that they can
be fitted and removed when the levers are in situ. This will make producing the
interlocking less time consuming. Each lever needs the fulcrum polishing to
exact size in the frame so it is advisable to number them to ensure they always
go back in the same place.
Photo 4 shows all the parts ready for assembly and also the embryo locking tray,
which has four locking channels. It is constructed from 1/16th brass angle
tapped 10BA and bolted from underneath through more brass angle and then filed
flush. I got it from Reeves of Birmingham but Eileen's Emporium will probably be
able to supply the brass angle by now as he did
the brass strip for the locking
bars.
Once the levers are built assembly is quick and relatively simple. I chose to
tap the support angle bars on top of the frame to take 10BA bolts to secure the
floor plates, but drilled and tapped them one hole at a time to ensure accuracy.
The first one on the left of No: 1 lever is critical to get right since the
remainder simply butt up to one another.
The last picture shows the completed frame
awaiting completion. Finishing the locking and painting, will not be possible
until I finalise the exact layout for the
experimental track work, turnouts,
signals and locking bars. If the Editor permits then I shall be happy to
describe the building of the locking trays and track in a later article.
These are excellent parts that build into a satisfyingly real piece of hardware from the era of block signalling;
though the process does demand a good deal of hard work and patience. Time taken
averages out to about 3.5 hours per lever so, around 32 hours. However, I used
only hand tools and think that a small power drill would speed things up
considerably probably to under three hours per lever. I plan to get mechanised
before beginning the 30+ levers needed for the layout.
The next job is to get the locking and operation of both turnouts and signals to
work using only mechanical means above the baseboard, just like the real thing!