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LNWR Miniature Arm Ground Signals


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  • RMweb Gold

For some time now I've been pestering Peter Stephenson of Scale Signal Supply to have a 4mm version of his LNWR Ground Signal fret made.

Yesterday I picked up a sample!

It looks a very fine item with all the detail well reproduced and crisp.

 

I'll be building up a couple of examples in the coming weeks and I'll put the details on this thread.

 

Peter has also produced 4mm versions of his etches for the LMS and the Midland Rly ground signals.

I have a sample of each and they look to be just as well produced.

 

Steve Hewitt.

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  • 4 weeks later...
  • RMweb Gold

For some time now I've been pestering Peter Stephenson of Scale Signal Supply to have a 4mm version of his LNWR Ground Signal fret made.

Yesterday I picked up a sample!

It looks a very fine item with all the detail well reproduced and crisp.

 

Steve Hewitt.

 

I've been away for a couple of weeks, but tonight I made a start on the first ground signal for Liverpool Lime Street.

This is a two arm version to control movements from the turntable road to either platform 10 or 11.

 

For a start I've taken this picture of the etch, with a ruler adjacent to show the size.

post-3984-0-11124000-1306449160_thumb.jpg

 

I'll report on the progress and my techniques as and when I can.

 

Steve.

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  • RMweb Gold

The following pictures show progress yesterday, a total of a couple of hours work so far.

 

In another topic I explained how I beefed up the bearings on balance arms etc. by soldering small washers in strategic locations.

The washers concerned come from this Alan Gibson etch:

post-3984-0-93549800-1306533388_thumb.jpg

The holes in each washer are between 0.35 and 0.40 mm diam.

 

The holes in the etched balance arms are drilled out 0.35mm.

The drill is then mounted vertically by its shank on a small wooden block.

post-3984-0-67525900-1306534096_thumb.jpg

In turn, a washer, the etch and another washer are placed on the drill.

post-3984-0-82433200-1306534132_thumb.jpg

Using plenty of liquid flux and a little solder on a clean iron, the parts are joined.

post-3984-0-97910100-1306534167_thumb.jpg

The solder is used to tin all the balance arm, as this will give it a little extra strength, and make adding white metal weights at a later stage much easier.

post-3984-0-63273300-1306534473_thumb.jpg

Result is a balance arm which has a chance of working when eventually mounted on a pivot.

The drill is easily removed from the soldered assembly as being High Speed Steel, solder doesn't take to it very well.

 

Moving on to the tiny signal arms:

Each arm consists of two etches.

There is a full thickness profile to which is attached the arm's shaft.

post-3984-0-12104700-1306533823_thumb.jpg

The shaft is a short length of 0.3mm Nickel Silver straight wire.

post-3984-0-80883200-1306533884_thumb.jpg

In front of this is soldered the half etched detail which gives the distinctive profile of the beading around the arm edge and the spectacles.

post-3984-0-63731200-1306533918_thumb.jpg

These are the two completed arms.

post-3984-0-52693700-1306533954_thumb.jpg

They just require the spectacles to be fretted out with a piercing saw, so that working lenses can be added later.

 

The main body of the signal comprises the two lamp housings, through which the signal arms are pivotted.

This is a simple fold up etch, with the joins soldered and the bends re-inforced.

post-3984-0-32004100-1306534061_thumb.jpg

The bottom cover for the lamp housings hasn't been folded up as I have yet to determine how it will be lit.

I can get a "grain of rice" bulb inside, so that might be the solution....we'll have to wait and see.

 

A trial assembly of the arms on the lamp housings:

post-3984-0-19509300-1306533990_thumb.jpg

 

So the result of an evenings work:

post-3984-0-78833800-1306534510_thumb.jpg

 

This leaves the following part of the etch, comprising the "cast" frame to support the lamp housings etc. and the back blinders for each arm shaft.

post-3984-0-15918300-1306536433_thumb.jpg

This has taken a second evening to post this topic.

Its taking as long to write about as it is to do!

 

Steve.

 

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  • RMweb Gold

Another step or two......

Today I made the two back blinders which will be used to drive the signal arm shafts.

As with the balance arms, I've beefed up the shaft locations and the holes where the operating wire will go.

post-3984-0-88377000-1306621684_thumb.jpg

These etched washers are extremely useful!

 

Next job was to fold up and solder the "cast" base of the signal.

post-3984-0-67163400-1306621754_thumb.jpg

This has had the two holes for the balance arm pivot drilled out, again to 0.35mm dia.

I assembled the arms on a short wire pivot to check all fitted.

Subsequently, I altered the arrangement of the washers to ensure the balance arms have enough separation to allow the operating wires to be fitted without interfering with each other (I hope).

 

Final job today was to confirm that a grain of rice bulb will fit in the lamp housings, with enough room for the signal arm shafts to pass. They do, so I removed the wires from the bulb and replaced them with some varnish insulated wire of only half the diameter of the PVC insulated originals.

post-3984-0-95186900-1306621789_thumb.jpg

This will be much easier to hide when the signal is finally assembled.

 

 

More to follow............

 

Steve.

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  • RMweb Gold

Another small step or two.....

First job was to make the base plate for the model from a piece of Nickel Silver.

Assembled on this were the signal's "cast" base and this was topped with the two lamp housings.post-3984-0-38768000-1306789311_thumb.jpg

The tubes to guide the operating wires were fitted next, in line with the balance weights.

These tubes are quite vulnerable to damage, so they were re-inforced with a piece of scrap etch.

post-3984-0-87481400-1306789500_thumb.jpg

Those who've followed my other topics on signal construction will be aware that I believe in strong engineering of the "working parts". Some would say "over-engineered".

The tiny size of this signal requires that the operating wires are of minimum diameter, in this case 0.3mm Nickel Silver.

To ensure adequate strength, the wires will be reinforced with a sleeve of fine brass tubing from ground level downwards. This helps to prevent any buckling.

A new range of fine brass tubing has recently come to the market, from Albion Alloys.

This photo shows their range in the 1 mm down sizes.

post-3984-0-31508400-1306789727_thumb.jpg

The larget tube is 1mm OD, successive tubes are 0.8mm, 0.6mm, 0.4mm with a 0.2mm dia. wire in the centre.

 

For this signal I will sleeve the operating wire with 0.6mm OD tube.

Consequently the guide tubes shown above are 0.8mm dia.

 

The lamp was fitted next.

The eagle eyed will notice it isn't the one shown previously with the finer wires attached.

That was a casualty of my clumsiness. (As were two more).

Having decided I had failed to allow enough room to squeeze the lamp into the housings, I had to drill another access hole through the bottom of the base.

This time I got it right...

post-3984-0-81283600-1306789764_thumb.jpg

Next I made a first fit of the balance arms to ensure they have enough movement - they have.

post-3984-0-29438300-1306789839_thumb.jpg

Finally I couldn't resist fitting the arms again, even though I haven't yet plucked up courage to fret out the spectacles!

post-3984-0-49926800-1306789977_thumb.jpg

 

That's all for now.

Busy day tomorrow, helping John bring the layout home from storage where its been for several months!

 

Steve.

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  • RMweb Gold

Quite superb, and your description of the steps is methodical and easy to follow. As for calling yourself clumsy for breaking a bulb or two - no-one who is clumsy could have got within a mile of your result here. Terribly impressed!

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  • RMweb Gold

Very nice Steve, reminds me of the pair I decommissioned at West Kirby when I asked if I could have an arm, and I was told - sure, provided you move it back to the car park, so off I went with a trolley ;)

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Steve,

 

Superb work, as the others have said. I'm glad to see someone else using (abusing) drill shanks as a soldering alignment tool! By "fretting out" the spectacles, I'm not sure if you mean to use a piercing saw or drill out to the biggeest size and then filing - the latter might be easier, although either way will be a delicate, fiddly job.

 

Hopefully, the non-illuminated, single arm, versions will prove somewhat easier to build!

 

Regards,

 

Dave.

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  • RMweb Gold

Continued.....

 

First "Thank You" for the kind comments.

I tried to respond to the three of you with a "Multi Quote" reply, but it doesn't work with Internet Explorer9!

 

Yesterday we brought John's layout home from storage, where its been since the end of last year.

It's been out of sight and touch for too long, but I'll let someone else tell you why. It has been worth it!

 

We were now able to check the precise location for this signal to ensure no "underground obstructions" were going to complicate the installation.

We also checked the baseboard thickness at 15mm.

 

First task was to make and fit the location tube to the signal's base plate. (25mm length of 5/16th dia brass tube)

This ensures secure and accurate installation, though a single hole.

post-3984-0-59652700-1306956579_thumb.jpg

The view from below shows the where the tube will eventually locate a sub-board which will carry the two servo motors to drive the signal arms.

Assembling the signal on the mock baseboard allows it to be transferred from the workshop to the layout with a minimum of fitting or adjusting.

post-3984-0-81721300-1306956524_thumb.jpg

 

Next to the arm spactacles.

 

I first drilled each aperture 0.8mm to remove most of the material.

 

I then used my "Instrument Vice" to hold each arm securely. This was given to me by a friend who used to be a gunsmith.

It is very useful and versatile for holding small components in any position you might require.

post-3984-0-06626000-1306956371_thumb.jpg

 

This enabled me to use the piercing saw to fret out the remaining material.

post-3984-0-06900500-1306956396_thumb.jpg

 

Work in progress:

post-3984-0-57181000-1306956327_thumb.jpg

post-3984-0-43191300-1306956349_thumb.jpg

 

The result:

post-3984-0-37232200-1306956417_thumb.jpg

 

Another trial assembly:

post-3984-0-22112100-1306956460_thumb.jpg

post-3984-0-56516500-1306956481_thumb.jpg

 

I suppose the next step will involve the operating wire....

 

Steve.

 

 

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  • 1 month later...
  • RMweb Gold

Continued.....

I suppose the next step will involve the operating wire....

 

Steve.

 

 

Yes indeed!

 

First apologies for the quiet week or five.

We've just been away in the caravan.

 

Operating wires:

On the prototype, the wire from the signal box is routed to the rear of the signal and pulls on an extension of the Balance arm. The connection between the Balance arm with the Blinder/Crank, is a rod behind the lamp casing,

pushing upwards on the Crank. The arm shaft to which the Crank is fixed rotates and with it the signal arm.

 

 

On the model, the operating wire will push upwards from below ground to move the balance arm.

 

The operating wires are/will be blackened 0.3mm N/S.

These will come up from the servos below ground, pass through the balance arms and continue up to the blinder/crank where they are terminated. This means the balance arm is just a passenger on the operating wire, which apart from a few bends, drives the crank directly.

 

I hope the following pictures will make this clear:

 

post-3984-0-71968200-1310591747_thumb.jpg

This side shot shows the use of dummy pivot shafts, on which are mounted the blinder/cranks and the balance weights.

It also shows the nearest operating wire coming up and through the balance arm.

 

post-3984-0-23424500-1310591769_thumb.jpg

 

This second shot shows more clearly how the operating wire continues up to the crank, where it will eventually be terminated (on final assembly).

 

post-3984-0-79684200-1310591790_thumb.jpg

 

This rear shot shows the routing of the wire quite well.

 

post-3984-0-06120100-1310591813_thumb.jpg

 

This, and the shot below complete the tour of this tiny model, which is just 13mm tall.

 

post-3984-0-74211500-1310591834_thumb.jpg

 

Next it will all be dismantled for painting before final assembly of the signal.

Then come the servos and their installation below ground and connection to a power supply for the lamp.

 

Steve.

 

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  • RMweb Gold

Thanks for the pics Mike.

Can you tell me where they were taken please.

 

Steve.

 

The signal is a preserved example at Lord McAlpine's private railway near Henley-On-Thames - not an esay place to get into I'm afraid unles you go with a club or society (2 year waiting list for them I think).

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  • RMweb Gold

The signal is a preserved example at Lord McAlpine's private railway near Henley-On-Thames - not an esay place to get into I'm afraid unles you go with a club or society (2 year waiting list for them I think).

 

Thanks Mike.

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  • RMweb Gold

There's (or was) one on the Bala Lake Railway at Llanuwchllyn, there's also one in my back yard, although somewhat tatty now, and only the lamp + arm part.

 

Thanks Das, we have a similar one in our Club's memorabilia.

 

post-3984-0-64677300-1310749782_thumb.jpg

 

Steve.

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  • RMweb Gold

 

 

Next it will all be dismantled for painting before final assembly of the signal.

Then come the servos and their installation below ground and connection to a power supply for the lamp.

 

Steve.

 

 

 

Here we are, back from the paint shop.

I couldn't resist putting the arms in place and powering up the lamp...

 

post-3984-0-81911300-1311262986_thumb.jpg

 

post-3984-0-95721300-1311262466_thumb.jpg

 

post-3984-0-42040800-1311262508_thumb.jpg

 

There is a little light leakage from the base of the lamp, which I'll hide with a dab of paint.

The lenses are "transparent glass paint" from the local Craft Shop.

Applied with a sharp cocktail stick, to form a thin film which dries in about 24 hrs.

 

More as soon as I can...

 

Steve.

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  • RMweb Gold

 

The "above ground" work has now been completed.

The signal is assembled and the operating wires are installed.

It remains to install the servo motors, on their little sub-board.

When that's done I'll post some little video shots of the operation.

 

In the meantime, here are a couple of photos of the completed signal, with a ruler or thumb to show the actual size.

 

post-3984-0-20614600-1311679815_thumb.jpg post-3984-0-88329700-1311679794_thumb.jpg

 

Unfortunately, the black colour is making it very difficult to show the details clearly.

I'll try to arrange some daylight shots for the video.

 

Steve.

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