Semaphore Signals - 4mm Scale (Mainly)

[Steve Hewitt]

The Main Stem (just brass tube at present) Trimmers and one Doll assembled:

 

The bracket work will be assembled from 1mm x 1mm brass angle, and is supported on a short length of channel section where it meets the main post or stem.

To locate the channel section closely on the stem I machined the webs of the channel section as shown, using a 3mm End Mill in my miniature Mill/Drill machine.

 

This ensures a good fit, and that the channel section is automatically square to the main stem.

By keeping the channel over length, it is easy to get its position correct, and hold it for soldering:

 

Still over-length, but nearer to the finished size:

 

To ensure the main parts of the bracket are identical, two lengths of angle are soldered together back to back before shaping with saw and files:

 

With the "vee" cuts made and the angles bent, the two parts were separated and fitted as shown.

 

The minor bracket components were added over-length again before cutting back to size.

(By now the second Doll has been fitted).

 

The supports for the wooden staging, complete with stanchions for the handrail are made like this:

from a length of 1 mm x 0.5 mm brass and my favourite Nickelled pins.

 

Added to the trimmers:

 

 

Finally the bearings for the balance arms are made from shaped square brass tube, and fitted to the main stem at the appopriate height:

 

The next stage is the signal's "foundations", but with the discussions about working or fixed arms having started, that is all on hold until I agree the way forward at the Manchester show this weekend.

 

More will follow...

 

Steve.

[Howard Smith]

Hello Steve,

I've only just come across this topic and it's nice to see some "proper modelling". Keep up the good work!

Regards,

Howard

[Jon Fitness]

As always, an excellent bit of engineering as well as a nice bit of modelling. Hope to see it in the flesh at Manchester!

JF

[Steve Hewitt]

As always, an excellent bit of engineering as well as a nice bit of modelling. Hope to see it in the flesh at Manchester!

JF

 

Hi Jon,

 

I'll be a visitor to the show, on Saturday.

When are you going?

We might rendez-vous?

 

Steve.

[Jon Fitness]

Hi Jon,

 

I'll be a visitor to the show, on Saturday.

When are you going?

We might rendez-vous?

 

Steve.

Hi Steve,

Should be there for 1100 and staying till about 1500 (got to get back for 1800 night shift!).

Jon F.

[Horsetan]

This bracket structure reminds me of the retort stands we had in Chemistry lessons at school...

[Steve Hewitt]

A little more to report, having been "at rest" with this project for a couple of weeks or more.

 

The specification for the working elements has now been defined.

Because the left hand doll refers to a route which isn't modelled beyond the immediate pointwork, the arms will be fixed.

The right hand "distant" will also be fixed, as the prototype.

There is only one working arm, the right hand "home".

 

The original intention had been for all four arms to be operational, and the foundations had been made for such as shown here:

First the tube which is turned from brass bar, to ensure the main post is vertical to the base plate:

 

 

The base plate is Nickel Silver, marked out and drilled in the sheet:

 

The hole for the turning is opened up to size using a taper reamer:

The base plate is cut from the sheet with a piercing saw.

 

The flange on the turning is relieved where the guide tubes for the operating wires will pass through:

 

The tube is positioned in the base plate, and soldered with the blow torch:

 

The guide tubes are 1/16in dia brass tube, to give a sliding fit on 1/32in dia tube which in turn will be soldered to the actual operating wires. This is designed to keep the length of the operating wires to a minimum to help avoid any buckling when "pushing".

 

Finally, the 5/8in dia brass tube is fitted. This gives an easy method of installing and securing the signal on the layout, and locating the board on which the servos will be mounted.

 

 

This was how far I'd got when progress was halted.

This base will be retained for use on a suitable Carlisle signal at a later date. The list of signals needed seems to grow like topsy.....

 

 

I've now replaced the above with a similar but simpler foundation for only one operating wire.

 

More soon,

Steve.

[Highlandman]

This is a fascinating and informative thread. They say imitation is the sincerest form of flattery so this is my first attempt at building 4mm signals using some of your methods. The only thing I'm missing is the lathe to turn sockets for the posts to make sure they are square on the base plate.

 

 

 

 

 

If mine turn out half as good as yours Steve, I'll be very happy.

[Steve Hewitt]

This is a fascinating and informative thread. They say imitation is the sincerest form of flattery so this is my first attempt at building 4mm signals using some of your methods. The only thing I'm missing is the lathe to turn sockets for the posts to make sure they are square on the base plate.

 

If mine turn out half as good as yours Steve, I'll be very happy.

 

Thanks for your comments.

I started the topic hoping to encourage others to "Have a go", so I'm pleased that you've taken the plunge.

 

I must say your progress to date looks very encouraging.

I've found your layout topic, so I'll keep an eye on your project from time to time.

 

Steve.

[Steve Hewitt]

The saga continues:

 

Having determined that only two arms on the prototype actually operated, I've reduced the balance lever bearings to one, which will carry one working and one dummy balance lever.

 

The model will have working lamps, using Fibre Optics from a below baseboard light.

The MSE cast lamps are drilled through 0.5mm before fixing to their brackets:

 

 

 

And this is the state of the signal prior to painting:

 

 

More soon....

Steve.

[Highlandman]

The signal is looking good, but I noticed that you leave the balance arms off while you paint it. How do you then attach the balance arm spindles to the painted post so that they stay in place and you do not damage the paint job?

 

[EDIT] Sorry another question. What are the pins you use for the cranks and balance arms? I'm assuming dressmakers pins are to heavy and thick for the job.

Edited October 19, 2012 by Highlandman

[Steve Hewitt]

The signal is looking good, but I noticed that you leave the balance arms off while you paint it. How do you then attach the balance arm spindles to the painted post so that they stay in place and you do not damage the paint job?

 

[EDIT] Sorry another question. What are the pins you use for the cranks and balance arms? I'm assuming dressmakers pins are to heavy and thick for the job.

 

All the moving bits are left off and painted or blackened separately to the main structure.

The blackened balance arms are eventually assembled in their bearing by inserting a shortened lace pin of 0.45mm dia.

The pin is retained with a minute drop of Loctite under the head.

The head is then coloured with a permanent Black Marker.

Pictures will follow when I reach that stage.....

 

The pins used on this model are all the same.

They are the arm pivots, the balance lever pivots and the handrail stanchions.

I buy all my pins from a Lacemakers' supplier. http://myweb.tiscali...ornsby/Home.htm

They are excellent quality products and the firm are very good to deal with.

 

Steve.

[Steve Hewitt]

The saga continues:

 

Having determined that only two arms on the prototype actually operated, I've reduced the balance lever bearings to one, which will carry one working and one dummy balance lever.

 

The model will have working lamps, using Fibre Optics from a below baseboard light.

The MSE cast lamps are drilled through 0.5mm before fixing to their brackets:

 

And this is the state of the signal prior to painting:

 

More soon....

Steve.

 

So, here we are after some painting.

First the fibre optics have been threaded through each lamp, and routed down the signal's structure to disappear inside the main stem.

They re-appear "below ground", where they are teminated in a "plug".

 

This plug is turned from brass bar, but it could just have easily been made from telescoping brass tubes.

Its purpose is to hold the ends of the fibres up close to the LED light souce, which itself is mounted (glued) in a brass tube, and epoxied to a scrap of wood for later mounting. You can make out the 1k ohm resistor hidden in the heat shrink.

 

The LED is a "Gas Light" from Helmsman Electronics. Its colour is better than white for use in signals.

 

The effect on the signal is:

 

I preparation for the operating wires being installed, the Rocking Shaft has been made:

 

And the arms have been painted:

 

Assembling all the bits, and making the arms (in this case only one!) move is the really rewarding part which comes next....

 

Steve.

[Steve Hewitt]

Assembling all the bits, and making the arms (in this case only one!) move is the really rewarding part which comes next....

 

Steve.

 

Here then is the final assembly process.

 

The operating wires are carefully cut to length, with the ends bent to a right angle. (Careful which way the bend goes! I've lost count of how many I've made "wrong handed" over the years.)

I usually start with the connection to the signal arm:

 

In this case the other end of this wire is connected to the Rocking Shaft crank:

 

The wire from the other end of the Rocking Shaft to the Balance Arm is next:

 

 

Final connection will be to the servo motor.

First the wire from the Balance Arm is passed through the Guide Tube in the base plate.

From underneath, this is sleeved with a length of 1/32in brass tube up to ground level:

 

Below ground this is connected to the Servo by a length of 1/16in brass tube, formed to be a fit in the Horn of the Servo:

 

 

Repeat the above for each other arm in turn, and you should have a working signal:

 

Finally here is another of my Low Res videos:

 

 

In this case the Servo Controller is an Embedded Controls unit, which have been used on all the Carlisle signals I've built.

 

Steve.

Edited November 3, 2012 by SteveAtBax

[Captain Kernow]

the fibre optics have been threaded through each lamp, and routed down the signal's structure to disappear inside the main stem.

Steve, brilliant work as usual, but unfortunately one part of the process I was particularly looking forward to seeing was how you did precisely that - namely hide the fibre optic strands between them exiting the whitemetal lamp and disappearing into the signal post or doll? Any chance of a photo or two of what that looks like, please?

 

Many thanks.

[Highlandman]

Steve, brilliant work as usual, but unfortunately one part of the process I was particularly looking forward to seeing was how you did precisely that - namely hide the fibre optic strands between them exiting the whitemetal lamp and disappearing into the signal post or doll? Any chance of a photo or two of what that looks like, please?

 

Many thanks.

 

Ditto here, as I thought you couldn't put to tight a bend in fibre optics to get it from the lamp to the post and out. Pictures would be great, a 'how to' video would be even better.

[Steve Hewitt]

Steve, brilliant work as usual, but unfortunately one part of the process I was particularly looking forward to seeing was how you did precisely that - namely hide the fibre optic strands between them exiting the whitemetal lamp and disappearing into the signal post or doll? Any chance of a photo or two of what that looks like, please?

 

Many thanks.

Ditto here, as I thought you couldn't put to tight a bend in fibre optics to get it from the lamp to the post and out. Pictures would be great, a 'how to' video would be even better.

 

Here are a few photos of the back of the signal which hopefully show how the fibre optics are routed:

 

You can see above how the fibre is bent at almost a right angle as it leaves the rear of the lamp casting.

From there the curves are kept as shallow as possible to minimise light leakage.

 

The fibres are routed along the structure and "tie wrapped" at intervals with fine white cotton thread. The knots are sealed with a tiny spot of cyano and the ends trimmed flush with sharp neddlework shears.

(Also excellent for removing items from brass etches - you can cut right up to the edge of the component and leave almost none of the tag.)

 

Fibre optics work by guiding the light from one end to the other by "total internal reflection".

Light won't leak out so long as the angle at which it strikes the internal surface of the fibre is shallow enough.

When the angle is too acute, some light will pass out of the fibre, and be seen as a feint glow.

Light leakage is also facilitated when the surface of the fibre is damaged by scratching or contamination. At the location of the damage, the angle at which the light strikes the surface becomes too acute for reflection, and it escapes.

 

By bending the fibre sharply where it comes out of the lamp casting, the small light leakage simulates the "back light":

I hope you can just see the yellow glow at the rear of the lamp, to the right of the ladder hoop.

 

Sorry, not enough hands to make a video.

I need all three just to tie the knots!!!

 

Steve.

[Highlandman]

Great pictures Steve and a really useful description of how you route your fibre optics. Love the way you use the bend in to the lamp to make your backlight. Was this originally done by accident or did you know it would create this effect. I look forward to more installments in this masterclass of signal construction.

[Steve Hewitt]

Great pictures Steve and a really useful description of how you route your fibre optics. Love the way you use the bend in to the lamp to make your backlight. Was this originally done by accident or did you know it would create this effect. I look forward to more installments in this masterclass of signal construction.

 

"Learning from experience".

Its only an accident when it goes wrong!

 

Steve.

[micklner]

Excellent

 

Where do you source the lighting equipment from please ?

[Captain Kernow]

Steve - many thanks for the explanation and photos.

[Steve Hewitt]

Excellent

 

Where do you source the lighting equipment from please ?

 

The lamps are MSE white metal castings.

 

The fibre optic is 0.020 in (American!) from All Components.

They have now stopped stocking it because of minimum purchasing quantities.

I have seen it from a different manufacturer on another stand at some show or other, but can't recall which.

Kytes Lites probably worth a try.

 

The LEDs, resisitors etc. are from Helsman Model Rail in Blackpool.

John Holden got them for me, as we use them on Liverpool Lime Street's signals.

 

Steve.

[Highlandman]

I like your solution for fitting a light source to your fibre optic cable. How do you retain the fibres in your plug/socket. Are they glued or crimped. I understand 'superglues' can damage the filaments.

 

What size are the Helmsman LED's that you use?

 

As always your thread is a mine of information for us meer mortals.

 

All the best

 

Andy

[Steve Hewitt]

I like your solution for fitting a light source to your fibre optic cable. How do you retain the fibres in your plug/socket. Are they glued or crimped. I understand 'superglues' can damage the filaments.

 

What size are the Helmsman LED's that you use?

 

As always your thread is a mine of information for us meer mortals.

 

All the best

 

Andy

 

Hi Andy,

I'm glad you find my postings helpful.

 

The fibres are superglued in the socket.

I make the socket a close fit, leave about 10mm or more of the fibres protruding, apply a drop of Loctite superglue and leave to dry.

I then snip off the ends of the fibres with a sharp pair of flush cutting snips.

 

If you get a drop of superglue on the surface of a fibre where its exposed, you do get some light escaping, but it doesn't seem to cause any long term damage as used in this way.

 

The LEDs I use are 3mm dia, and are Araldited into 1/8in I.D. brass tube.

The epoxy makes a good insulator for the LED conductors, preventing shorting through the tube.

 

Steve.

[Steve Hewitt]

My next little project is taking me back to where I first attempted to make models of signals.

 

It all started with my annual visit to the Wigan exhibition where I spotted an interesting display on the Embedded Controls trade stand. They had a small N gauge demonstration layout with some 4mm scale signals all working automatically. I was taken by the very prototypical way in which the signals operated, spending some time to understand the technology on offer.

 

At that time (Mid 1990's) our club - Blackburn & East Lancs MRS - had its newish 00 layout "Oxenholme" in a quite advanced state of construction and ready for display at our own annual exhibition the following year. As was common in those days, signalling had been ignored in the developments so far.

 

In one of those mad moments of enthusiasm, I decided I'd build the signals which the layout so obviously required. I purchased two of the Embedded Controls units, each comprising of a large servo motor and a Semaphore Controller, a copy of Derek Mundy's book on Signal Construction and went home to study our collection of photographs to see what I'd let myself in for.

 

For those who are not familiar with Oxenholme, its the junction on the West Coast main-line where the branch to Kendal and Windermere diverges from the route north. Northbound trains often required pilot engines or bankers for the climb through the now infamous Grayrigg, then after Tebay, the haul up to Shap.

 

We modelled Oxenholme from the road bridge at the southern end of the station to a position well beyond the double track junction of the branch line, on its falling gradient. (The main line is modelled on the level rather than on the prototypical climb). Consequently, all the activities associated with the engine shed were undertaken in the fiddle yard and not seen by the audience.

 

A major extension of the layout is currently underway, with the engine shed and various running loops to the south of the station being modelled. It has now come my term to stop admiring everyone else's work on the layout and do my own bit.

 

The extended scenic section requires three new signals to be built.

The north-bound main line needs a Home Bracket signal adjacent to the engine shed, which controls access to the Main Down Platform and to the diverging routes to the Windermere Platform and the by-pass road behind the station's rear wall:

 

Further from the station there are two signals where the Up Goods Loop re-joins the Up Main. These latter two were controlled in those days from Oxenholme No. 1 box, that with its adjacent over bridge will be the new scenic break on our layout.

 

So now its "finger out" time. The layout has been invited to the Kendal show in January, and I'd like to have the signals installed and working by then, if at all possible.

 

Steve.