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Block instruments and bells


clecklewyke
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  • RMweb Gold

I finally got some wood, of the right size, and found a bit of time from all that working from home rubbish.

(I used to think that if I worked from home I could do all sorts of modelling. Turns out the opposite is true!)

 

Anyway, two cabinets side done in two days!

20200530_151204.jpg.1d3e4254b95cf5fff59d5983d8a69539.jpg

 

20200530_151215.jpg.65a35c24b9b28e01ab2be780ce5bf864.jpg

 

20200530_151240.jpg.8c1a444f8916211f53085fd6ba311ddc.jpg

 

20200530_151841.jpg.acc52a6a35a140c383c5ab4831486298.jpg

 

20200530_152035.jpg.1c99282159b3c9c0fc0c3de65fa5d934.jpg

 

I wonder if Any G (uax6) recognises the pattern of holes?

 

;)

 

 

Kev.

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I spent way too many hours today making just one connector block - and it's not finished yet!

 

20200531_150855.jpg.12454679e3139d9492ccfca9df1485ab.jpg

 

However I am very pleased with it, not only because of the dimensions, but also the proportions look good too.

As a plus It is also very strong, but I will need to Counter-Sink the two free holes and source some SS M2 x 4mm screws.

Then I can mount it the right way up and have it fully populated with the correct number of screws.

 

For this Instrument I'll need to make 14 long block (as shown above) and 2 square blocks.

I'll make them out of Nickel Silver instead of brass though. (I only had brass to hand this morning.)

 

This is just part of, (like every part of this build), a feasibility study for when I make some "good" block Instruments later.

 

 

Kev..

 

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A day of CAD, one and a half days of breaking mills and drills, learning and making scrap - I finally made, (after a further 8 hours of machining!!!), what I wanted.

 

CAD with CNC - just make anything at a press of a button - yeah, right!

 

So, the CAD - easy enough.

image.png.730ac1facfd61a78018c73c00ba4a298.png

 

Then the CAM to specify toolpaths, cutting speeds and depths - a bit of a ball ache!

image.png.763797b530f157a5f9970bbe399fb9e9.png

 

Then the machining - a right ba$£@rd!!!

(Ping goes another bit or the job becomes loose.)

image.png.20d360a6d37b1bd053f98b74b81c302c.png

I finally settled upon (got away with) 0.33mm/s feed, a 0.25mm cut depth, and at 24000rpm!!!

 

The result (on the fifth attempt) - I'm pleased with.

image.png.22eda37d38c8b37510accac26675fcac.png

(The four previous attempts are on the right but I might be able to salvage something from amongst the scrap.)

 

Next, I need to drill out the smaller holes to 1.6mm and then Tap them. The larger holes need to be counter-sunk.

After that, I can cut out the individual blocks and tidy them up before electroplating them with Tin. (Distilled vinegar and pure Tin is already on its way)

(I'll use the scrap pieces to setup on first.)

 

 

Kev.

 

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  • 3 weeks later...

My go at a block instrument. As you will note, my interest is much more in simulating operations (timetabling, shunting, signalling etc) rather than in model making.

My model railway track is 00 gauge, sharing space above my work bench. The track consists of a terminus/ station/ goods yard with a run around loop on the right. On the left is a fiddle yard with 3 tracks. Connecting the two is a short single track line. The engines and most of the stock is GWR, bought some time ago. The ends of the track fold up to save space.

The details of how I have done it - and more importantly the things that haven't worked are in the next post.

IMG_7129.JPG

IMG_7128.JPG

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  • 8 months later...
  • RMweb Gold

@SHMD did you finish building this? I was following with interest as it’s something I’d like to have a go at.

 

@MerlinH can I ask what is the big black box with the red handle that you’re using as the three way switch on the front of your instruments? I can’t see it mentioned in your posts or pdf (sorry if it’s there and I missed it).

 

Great stuff - I’m sure there would be a market for something like this - a better looking version of the old Triang signalling instruments (which now go for silly money), using modern technology.

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This is a very interesting thread. Can't believe I've only just coe across it!

 

A few years ago, I had a go at making a pair of Tokenless instruments, and 3 pairs of block bells.

 

23525089664_87daefff73_c.jpg

24153297975_3ae8205e44_c.jpg

23857654890_e78b0152dd_c.jpg

 

There no where near as nicely engineered as some of the other instruments shown in the thread, but they work. I had a go at a pair of Electric Key Token machines too, but never quite got around to finishing them, and there were plans to make two pairs of GW 43 patern(ish) Absolute Block instruments too. Really must get around to finishing them all.

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4 hours ago, D1037 said:

This is a very interesting thread. Can't believe I've only just coe across it!

 

A few years ago, I had a go at making a pair of Tokenless instruments, and 3 pairs of block bells.

 

23525089664_87daefff73_c.jpg

24153297975_3ae8205e44_c.jpg

23857654890_e78b0152dd_c.jpg

 

There no where near as nicely engineered as some of the other instruments shown in the thread, but they work. I had a go at a pair of Electric Key Token machines too, but never quite got around to finishing them, and there were plans to make two pairs of GW 43 patern(ish) Absolute Block instruments too. Really must get around to finishing them all.

 

@D1037 They look great. Any more details on the internals of the block instruments please?

 

I've just this evening ordered a couple of 3-position switches for the front of my attempt, and already have a solution for the bell and key. Just all the bits in between to sort out!

 

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Before I go too far down a wrong path, would emulating the operation of the Triang block instruments be a good starting point?

 

Are the Triang operating instructions correct? It seems to me that there might be a few steps missing in the settings of the switches on the two boxes?

 

@Pacific231G posted the details and instructions here, earlier in this thread:

 

I have something like this in mind (two identical boxes wired together, switch on one sets the pointer on the other, morse key dings bell on other):

1623849182_block_instrument_fascia-Copy.jpg.22525c1e9224d3124c6228ba000accda.jpg

 

i.e. an exact knock off of Triang's instruments, but using different technology :).

 

 

 

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20 hours ago, GWR57xx said:

Before I go too far down a wrong path, would emulating the operation of the Triang block instruments be a good starting point?

 

Are the Triang operating instructions correct? It seems to me that there might be a few steps missing in the settings of the switches on the two boxes?

 

@Pacific231G posted the details and instructions here, earlier in this thread:

 

I have something like this in mind (two identical boxes wired together, switch on one sets the pointer on the other, morse key dings bell on other):

1623849182_block_instrument_fascia-Copy.jpg.22525c1e9224d3124c6228ba000accda.jpg

 

i.e. an exact knock off of Triang's instruments, but using different technology :).

 

 

 

The main disadvantage of this arrangement (although none too relevant on a model railway) is that you don't know if the indicator is responding to the movement of the switch.  That is of course essential in the real world where the indication on the instruments at each end of a block section have to be in agreement but as far as model is concerned that is a moot point so it could well be thought of as a 'nice to have' rather than essential. 

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I've given it a bit more thought and played around with a few ideas.

Eventually I ended up with a design I think works, so I built this cardboard aided design mockup just to check sizes and spacings:

 

DSC02828.JPG.2d40fa89179abd275ea92807007be2e2.JPG

 

Next step is to build a box for it and order the missing components.

 

Edited by GWR57xx
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On 24/02/2021 at 15:27, GWR57xx said:

Before I go too far down a wrong path, would emulating the operation of the Triang block instruments be a good starting point?

 

Are the Triang operating instructions correct? It seems to me that there might be a few steps missing in the settings of the switches on the two boxes?

 

@Pacific231G posted the details and instructions here, earlier in this thread:

 

I have something like this in mind (two identical boxes wired together, switch on one sets the pointer on the other, morse key dings bell on other):

1623849182_block_instrument_fascia-Copy.jpg.22525c1e9224d3124c6228ba000accda.jpg

 

i.e. an exact knock off of Triang's instruments, but using different technology :).

 

 

 

Apart from not being integrated into the interlocking system of a signalbox, the only operatonal difference between Tri-ang's block instruments and most real ones was the lack of the "local" indicator needle that, as The Stationmaster says, ensures that the state set by the commutator is actually being transmitted. Effectively it is in series with the indicator in the box in rear so if there was, for example, a break in the wire then the circuit would not be completed and both needles would remain at normal/line blocked. (Some earlier block instruments didn't include this feature either)

That doesn't affect theiir operation so they certainly could be used entirely prototypically. 

 

The other main difference, that didn't affect their functionality,  was that the Tri-ang instruments were electrically somewhat simpler but at  the cost of requiring more wires to be run between them, one for each of the two coils moving each needle and one for each bell so six in total plus the two wires connecting each unit to a power supply. 

Most real block instruments seem to have been three wire with one wire for each direction and a third for the bell circuit with the circuits completed by earthing them at each end. To achieve that required that the wire for each indicator could be at a positive, negative or zero voltage so it needed a split potential power source (normally a battery) . I think the bell circuit worked both ways by the tappers making a circuit to ring the bell at the other end when pressed but also breaking the connection to the local bell so pressing your tapper wouldn't make your bell ring. I think this was the standard way for telegraph keys to work in general so that only one wire would be needed to be run between them.

(One oddity of the Tri-ang instruments was that they could run on AC power just as as well as on DC - thus being able to use the AC accessory output of most model railway controllers)

There was a note in Tri-ang's instructions that, apart from being unpowered between operating sessions, the commutators should not be left set to "line clear" or "train on line" for extended periods because of the risk of overheating. Obviously, the coils used- presumably lower powered versions of those used in Tri-ang's point or signal motors- couldn't be kept powered for too long.   

Edited by Pacific231G
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As suggested by David ('Pacific 231G') most traditional block circuits for both the instruments and bells used earth return as it was cheaper and, generally, problem free.  I have know a bell circuit suffer from interference although it didn't make the bells on the crcuit ring properly although it did make them 'tremble.   While a nearby high voltage ac overhead route was suspeced as being the cause it definitely wasn't as the problem comntinued long after the CEGB switching that circuit out (it was never permanently live);  the block circuit wasn't affected.

 

On a model there's no reason why a block circuit can't be interlinked with the working of signals assuming some sort of electric lock or control is/can be used to work the signals.  The  simplest control is a Section Signal being released by 'Line Clear' although a sort of Home Normal control on acceptance could be applied via the lever frame instead of using the signal itself but again depending on how teh signal is operated it could apply the control.

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11 hours ago, The Stationmaster said:

As suggested by David ('Pacific 231G') most traditional block circuits for both the instruments and bells used earth return as it was cheaper and, generally, problem free.  I have know a bell circuit suffer from interference although it didn't make the bells on the crcuit ring properly although it did make them 'tremble.   While a nearby high voltage ac overhead route was suspeced as being the cause it definitely wasn't as the problem comntinued long after the CEGB switching that circuit out (it was never permanently live);  the block circuit wasn't affected.

 

On a model there's no reason why a block circuit can't be interlinked with the working of signals assuming some sort of electric lock or control is/can be used to work the signals.  The  simplest control is a Section Signal being released by 'Line Clear' although a sort of Home Normal control on acceptance could be applied via the lever frame instead of using the signal itself but again depending on how teh signal is operated it could apply the control.

For example:

 

 

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On 21/02/2021 at 08:41, GWR57xx said:

@SHMD did you finish building this? I was following with interest as it’s something I’d like to have a go at.

 

 

 

 

Hi GWR57

 

Sorry it's been a while but I've taken a different tack!

The pictorial record provided by uax6, (thanks again), left me with more questions about dimensions and Construction than would have been polite to keep mithering for.

 

So I bought myself one!

20210307_162601.jpg.0d1a0b450b873fecc9fca0222f1bc519.jpg

This is a much later one than uax6's. This is a J&F version for BR, made in 1958, but it is amazing how similar they are.

 

It's also HUGE !

A tad over 2ft tall and with tons of presence.

(I don't remember these being that big in the boxes I visited!

 

So what about the half finished one I was working on?

Well, pretty much where I left it but doesn't it look tiny next to the real thing?

20210307_162644.jpg.863bdc6b7627380e8ded4ebf80bef6d9.jpg

I though "half scale" would be bigger than that!

 

I will finish it, but not as a Block Instrument. It will be a key cabinet (lower half) and an analogue clock (top half).

 

So progress?

Measuring and drawing mainly.

image.png.b86e64de94c6d93f53aae696c0afc5b1.png

There are a lot more measurements on this, drawing. Much more than the few indicated here would infer.

 

I have stated, on the drawing, that "most measurements are to the nearest 0.5, 1.0 or 2.0mm".

This needs clarifying as it is very important.

A lot of thought has to go into, not just taking the measurement, but in how to interpret it, how it will be applied (to the Drawing), how it will scale, what materials will be available, and finally, how the CAM software will use the dimensions to create the CNC file.

 

With this "General Arrangement" drawing, I have tried to capture the measurements as accurately as I could but rounding up, or down, depending on whether the answer is even or not.

A simple measurement, on the Instrument, may be easy to take but on the CAD I need to apply it from centre-line datums IE halve it.

Then, the detailed individual parts are going to be drawn exactly half scale. Again, I would like these to be nice round numbers.

So, a lot of dimensions are going to be initially halved and the ALL the dimensions are going to be halved again.

 

It's interesting to "realise" the origins of the dimensions and methods used to make it.

11" x 6.5" x 1.5" for the Plinth. Or 2" and 4" standard hinges. etc..

Then there's the fact that there is not a straight edge anywhere! The cabinet is nearly 2mm narrower at the front then the back! It is 624.7 mm high, when measured from the left side, and 623.4, when measured from the right hand side!

Most (wood) cuts were made by hand and are just not straight or consistent - when you look closely.

There are even mistakes - which I just don't want to reproduce.

 

As I say, lots of interpretation.

Having measured this now, a quick look on the Internet, easily shows up that these Instruments are ALL different - especially when comparing the wood carving.

 

It's a good job I like drawing though, there is plenty more to do!!

:)

 

 

Kev.

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  • RMweb Gold

Seeing 'St Enodoc's 'interesting/thoughtful' tick on the above post am I now required to get my GWR block sintrument out to measure them - 1905 version of the Spagnolttri pattern instrument or the 1946 instrument?   The Spagnoletti style ind strument uses moving discs instead of moving needles and it has keys instead of a commutator. (the keys are held down by a wire slide.  The Western used separate block bells which - depending on shape - sounded much nicer than the small bells incorporatedin the LNWR patter and BR 'Triang' pattern instruments.

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  • 4 weeks later...
  • RMweb Premium

Humm, thats a nice block. I wish mine was a double track block and not a single line one.... ;-9....

 

But you are right they are massive, the look smaller on a block shelf though, and I'm not sure why?

 

Andy G

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If you are building your own, I would say choice of the bell tapper is worth thinking about.  Don't forget the bell you are ringing is in the next box, so you can't hear it.   If you are used to sending bell codes on the type of LNWR instrument shown above what you hear is a very audible tap as the morse type key strikes the contact to complete the circuit.  If you use something like a bell push, you won't get the tangible and audible indication of what you are sending, and it just won't feel right if you can't hear what you are sending.

 

Having said that, some other type of instrument use plungers (eg the LYR ones and Tyers tablet instruments) and you don't hear the tap and they feel very different.  In the case of single line instruments, at least you get a galvanometer needle movement confirming the current flowing to the bell at the far end.

 

Not sure if I have explained this very clearly.

 

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  • RMweb Gold

Michael Hodgsoin's point about bell tappers is well illustrated a in the attached video at c,2.10 - 2.30 or so (we'll excuse the subsequent view of the 'Royal Scot' approaching and passing Harrow No.1 'box on the Up Fast as it isn't the only Up train being passed off as a Down train in this film).

 

https://player.bfi.org.uk/free/film/watch-night-mail-1936-online

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