Block instruments and bells

[The Stationmaster]

17 hours ago, St Enodoc said:

There's a book called "Railway Signalling and Communications - Installation and Maintenance", a digest of lectures given by various LNER S&T staff and published by The St Margaret's Technical Press. London, in 1940. It includes all sorts of wonderful stuff including a whole chapter on "Telegraphs and Signalling Instruments", which has several schematic diagrams of how block instruments, single line instruments and so on work.

GWR block instruments (both the older disc type) and the 1947 version are very easy to wire and work very nicely on 12v dc, as do the block bells.  Only problem is that you can no longer buy them for 7/6d each. 

[clecklewyke]

Here is some useful information forwarded by Richard Hodgson:
 

,” Mike  Norris said details of his  and Steve Hall's were in MRJ 216, 219 (both 2012) and 220 (2013)”

 

I hope you will find that useful.

 

Ian

 

 

[SHMD]

..hmm. I wonder what I can do with these...

 

 

 

Kev.

 

[t-b-g]

1 hour ago, SHMD said:

..hmm. I wonder what I can do with these...

 

 

 

Kev.

 

 

Maybe something like this.

 

 

[SHMD]

 

..here's the base drawn.

I will try and machine it tomorrow but I will have to program the CNC first.

 

 

Kev.

 

 

 

 

[St Enodoc]

10 hours ago, SHMD said:

..hmm. I wonder what I can do with these...

 

 

 

Kev.

 

Buy a bike?

[t-b-g]

11 hours ago, SHMD said:

 

..here's the base drawn.

I will try and machine it tomorrow but I will have to program the CNC first.

 

 

Kev.

 

 

 

 

 

Very hi tech! The Denny design illustrated above incorporates a feature that has proved to be very useful, in that the mounting arm can be adjusted to move the bell away or towards the "rest" position of the striker. This allows an element of "tuning" in that the bell can be set up to give a lovely clear ring. I would suggest that including some adjustment of the bell or the striker is worth thinking about if you have not already considered it.

[SHMD]

24 minutes ago, t-b-g said:

 

Very hi tech! The Denny design illustrated above incorporates a feature that has proved to be very useful, in that the mounting arm can be adjusted to move the bell away or towards the "rest" position of the striker. This allows an element of "tuning" in that the bell can be set up to give a lovely clear ring. I would suggest that including some adjustment of the bell or the striker is worth thinking about if you have not already considered it.

 

You mean this :-

(I'm still trying to finalising the design - based on the pic on the net.) 

 

 

 

Kev.

 

[SHMD]

5 hours ago, St Enodoc said:

Buy a bike?

 

It would certainly be easier!

 

 

Kev.

 

[t-b-g]

8 minutes ago, SHMD said:

 

You mean this :-

(I'm still trying to finalising the design - based on the pic on the net.) 

 

 

 

Kev.

 

 

I wasn't quite sure what all the bits on the drawing were for, so I thought I should mention it before you start manufacturing!

[St Enodoc]

45 minutes ago, t-b-g said:

 

Very hi tech! The Denny design illustrated above incorporates a feature that has proved to be very useful, in that the mounting arm can be adjusted to move the bell away or towards the "rest" position of the striker. This allows an element of "tuning" in that the bell can be set up to give a lovely clear ring. I would suggest that including some adjustment of the bell or the striker is worth thinking about if you have not already considered it.

Nearly 50 years ago, Ray Hammond showed me how to make a single-strike bell. His method was to bypass the  trembler (is that the right word?) and adjust the striker arm so that when the armature was fully pulled across there was a tiny gap between the striker and the dome. You have to run the bell on straight DC obviously.

[t-b-g]

2 minutes ago, St Enodoc said:

Nearly 50 years ago, Ray Hammond showed me how to make a single-strike bell. His method was to bypass the  trembler (is that the right word?) and adjust the striker arm so that when the armature was fully pulled across there was a tiny gap between the striker and the dome. You have to run the bell on straight DC obviously.

 

I claim no credit! The bell in he photo is pure Denny, including the home made solenoid.

[SHMD]

OK, I've redrawn the base.

(Please ignore the biggest error in that the bell - dashed - should be ovoid in shape!)

 

Now for the tool paths, which will probably throw-up more changes!

 

 

Kev.

 

[The Stationmaster]

3 hours ago, t-b-g said:

 

Very hi tech! The Denny design illustrated above incorporates a feature that has proved to be very useful, in that the mounting arm can be adjusted to move the bell away or towards the "rest" position of the striker. This allows an element of "tuning" in that the bell can be set up to give a lovely clear ring. I would suggest that including some adjustment of the bell or the striker is worth thinking about if you have not already considered it.

A very simple way to alter the note/tone which the bell rings is to 'slug' it - folk used to use chewing gum for that purpose but far more high tech solutions are available nowadays.    Two part epoxy would probably do the job quite well and you put it inside the dome of the bell where it doesn't show - different amounts to change the tone in different ways.  Blutack would work but might not be durable enough?  another way of course is to loosed the retaining nut but that might not remain consistent.

 

Notwithstanding very different official shapes of block bells it was not unknown in my experience to find bells which a Signalman had slugged to make them more distinctive by flattening the note they sounded. 

[Winander]

I may be teaching my grandmother......

 

The striker needs to have some spring so that the hammer strikes the bell and springs back - if it is too stiff or badly adjusted and hits the bell and stays in contact, all you will get is a dull thud. An alternative to making the arm adjustable is to get (or alter) a bell with an off centre fixing hole - turning the bell changes its relationship to the striker and its tone. I believe that's how some original block bells were arranged, making it simple for the signalman to change the tone.

 

[Written before I saw the Stationmaster's contribution]

 

 

Edited April 11, 2020 by Winander

[SHMD]

As these 3 bicycle bells work, I've been driving everyone mad by experimenting with the striker position and adjusting the resonant frequency/damping - not with chewing gum or bluetak (good ideas though) - but with strong button magnets.

Moving the magnets around the dome allows me to hear the result, and once satisfied, can then be glued in place.

 

Another method would/will be to add a nylon or cork/rubber washer to the mounting. Again, simple experimentation will prove suitability.

 

 

Kev.

 

[t-b-g]

It is not so much altering the tone of each bell. There are several  ways of doing that. It is more adjustment to give a good clean strike. If the gap between bell and striker is too small or too big, it just doesn't sound as nice! 

[SHMD]

Toolpaths calculated and simulated - I don't want to waste material OR WORSE break tool bits.

 

The tool has to be shown where each layer (depth) that has to be "carved" out of the solid work piece. Here's the first cut.

 

Some deeper cuts require more than one pass. Here's ALL the tool paths.

..BUT, I will have to change the clamping, and 1 tool, manually half way through.

 

..and voila - the finished (simulated) Base.

 

 

Kev.

(I hope I don't break any tools!)

 

[The Stationmaster]

3 hours ago, t-b-g said:

It is not so much altering the tone of each bell. There are several  ways of doing that. It is more adjustment to give a good clean strike. If the gap between bell and striker is too small or too big, it just doesn't sound as nice! 

You have obviously not heard a GWR 'cow bell' pattern block bell - which just made a rather unpleasant 'clonk' noise when rung.  Incidentally the strker in Western block bells was not sprung but was weighted to drop back to its normal position once the current ceased to pass through the solenoid coils so you got a nice clear note when operated on dc.  (And a lot of very irritating noise from the solenoid coils if the bell circuit was picking up any stray ac interference.)

[t-b-g]

18 minutes ago, The Stationmaster said:

You have obviously not heard a GWR 'cow bell' pattern block bell - which just made a rather unpleasant 'clonk' noise when rung.  Incidentally the strker in Western block bells was not sprung but was weighted to drop back to its normal position once the current ceased to pass through the solenoid coils so you got a nice clear note when operated on dc.  (And a lot of very irritating noise from the solenoid coils if the bell circuit was picking up any stray ac interference.)

 

i used to operate a layout that had block bells for 12 stations along with various junctions. The clever chap who built it had pressed into service just about anything that would make a noise. There were old metal goblets, cycle bells and all sorts. They varied from a nice clear ring to a dull thud! It was there I learned to appreciate the quality of the ring. When we first set the bells up on Buckingham, we got a buzz or a clunk until I realised that the Meccano mounting arm pivoted for a good reason. I have no doubt that bells in real signal boxes made all sorts of noises but I much prefer a lovely musical "ting" any time when operating.

 

I am sure the GCR would never have used the sort of inferior equipment the poor GWR signalmen had to put up with!

[The Stationmaster]

17 hours ago, t-b-g said:

 

i used to operate a layout that had block bells for 12 stations along with various junctions. The clever chap who built it had pressed into service just about anything that would make a noise. There were old metal goblets, cycle bells and all sorts. They varied from a nice clear ring to a dull thud! It was there I learned to appreciate the quality of the ring. When we first set the bells up on Buckingham, we got a buzz or a clunk until I realised that the Meccano mounting arm pivoted for a good reason. I have no doubt that bells in real signal boxes made all sorts of noises but I much prefer a lovely musical "ting" any time when operating.

 

I am sure the GCR would never have used the sort of inferior equipment the poor GWR signalmen had to put up with!

I don't know what sort of block bells the GCR used - maybe a Reading design bought from an outside manufacturer?  But Western block bells are about 1,000 time better than the tinny little things in those BR plastic pig (also known as 'Triang') block instruments bells and also sound far niv cer than LNWR/LMS block bells.  But the NER had some rather nice ones although they were probably from McKenzie & Holland so no doubt designed and manufactured well within GWR territory of course.

 

In my opinion there's nothing to beat the sound of a GWR 'church' pattern block bell, beautiful tone to it and the 'high dome' bell also sounds very nice.

[t-b-g]

38 minutes ago, The Stationmaster said:

I don't know what sort of block bells the GCR used - maybe a Reading design bought from an outside manufacturer?  But Western block bells are about 1,000 time better than the tinny little things in those BR plastic pig (also known as 'Triang') block instruments bells and also sound far niv cer than LNWR/LMS block bells.  But the NER had some rather nice ones although they were probably from McKenzie & Holland so no doubt designed and manufactured well within GWR territory of course.

 

In my opinion there's nothing to beat the sound of a GWR 'church' pattern block bell, beautiful tone to it and the 'high dome' bell also sounds very nice.

 

It was you that said the GWR had some ones that went clonk! As a teenage trainspotter in the 1970s, finding a spot within hearing distance of a proper signal box was a lovely way to spend a summer day. The window would be open and hearing the bells, the clunk of the levers, the swish of the signal wires, all were a big part of the pleasure of the experience.

 

Mr Bound, the GCR signalling chief, was one of the top people in the country and the GCR signalling was well ahead of most. So he would have had the nicest bells!

[The Stationmaster]

7 minutes ago, t-b-g said:

 

It was you that said the GWR had some ones that went clonk! As a teenage trainspotter in the 1970s, finding a spot within hearing distance of a proper signal box was a lovely way to spend a summer day. The window would be open and hearing the bells, the clunk of the levers, the swish of the signal wires, all were a big part of the pleasure of the experience.

 

Mr Bound, the GCR signalling chief, was one of the top people in the country and the GCR signalling was well ahead of most. So he would have had the nicest bells!

Only the cow bell went clonk.

 

And yes, Mr Bound was an excellent and very enterprising signal engineer.

 

[SHMD]

Half a day late and the 1st iteration of the Block Instrument's Base is done.

(..and no broken tools and only a tiny bit of blood!)

 

I'm very pleased but I will revisit the drawing and change the striker adjustment recess and the material thickness.

I will also re do the machining file so that there is less "finishing" to be done to remove the work piece from the bulk material.

 

I will also start drawing the four pillars.

(I'm not sure how my software {or me!} will handle the fourth axis so I might program the CNC code manually for these Pillars.)

 

 

 

 

 

 

Kev.

 

[t-b-g]

21 minutes ago, SHMD said:

Half a day late and the 1st iteration of the Block Instrument's Base is done.

(..and no broken tools and only a tiny bit of blood!)

 

I'm very pleased but I will revisit the drawing and change the striker adjustment recess and the material thickness.

I will also re do the machining file so that there is less "finishing" to be done to remove the work piece from the bulk material.

 

I will also start drawing the four pillars.

(I'm not sure how my software {or me!} will handle the fourth axis so I might program the CNC code manually for these Pillars.)

 

 

 

 

 

 

Kev.

 

 

That looks like the dogs whatsits. You should be careful showing stuff like that on here. You may be getting lots of PMs asking "What are the chances of you doing some for me?".