Mk2 Lever frame musings

Discussions of the prototypes and how to model them. Show us how you do it.
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Colin Parks
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Re: Mk2 Lever frame musings

Postby Colin Parks » Mon Oct 15, 2018 12:50 pm

Dave,

Thanks for finding the information on lever numbers. Even knowing they were on the DCC Concepts website, it took me a while to find them!

Howard,

Love the picture of production line painting! I shall follow your method, but use an airbrush rather than spray cans to apply the paint, which I was thinking would be better gloss rather than matt. On the subject of paint: are there standard colours for levers i.e. signal red and signal yellow. And what about the shade of blue used for locking levers? In your picture, it looks like LNER Garter Blue.

Colin


JFS
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Re: Mk2 Lever frame musings

Postby JFS » Mon Oct 15, 2018 8:22 pm

Colin Parks wrote:Dave,

I shall follow your method, but use an airbrush rather than spray cans to apply the paint, which I was thinking would be better gloss rather than matt. On the subject of paint: are there standard colours for levers i.e. signal red and signal yellow. And what about the shade of blue used for locking levers? In your picture, it looks like LNER Garter Blue.

Colin


Hello Colin

When you have 70 to do - even in a few colours - the spray can blast makes for a quick job not least because the paint is very quick drying. Decanting an aerosol into an air brush usually ends in tears for me! They are indeed gloss paints. Not sure there were standard colours - I just used Wilko's standards! On reflection, my blue might be a bit dark - in the gloom of Leeds City Junction it can be hard to pick out from black. Luckily, there is only one blue lever - all the other blue is on blue/black or blue/brown split combinations. Not being an LNER fan, I would say that a colour around Royal Blue would be about right. One thing is for sure - a nice paint job turns it from looking impressive to looking spectacular!

If anyone is concerned to get the colours "right", there are quite a few decent videos of signal boxes on youtube - here is Exeter West... https://www.youtube.com/watch?v=Tzfs6k68Hvk

One thing no one has asked about is the half red - half green lever. This is "stop shunt" signal - ie it is a shunt signal which is normally "off" to allow shunting, but when the lever is pulled, shunting is stopped. I don't know what colour these should be, so I used red/green. No doubt I am about to find out what it should have been...

Very Best Wishes,

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Colin Parks
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Re: Mk2 Lever frame musings

Postby Colin Parks » Mon Oct 15, 2018 9:39 pm

Ah, perhaps I should consider acrylic spray can colours rather than enamels.

I did watch the youtube video of the Exeter West simulation. That signalman was treating the frame much more gently than the guy testing this frame's mechanical locking: https://www.youtube.com/watch?v=Vw5dcI01kNo

Presumably, the levers were not connected to signals or track at the time.

Colin

Alan Turner
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Re: Mk2 Lever frame musings

Postby Alan Turner » Tue Oct 16, 2018 2:42 pm

JFS wrote:
Colin Parks wrote:Dave,

I shall follow your method, but use an airbrush rather than spray cans to apply the paint, which I was thinking would be better gloss rather than matt. On the subject of paint: are there standard colours for levers i.e. signal red and signal yellow. And what about the shade of blue used for locking levers? In your picture, it looks like LNER Garter Blue.

Colin


Not being an LNER fan, I would say that a colour around Royal Blue would be about right. One thing is for sure - a nice paint job turns it from looking impressive to looking spectacular!


That seems too dark a Blue; certainly all the frames I have worked the FPL is nearer an Air Force blue.

regards

Alan

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grovenor-2685
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Re: Mk2 Lever frame musings

Postby grovenor-2685 » Tue Oct 16, 2018 10:01 pm

One thing no one has asked about is the half red - half green lever. This is "stop shunt" signal - ie it is a shunt signal which is normally "off" to allow shunting, but when the lever is pulled, shunting is stopped. I don't know what colour these should be, so I used red/green. No doubt I am about to find out what it should have been...

I don't recollect ever seeing a colour spec for this sort of lever, I suspect it would just be red, but then there were always exceptions and some Signal Engiineer may have thought they should have a different paint job from other signals.
Rgds

JFS
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Re: Mk2 Lever frame musings

Postby JFS » Wed Oct 17, 2018 8:26 pm

Colin Parks wrote:Ah, perhaps I should consider acrylic spray can colours rather than enamels.


Ah - yes - should have said that! not only do they dry very quickly, but the result is pretty tough!

The frame on my layout was done with enamels and after a few years it is starting to look a bit tatty...

Very Best Wishes,

JFS
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Re: Mk2 Lever frame musings

Postby JFS » Tue Oct 30, 2018 4:31 pm

Just to mention that, further to the discussion above about rolling the quadrant, I have posted a quick Youtube video here:-

https://www.scalefour.org/forum/viewtopic.php?f=4&t=6100

Hope it shows that it is really not at all difficult! In the video, I am using a bit of 6mm foam (actually Exactoscale track underlay) and a Railway Modeller, but anything of similar resilience will do. As a "roller" I am using a peice of 40mm plastic water pipe though anything similar would work. You soon get used to how much pressure is needed to get the right result, but the rule is that if your "Roller" is larger in diameter you will need more pressure and vice versa. If your first attempt results in too large a radius, just re-roll it with a bit more weight.

Hope that helps.

Best Wishes,

Howard

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Colin Parks
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Re: Mk2 Lever frame musings

Postby Colin Parks » Tue Oct 30, 2018 8:27 pm

After an enforced spell of non-modelling, I have started work on the locking frame components, starting with the tappets.

It is all going well so far. I have opted to go for the third method of assembly of the tappets, with the etched port marks on the inside. Some care was needed to ensure that the two halves of the tappet lined up accurately. This was achieved by gripping the tappet edge-on in a vice to line up the edges before soldering. A final squeeze of the tappet halves near the folded-over tabs ensured a tight joint.

The instructions mention opening out the three holes to 0.8 mm, but the tappets have four holes, three at the top and one at the bottom - apart from one half of the 'long' tappet which has no hole at the bottom. So, do all the holes have to be opened out to 0.8 mm? Perhaps the answer will become apparent at the next stage. Still fourteen more short tappets to solder yet though.

At this stage, I still have not finalised the locking chart, so there will be no filing of ports just yet. Assembly up to page 12 looks fairly easy...

JFS
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Re: Mk2 Lever frame musings

Postby JFS » Tue Oct 30, 2018 8:54 pm

Colin Parks wrote: ...

The instructions mention opening out the three holes to 0.8 mm, but the tappets have four holes, three at the top and one at the bottom - apart from one half of the 'long' tappet which has no hole at the bottom. So, do all the holes have to be opened out to 0.8 mm? ...


Hello Colin,

Good to see you back again.

I have to fess up and say that the hole at the bottom was a late addition after the "instructions" had been written. You will not miss it if you had not opened it out!

Its' purpose is to allow you to test the locking without having it fully assembled: a short length of .8mm wire inserted in this hole will limit the upwards movement of the tappet to restrict it to the "Normal" position. The hole at the top similarly limits the downward movement to the Reversed position. Thus, you can try the locking on that one tappet even if the crosshead is not fitted (or not connected up). In truth, it would only be of use if you were building a "long" frame. I have made note to myself to add this info to the destructions.

Best Wishes,

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Colin Parks
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Re: Mk2 Lever frame musings

Postby Colin Parks » Tue Oct 30, 2018 10:47 pm

Thanks Howard. Having only a 20-lever frame to assemble, that is one less hole to worry about then!

Colin

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Colin Parks
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Re: Mk2 Lever frame musings

Postby Colin Parks » Wed Oct 31, 2018 6:19 pm

OK, perhaps this should be under the title 'Locking Frame Musings' but I have a query about tappets.

I have now mass-produced all the tappets, sweating the two halves of each tappet together with no problems. Following the Locking Frame instructions on making the tappets on pages 9 and 10, the instructions state that the etched cusps are to be removed from the port edges until the: 'full thickness of the metal can be seen along the extent of the edges of the port'. I have done this with one long tappet and it is a very sloppy fit in the tray slots, with the finished tappet being something like at least 0.6 mm narrower than the slots. Indeed, the tappets in their 'raw' state complete with etched cusps are still a loose fit in the tray slots.

So, am I missing something here or is this how the tappets are meant to be?!

JFS
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Re: Mk2 Lever frame musings

Postby JFS » Wed Oct 31, 2018 8:54 pm

Colin Parks wrote:OK, perhaps this should be under the title 'Locking Frame Musings' but I have a query about tappets.

... am I missing something here or is this how the tappets are meant to be?!


Hello Colin,

I just had a look at some of mine and that degree of "slop" would certainly work alright, but equally, it is clear that I have not fully followed my own instructions as many of them have quite a bit less slop than that - but there is (and should be) a bit of sideways float to allow a tolerance in the sizing of the nibs which are quite tricky to get "perfect" and so need a bit of leeway.

I think the wording of the instruction has perhaps encouraged you to be over zealous! When I have my "sweat shop" mass producing these things on a Thursday evening, I tell them to be generous with the solder fillet and then clean up the sides until the tappet is a very easy sliding fit in the trays - ie, it easily drops out under its own weight - and perhaps that would be a better wording for the instruction. It is worth mentioning that with such thick material, there is often a fair variation in the extent of the etch cusps (even on the same fret), so although - for example - one tappet fits in its raw state, others might not. So given that, my way of wording might not be the best.

The reality is that the locking remains very effective despite a fair bit of clearance, whereas, if things are a bit on the tight side, it all very quickly stiffens up to the point of becoming unworkable. I would be very interested to hear your views when you have a few locks up and working - am I being too generous with the clearances, or should I be less prescriptive to builders? Either way, tweaking the instructions is no problem.

Very Best Wishes,

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Colin Parks
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Re: Mk2 Lever frame musings

Postby Colin Parks » Thu Nov 01, 2018 8:50 am

Ah, I seem to have mis-read the instructions Howard!

That quote about removing the etched edges refers only to the port openings. Never mind, there are a few spares, so I shall carry on and fill the edges of the remaining tappets with solder. The clearance of the tappets in the tray slots comes out at about 0.2 mm, which is consistent across the trays tested so far.

...and I had made such a neat job of sweating the parts together without any excess solder - for once.

Colin

JFS
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Re: Mk2 Lever frame musings

Postby JFS » Thu Nov 01, 2018 12:00 pm

Colin Parks wrote:Ah, I seem to have mis-read the instructions Howard!

That quote about removing the etched edges refers only to the port openings. Never mind, there are a few spares, so I shall carry on and fill the edges of the remaining tappets with solder. The clearance of the tappets in the tray slots comes out at about 0.2 mm, which is consistent across the trays tested so far.

...and I had made such a neat job of sweating the parts together without any excess solder - for once.

Colin


Well I did not want to say anything... [could be interpreted as ... I did not look it up to check!]

There is a bit of a catch 22 in jobs like this in that it is all a lot easier with a bit of experience, but by definition, you have no experience when you do the first one! My suggestion would be to get a couple of locks done and working as soon as you can - there are a few "easy" ones in a layout such as yours - and you can post your thoughts if you want feedback to help you stay on the straight and narrow.

I have every confidence that it will all work out - after all, not everyone has gone to the trouble of actually measuring the clearances...

Just a quick question - how far have you got with the other mechanical bits? The crossheads and cam plates are much the trickiest aspect and I would be interested to hear how you found/find them.

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Colin Parks
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Re: Mk2 Lever frame musings

Postby Colin Parks » Thu Nov 01, 2018 6:50 pm

Here are a couple of photos of tappets. The first is as soldered and not finished in any way. I will fill the channel with solder, but the job looks quite neat as it is.

IMG_8983 (2).JPG


This close-up shows the extent of my folly with the file: There is 0.5 mm side play on the r/h tappet. The l/h example fits just as it is, bearing in mind that the tray slots have rounded corners.

IMG_8988 (2).JPG
IMG_8988 (2).JPG (100.78 KiB) Viewed 504 times

JFS
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Re: Mk2 Lever frame musings

Postby JFS » Thu Nov 01, 2018 10:41 pm

Press on Colin - both will be fine!

If you do find that the thinner tappet tends to make slack-ish locks, it is a simple matter to solder a bit of etch waste to the insides of the slot on an unused tray, but I would be surprised if you were to find that necessary - I never have (so far...)

Edit:- I also suggest that you fold up and assemble your trays etc soon-ish - you will get a better idea of the fits when you are putting your tappets through a full set of trays.

Very Best Wishes,

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Colin Parks
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Re: Mk2 Lever frame musings

Postby Colin Parks » Fri Nov 02, 2018 12:31 am

Yes, Howard, the trays will be next on the to-do list.

To repair the narrow tappet, I had thought about soldering a strip of n/s from the edge lever frame sheet. Unless something goes very awry, it will probably not be needed.

Colin

JFS
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Re: Mk2 Lever frame musings

Postby JFS » Tue Nov 20, 2018 9:36 am

Certain members of NAG (AKA the Sweatshop), having been busy at their Thursday night meeting for some weeks now; here is the state of play with the 54-lever Frame for John Elliott's Leeds City Wellington - just a bit of paint needed...

Wellington Frame bare metal.jpg



.. and perhaps also some locking - for which here is some of the preliminary design.

Wellington Locking design 1.jpg


I think this bring my total of MkII levers to 149... there can't be too many more to go...??

For those interested and by way of background, here is the Box Diagram for Wellington as (we think) it existed in the late fifties. It is not without its points of interest.

Leeds Weelington Box Diagram v1_0.jpg


Best Wishes,

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Colin Parks
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Re: Mk2 Lever frame musings

Postby Colin Parks » Tue Nov 20, 2018 5:45 pm

That is mightily impressive Howard.

Is this frame for a different layout to the 'Leeds City the Midland Side' magnum opus? That must have taken hours of filing and shaping by your work group to fashion all those levers.

I was going to ask another thing: in your instructions, you specify taking the etched cusp off certain edges, but did you file away all the cusps as you would with an etched loco kit? I have left cusps where they are not in the way on the components and it looks OK (to lazy me).

Progress been very slow with the locking mechanism for my frame, but it has now got as far as the tack-soldering of the frame stiffeners (p. 13 of 27 in the instructions, though I doubt this is half way in practical terms). I ordered the extra long (100 mm!) 0.8 mm drills for drilling the trays. The came from a company called Pages of Tools, delivered in two days. I note that the pairs of holes in the half-etched ends of the trays are large enough already. That must have something to do with the etching process I suppose.

Looking at your pictured locking frame chart, it looks rather complicated and there seem to be some special locks here and there. The chart presumably shows just the bridles and nibs etc. on the front of the trays - or is it wise to avoid using them on the rear unless absolutely necessary?

Ah, so many questions...

Colin

JFS
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Re: Mk2 Lever frame musings

Postby JFS » Tue Nov 20, 2018 8:05 pm

Hello Colin,

Many thanks for the kind words - and feel free to ask away - that is what the thread was for I thought (even though I did not start it!). The filing is a lot easier when you have done as much of it as we have!

This frame is indeed for the same layout - just for the adjacent signal box. At the moment, this is worked from a temporary bank of switches, and I happened to be working the box at the last running session when a train, running under clear signals, took a wrong turn into an occupied platform. Embarrassing enough, but needless to say, there were about 10 people watching... Maybe others can work complex layouts without mistakes but not me! My only excuse is that there were three movements on the go at once...

Once this one is up and running, there is just the three sets of hidden sidings to sort out. And yes, we might yet have lever frames for those - now we are so good at building them...

Just regarding etch cusps, the issue is only important where the edges form working surfaces but obviously, in the case of the levers, they are "on show" so you will want them to look their best. I think I mention it in the "instructions", but it is as well to stress that on metal as thick as 0.7mm, the etch cusps vary a lot not only between sheets, but even across the same sheet. Just looking at the tray side in your photo - and judging by what you say about the drilling, it is very different from the one I have just been working on - which is a bit under etched, whereas yours is a bit over etched. But the next one might be just the opposite. In the design, I have tried to work to a happy medium which avoids the need for a load of filing at the one extreme versus a sloppy fit at the other. But as I say, the good news is that the design is pretty accommodating and you will soon get a feel for what works well.

The locking design is actually a bit more complex than it looks and in quite a few places there are bridles both front and back. On the drawing, the four channels are shown next to each other. Closer image here:-

Nib Chart -1.jpg


Brown and blue bridles are on top, green and red on the back. On the CAD, I can turn the various layers off so that I can see what is where. Obviously, the more complex the locking the more you need to use every channel - but clearly, there are advantages if you can get away with only using the front ones!! In this locking, there are also a lot of "conditional" locks which means that there are "swinging pieces" (about 16 of them) attached to the front of the bridles. Accommodating these means that you either have to make a "bridge" in a front bridle to take it over the swinging piece, or fit the bridles in the rear channels. On the seventy lever frame, pretty well all the channels were full!

In fact, using the rear channels is a lot less of a hassle than it might seem as the tappets can be easily disconnected from the crossheads by means of the split pins so that they can be slipped in and out to fit the rear bridles.

Hope that helps, and looking forward to seeing further progress!

EDIT:- just spotted a rather obvious mistake in that version!

Very Best Wishes,

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Colin Parks
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Re: Mk2 Lever frame musings

Postby Colin Parks » Tue Nov 20, 2018 11:19 pm

Hello Howard. The tray holes present now problems really and it is probably easier not to have to drill through the half etched parts of the trays. It certainly saves sixteen drilling operations!

That diagram of yours looks incredibly complex to me and I have given up looking of the 'obvious' mistake (though I did wonder about the adjacent nibs on 26 and 27). How on earth did you go about deciding which bridle goes in which tray?!

Colin


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