I have had the test etches back for some time and have had a play with them. This is what they look like back from the etchers:
I did find that I had made a number of the components to fine. I had prototype information, so I had made things like the balance levers to absolute scale and this is too delicate, certainly for 4mm. So they look beautiful in the etch but would not survive on a layout. Fortunately, I had also done an etch of the arms and signal components in 7mm, so I was able to do a little bit of 7mm modelling. This used a Lochgorm Models etched post and my design of base is where it gets too (sorry, slightly fuzzy picture):
I also got the first of the 3d prints back from Shapeways and these are very good indeed, so I am well chuffed with them! They are slightly difficult to photograph but here is what these look like:
I need to make a couple of tweeks to these and get a revised print done of them. I have a miniature etch for the handles done, then I will make a few resin copies of them and they are done!
I also had the finials and lamps printed; the lamps worked fine and so did the finials in 7mm but they proved far to fragile in 4mm – so again I need to make a few key elements overscale to be able to use it.
Whilst my orders for earlier work are underway, I have done a bit more drawing and have now drafted up some lamps for the signals; as below:
I have also managed to sort out a drawing that I did some time ago for a water column. The larger of the models for 3 D printing need to be hollowed out (to save on the printing medium, which is charged for by its volume). This took some time to get right, as I had multiple different parts I was working on.
So these have also be sent of to Shapeways for printing. As before, I will use the lamps as masters for lost wax casting (another new trick to learn!) but the water column will be used as a master for some resin casting (the old dog really is going for lots of new tricks) – it will also need an etch for its operating arm.
However, lets see how good they come back first – as I think I am probably counting chickens prematurely here……….
I received the test etch back from the etchers and after a family holiday (Lisbon – hot but great and with fab trams – see below………) I have had a chance to look at it.
I still have some things to learn, as where I have drawn things up at 4mm the smaller elements have come out a bit fine. so things like the framing around spectacle plates or the cross to the centre of the brackets is a bit too delicate to use. Also, I made a number of the fold lines and the holes are a bit too small so need to be drilled out. Thus, whilst the 4mm ones are usable, they can be done better so I am going to edit the etch.
I also included the signal arms etch at 7mm and this is much better. Whilst one or two elements would benefit from a slight redraft, it is definitely usable and therefore I am just in the process of some 7mm modelling (excommunication from the Scalefour Society?). I’ll get some posts up when I can get it a bit further.
In the meantime, I have also managed to have a bash at some 3-D modelling on CAD to get some finials made up. The idea will be to do an initial set via 3-D printing and then to use these to make some lost wax castings. Whilst these are available via MSE as a whitemetal casting, they are very delicate and will last very little time in my clumsy mits. I will do a lamp via the same route for the same reason.
Anyway, this is what the 3-D model looks like (actually the final version has a sprue coming of the top to support the top of the finial but it rather blocks out what it is you are looking at):
And to give a flavour of the trams in Lisbon:
I have not actually picked up a modelling knife or soldering iron for a couple of weeks now; largely because I got a bit of a bug for sorting out the etch artwork.
I have now completed, I hope, all of the artwork I will need for all of the signals that will be required on Glenmutchkin. Indeed, it should do all the signals I and just about anyone else ever needs for any scheme based on the Highland era!!!!
I am fortunate that I have a couple of an 1895 McKenzie & Holland catalogue and a further partial copy from a bit later. I have also been provided with a number of really good drawings of bracket signals from M&H, prompted by my ramblings on the web. This has given me with a pretty good handle on how they were constructed and I can draw up rather more comprehensive (and a little more specific to the Highland) artwork than are available form any of the other sources.
So this is what I have come up with. Firstly, an etch of all of the arms, balance weights and a track mechanism for raising the lamp to the top of the post (I think this was peculiar to the Highland):
and then an etch that includes the large brackets used for the multi-doll signals and all of the support brackets and landing.
and this one is the smaller bracket; used on twin doll signals:
I have been recommended to use PPD as a first port of call for etching, so they have been winged off tonight. Lets see what a week or so brings us…………..
As this is now out of copyright, an article by OS Nock on the Highland’s signals from the Model Engineer might be of interest too – it may even show what I am trying to make in the etchings a little more clearly.
And for my next task, I am going to have another bash at the water column and the finial; more on this when I think I have been successful!
No, this is not the end. It is not even the beginning of the end. But it is, perhaps, the end of the beginning. Interlocked Lever Frame – Part 4
With thanks to someone else for the quote.
I managed to get all of the locking bars, installed over the weekend and the dogs (the teeth that engage in the sliding bars) to get the interlocking going. And this is what I get to:
This shows all of the components assembled in place. The dogs engage in slots in the sliding bars but the dogs have angled sides – so if nothing holds them in place the movement of the slider pushes them to one side and the slider can move. When another slider is in the way (ie there is an opposing lock set) then this can not occur – so it locks shut.
To stop the sliders popping up when they encounter a lock, a lid has been fashioned. I wanted all of the locking to remain visible, so this is just a skeleton.
I did find that the angles of the slots needed to be just over 45 degrees for the locking bar to move easily and they also need to match the dogs quite neatly. If I do this for real, I think some lost wax masters and then castings will be required to ease the process of manufacture.
The frame does lock well and neatly. Of course I made a few errors in where slots were to go but having made it from plastic, these were actually quite easy to sort out. What is more significant is that there is some slop in the levers – this occurs worst where the yoke of the bar that runs through to operate the toggle switch and sliding bars goes over the base of the lever. The hole in this is a bit too big and it means that the lever can move 30 % of its intended movement before it makes the sliding bar move and hence encounter the lock. This does slightly defeat the object of the locking and will need some work. I have an idea of linking the two more physically but if this does not work, then it may be back to the drawing board.
All in all, it works though and it is quite fun working through the desired move, working out what then needs to be thrown and in what order – although this may send my team a bit over the edge in the heat of an exhibition! However, some manufacturing refinement is going to be needed to make it work better. I remain tempted to use the potential kit that might be available but this makes the locking invisible and I am not so certain about this. Food for thought!
And this is the locking chart that I think is right:
If people out there think there are errors in this; especially the locking chart (locking logic is a bit mind twisting) then please pipe up as I will be building it soon!
Whilst they are not without their frustrations (they are delicate for example), I was slightly surprised to have enjoyed building and using the signals as much as I did. Therefore, Glenmutchkins will going a bit more large on signals.
I am assisted in that the Highland seemed to follow the trend of the pre-group companies and be fairly lavish with their signals. Taking significant cues from my sources of inspiration, Wick and Kyle of Lochalsh, this is where I have got to with a signalling plan.
As can be seen, there is a fair amount to this as I have assumed that there is a junction off scene that is signalled from the station cabin (although this is still under review) and not only is the yard signalled onto the running line but both the run around loops and the shed are both signalled. It looks like this will be a 45 lever frame, so there is a fair amount to do……………
A particular signal to note is the one with arms 17,18 & 19 on it. This is a repeater for arms 15 & 16 so directs locos coming off the yard where they are to go to. This exact same situation existed at Kyle and in addition to being a surprising duplication between the two signals the former is that the signal is situated well up on the bank and faces fairly firmly towards the shed, not the running lines. I do not presently have a photograph that is free of copyright to illustrate this but there are lots in the various text books; try The Highland in LMS Days or LMS Engine Sheds.
I have managed to finished (for now anyway, see below) the first bracket signal for the layout. So here are some pictures:
One error I did manage to include in the build was to make the holes in the balance levers, the crank elbows and the signal arms a tad to big for the operating wire I used. I used 12 gauge guitar wire and the slop that this creates in a 0.5mm hole is rather too much. 0.5mm drills were the smallest I had when I built this so I have invested in a stack of 0.4mm and 0.3mm from drillsuk (on ebay). Next time I will try these really small drills because the thin operating wire does look the part.
The effect of this is to allow the arms to slop too much and they will not be capable of being made to bounce properly. This signal will be in a cutting of the proposed layout, so I will have to replace the wire with something a bit thicker to overcome this.
You live and learn!
I am also having a bit of trouble with the MERG servo drivers; I may be cooking them with my power supply so this needs a bit of work too