Category Archives: Workbench (other)
We haven’t had an update on the etching and mastering that I have been doing for the signals for a while.
Well, I have had both the rapid-prototype masters and etching in. Using the former, I have also had my first set of lost wax casting done – in this case for the lamps and finials. This is what they look like – which I think is pretty good and a lot better than the white metal ones from MSE.
and the etching looks like this – brackets, arms, ladders and a few other bits and pieces.
So it was time to make a signal – in this case a fairly simple single arm Highland signal. So using a post from Lochgorm and then my parts for the arms, spectacle plates, windlass, balance levers, ladders, finials and lamp, this is what it has come out like:
and the castings close up looked like this.
So all in all, I am pretty chuffed!
It does mean that I think there is some more signal building to come on these pages……….
In the summer, my 16 year old decided to rejoin the human race (having spent the previous three years on the planet “grunt”) sufficient that he and his mate decided that they might actually want a week away with a boring middle aged bloke. So after some discussion, we decided to go and get some “fest” in at Edinburgh, cycle the Dava way, bag a couple of munros and take in a distillery tour or two.
We stayed at Aviemore so I went on one of my photo recons and whilst I must have been past it several times before I found this rather nice yard hand crane.
I thought it ouzed atmosphere and would make a lovely little model; so I have had a bash with it – again trying to use modern means to make it so that it could be replicated if need be. So other than what I think is a brake at the rear (which I forgot until I loaded the picture up above) I think it is done.
The base piece, sides and the cowl that goes over the base of the main wheel (the green bit) are intended to be etched; the rest will go down the route of 3 D printing again.
So it is time to spend some money with Shapeways and PPD again……….. I have also done some work on the other things that I had etched and printed before; hopefully they will have the little glitches sorted this time; a little present for myself for Christmas!
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!
Less modelling has been achieved this week – due to a combination of work taking me a little more afield than normal and also because I was playing with someone else’s trainset.
In this case, the layout was Barry Luck’s (with assistance of the Mid-Sussex AG of the S4 Society) Brighton Road. It was shown in the carriage repair shop at Horsted Keynes; so we were serenaded by the sound of the real thing (and the occasional burble of a Sulzer as they had a class 33 working too.
Some rather nice photos from Jonathan Hughes are here:
and if you wish to see anymore; then go to here http://www.flickr.com/photos/nimbus20/sets/72157634415164752/
I was not totally idle otherwise, as I have had a bash at producing my own artwork for etching. I think this (it is a bracket for a signal a little like the one here https://highlandmiscellany.com/2013/02/03/first-signal-for-glenmutchkin/) is capable of being etched. I’ll be submitting it too Grange & Hodder soon to find out!
Whilst I appreciate that there are many that are now quite experienced etch designers, even if this started as a means to forward their own builds, I am still taking first steps in this direction so I am pretty proud of the above. Mind you, I might be counting chickens before…………….
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!
The saga continues and I have now made all the trays and the bars that the locks go into. As I have yet to colour the actual levers on the frame, I have coloured these to ease my understanding of things.
As this is an experiment, I am making this out of plasticard/evergreen strip to speed construction. The final thing will be in soldered and milled brass. I have yet to come up with a plate to secure all these bars in place, so they will not flop out as they presently appear that they might. This is what we currently looks like:
I have been warned that I may snap my tappets from the locking bars or something else. This is due to the significant mechanical advantage that the lever has over the through of the bar – if you look at the end view you can see that it is about 10:1, so I can see why I am being warned. Ultimately this is an experiment so I will take it easy with the frame if it breaks I will know that it will need to be tougher next time!