Little and lit

[richbrummitt]

---edited to correct images not displaying---nothing further has been added---

 

 

This is not going to have too many words because I don't have the proper use of my right hand at the moment and this is making a lot of ordinary things difficult, typing included. Sorry. I've collected the majority of the pictures from the original topic and tried to tie them together with a few snippets to convey the story without too many of the mishaps. If you want to read the unedited original please see here

 

I wished to make something small and almost for the sake of it for the challenge. I actually had need for one of these and the idea was sparked when visiting Didcot on the 'behind the scenes' RMWeb tour that was kindly organised by Castle. The model is of a 19th century GWR point disc. There is one of these under a very small tree near to the transfer shed at Didcot, although this has targets for both directions.

 

 

 

I wished for it to not only work, but also to light up! I ordered some 0402 package size LEDs, which I hoped would fit inside a 1mm diameter hole just over 1mm long, otherwise it wasn't going to be possible at scale size. I also prepared some drawings from those that featured in the Broad Gauge Society literature many years. Each grid square represents one inch.

 

 

I ordered plenty of LEDs and it was a good job because after losing a few and some false starts I consumed at least 8, although there are only two in the final model.

 

This is how I imagined the assembly would look

 

 

On the left is the assembly and on the right a cross section. Rather than having an arm this type of signal has the top portion swiveling around to show either red or green faces with corresponding lenses to the engine driver. Due to the fact that they were connected into the switch operation they actually only tell the driver what route is set, unlike later independent signals with detection.

 

The small white cuboid at the top centre of the right hand view is the LED. This is attached to the central tube, with 0.3mm ID and 0.5mm OD, which is fixed and used for one electrical feed. The top wasl be file down, except for a small portion bent around at the back to fix to the solder pad on the back of the LED (this looks a bit odd in the drawing). Inside this is an insulated wire for the other electrical feed that I obtained from a redundant motor armature. Around this tube is a further tube (0.8mm OD with the ID opened up to be a nice running fit on the assembled inner tube) attached to the rotating head of the signal. This was made from either steel and is 1.5mmOD centre drilled 1mm to create enough space for the LED assembly. This rotating outer assembly has an operating arm beneath the base board to attach with linkages into the TOU (turnout operating unit). In the drawings the very top of this part is not shown. It will have to be added afterwards and needs to be removable in the case I have to change the LED because the central assembly cannot be made to fit down the 0.5mmID tube because the LED is a bit fatter than I thought it would be. The rotating outer assembly will pass through the base. I hadn't worked out how I was going to produce the base when I created this drawing, hence it is not drawn.

 

Here was my test piece of one LED unlit:

 

 

lit:

 

 

The rizla just stops the supply shorting and gives me something to hold!

 

Here's a quick step by step:

 

1. Shaping the thin wall tube (0.3mm ID, 0.5mm OD) to relieve one side for the enamelled wire to exit. The little upstand remaining after filing will be used as one solder point for the LEDs.

 

 

2. The first LED soldered onto the tube. I found it easier to hold the LED by sticking it into a small piece of Blu-Tac. Tacky wax might have been better, but I don't have any. Don't get the soldering iron on the Blu-Tac or the tip could suffer: the stuff goes horribly gooey when burned.

 

 

3. The second LED attached to some enamelled wire and inserted down the tube. Yes, a motor was harmed in the making of this. It wasn't an expensive one and I hadn't found a better use for it yet. The enamel (assuming that's what it is) on the wire has plenty of heat resistance.

 

 

4. This is what is hopefully the final assembly of the inner. It would appear to be small enough to fit in the 1mm diameter hole as required but I'll have to see when I've made the actual 'disc'. (it did)

 

 

(If you're thinking that something looks different in the last photo you'd be right. The first three photos show the first attempt that went something like right with two LEDs wired in series. This wasn't robust enough and they wouldn't both light on the 3v battery I planned to use so I did some thinking and wired them in parallel. Both LEDs are soldered to the tube at the bottom and joined to the wire at the top.)

 

The outer part was made from 1.5mm steel drilled through on the lathe and cross drilled very carefully with a 0.3mm drill in three places with 90° separation around the circumference before parting off carefully. This was soldered onto the 0.8mm tube bored out to 0.5mm to allow a sliding fit for the internal piece with the LEDs seen previously. The difference in size between the ID of the steel and the OD of the brass was accommodated by swaging the end of the brass tube with a centre punch. The two parts were soldered in a purpose made alignment jig to maintain concentricity. The steel was blackened post soldering to achieve a nice durable weathered black that, I hope, should be durable. It's pretty tough to hold a small coin whilst taking the photo so you'll have to make do without. Dimensions are approximately 1.5mm diameter by 1.5mm tall, which means that it is almost to scale.

 

 

The next part was the top. This allows access to the lamp should it need attention. I had hoped that it would be possible for the LED section to be removed through the base but it quickly became clear that this would be very difficult, if not impossible, to achieve.

 

 

Above is the beginning of the work with the top necked in and the larger radius started. Below is the finished (?) piece before parting off. The bottom was finished off with a 1.5mm drill in the tailstock to allow as much clearance as possible for the LEDs, rather than having a location spigot as I might have done in any other situation. A little Klear was used to fix this little part in place once complete.

 

 

I pondered what to do to retain this speck of steel whilst I parted off. I've done all the turning by hand with a graver for this and needed both hands. I couldn't, therefore, wind a handle with one and play catch with the other. After some thought the best I'd got was to drill up the centre and superglue some wire in this hole, hold the wire in tailstock and not risk pinging the part off into the abyss. I managed to bend the wire but still have the part. Here it is transferred to another pin chuck (yes, I bought extra pin chucks to hold all the parts for this project!) for a photo after blackening.

 

 

Here is the base mounted into the fixture for milling the top of the base whilst still in the milling machine. The part is milled another 0.8mm deep at 2mm width below the base of the point indicator to represent the continuation of the point timber across the 6mm hole the part will occupy in the baseboard when it is mounted.

 

 

Finally a picture with a coin for size reference, a nice shiny 2012 penny, not quite as shiny as the brass part however. The odd shape near the bottom is where I have already begun roughing out a slot that will house the mechanism. I don't think pictures can really convey the size of this piece, or the final assembly, unfortunately.

 

 

The operating lever has been added from 0.008" guitar string through a cross drilled 0.3mm hole. It will eventually be integrated into the point rodding. I planned to create a small display/demonstration board for this piece before transplanting onto Littlemore at a later date. The odd colouring is due to blackening the steel wire and getting it on the brass too.

 

 

This was the first point that I could put some parts together to find out that it might actually operate! With a little paint splashed on (to save me trying to paint it all once it's assembled) and trial fitted together we have a good result.

 

 

Through the right hand hole you will be able to see the yellow of the LED face?

 

Next it needed some targets/faces. I looked for a pair of those 80s 3D glasses but didn't get very far. Red and green acetate was out of stock in the the hobby store and I'm not sure that I'd have given £3+ a sheet for it anyway. I dug into a sheet of signal lenses and punched out a disc of green colour from the sheet with a craft punch tool for eyelet work (kindly borrowed from the wife's tool stash). The red face is being made from 0.005" n/s etch scrap, with a through hole and no lens, and the light will be white.

 

 

I tried to attach it with Microscale Krystal Kleer but the bond was rubbish: it came away on my finger the following day. By some miracle I tracked down the stray part in the (dark blue) carpet and am having another go after having a search on the forum about possible alternatives without resorting to superglue and it's possible problems. This time I'm trying with Pledge Wax (formerly Johnsons Klear). If it sticks this like it does ballast I should have no problems.

 

 

Although the bottle suggests 20 minutes when used for it's intended purpose I left it like this overnight and hoped that the blu-tac came away nicely. The tweezers were adjusted to apply very light pressure like this. It was fine.

 

 

Apologies for the mess in the background.

 

Some pictures of the unit working and lit, but missing it's 'hat'. I had difficulty capturing how it really looks in the flesh, so to speak.

 

 

(on, danger)

 

(off)

 

(rear)

 

Those with the desk lamp on too,

 

(rear 3/4)

 

(front 3/4)

 

and these with just the (not great) room lighting.

 

Some further pictures with it's hat on

 

 

 

I attached it with a little Klear carefully applied.

 

There is a little white marking in one of the grooves that I didn't notice before. I think this is residue from the blackening that remained/appeared after rinsing that was not cleaned well enough. The camera is harsh! It got removed.

 

As mention previously I'd always intended to create a little working display for this item before installing it on the layout at an appropriate stage in that construction.

 

I had some problems here. More details of how it came to require a near complete rebuild are in the original thread

 

Having considered the earlier pictures I did make a few small tweaks. There is some paint needing to be re-applied in the following pictures.

 

 

Another fortunate coincidence of the rebuilding was that the light seen through the lenses is now much less than it was and that pleases me.

 

Further progress was made with the appearance of point timbering, a 2/3 sprue of easitrac, about 160mm of rail, copious filing and various solvents.

 

 

The second button is a push to make switch to complete the circuit and light the LEDs up.

 

The platform face got attached, where it is relative to the point disc when it is transplanted onto Littlemore. After a lot of juggling of paint, glue, &c. setting/drying times and some awkward soldering I'd reached this stage:

 

 

The switch rails worked and the detail has been added and painted. The mechanism moves both the switch and the point disc from the one slide switch.

 

 

Please pardon the slightly wonky looking rodding. I've been harsh on myself here so that you can see the rodding, crank, switch tie bars, fishplates, so the photo has ended up many times full size. I'm feeling reasonably happy with how the appearance is on what has come to serve as a test piece for track painting and ballasting, as well as it's purpose as a base to display the point disc for this challenge.

 

Finally the platform surface is finished and various washes, powders, &c. blend the colours together.

 

 

Some low light shots to show it lit up

 

 

and with the lever pulled giving the road

 

 

Thank you all for your support, comments and input. It has been valuable and is much appreciated.

[jcm@gwr]

Hi Rich,

Sounds great, pity that the attachments are not visible!

Jeff

[Ian Smith]

For someone who wasn't going to type much, that's quite an entry

 

Like JCM I too cannot see the images - I assume they were the ones from the original topic though.

 

Ian

[richbrummitt]

Hi Rich,

Sounds great, pity that the attachments are not visible!

Jeff

For someone who wasn't going to type much, that's quite an entry

 

Like JCM I too cannot see the images - I assume they were the ones from the original topic though.

 

Ian

 

I copied much of the content from the original thread so there is not much new text - just a couple of short paragraphs and some editing was required. I had hoped the images would still work. I should have checked what I posted after I clicked the post button. Sorry gents (and anyone else who couldn't see the images.

[bcnPete]

Absolutely superb Rich...

[Neal Ball]

Awesome!