Lamp irons and grab rails
NB: the lamps are from JCT.
The lamp irons are simple enough but thought that I'd share how I tackled these particular items as they are slightly different to the tender lamp irons covered before, hmm a god few years before at that...
The iron's themselves are 3/16 wide and approx 1/16 thick but there's a little more to them than that as looking at my photo's there's a radius where the verticle meets the base which is wider than 3/16. I therefore decided to make the irons from 3/16 square bar and to file down the excess by hand, yes I'm a glutton for punishment...
So the first picture shows the base section on it's side in the machine vice having 1/16 slots machined across it's back, note these slots are in the middle of the two mounting holes already drilled.
I then cut up some over sized lengths of 3/16 stock for the uprights and silver soldered the lot together, this gives me a stick which is easier to work on, I also tapped any parts square that had moved during the heating process .
Next, I took a small amount off the bottom of the base to square the overhangs up so that I could hold the job securely in the machine vice. Placing the job face down I machined the excess from the back of the uprights to just below 1/16 thick. with that done I then machined the tips so that they were all equal and finally machined the bottom of the base until I had an overall size of 3/4".
With the machining finished it was time for a bit of filing, the first job was to tackle the verticle taper, it's 5/32 at the tip. I positioned the stick in the vice just below the top edge so that I didn't file away any of the metal needed for the radius. I checked each iron for a fit of the lamps, I'll go into more details about these later, when I convert them to working lights.
Getting closer to being finished, the base has been filed down leaving the radius at the bottom of the verticle and a slight angle to the tip. To make life a little easier for doing this I machined a shallow slot across a piece of hardwood that the base fitted into and used this as a guide as to how far to file each base down, still a bit sore on the old fingers but got there eventually.
The finished article, the last job was to put a small radius on the end of each base.
Last picture for that night shows the lamp irons and grab rails fitted, the rails were made from suitable pieces of bar and tube which after bending was held in a jig for soldering together. I note in the picture that I haven't bolted the irons on squarely, I allowed play in the holes so can move them easy enough, will sort that tomorrow. The eagle-eyed among you will see the newly filed half circle out of the centre running board, this is for the vacuum standpipe which can just be seen in the bottom of the picture, this was made at the same time as the tender pipe, details of which can be found there. I'll cover this in the next update as it's fitted differently today than it was back in the 30's. I also have three hex bolts to fit to the front of the 2:1 gear cover, I have already marked out roughly where these go, they aren't central as one might expect.
Here's the front including the buffer beam nearly finished all but for the hook and coupling. Standpipe is now fitted although I need to reduce the length of the vacuum hose to get the correct curve, this is a bit clearer in the last picture. I mentioned before that the pipe is held differently today, the difference being that there is no longer an 'U' clip mounted to the front of the buffer beam , today the pipe is held by a flat bracket coming off the top of the running board which is held by two of the hex bolts. I have adjusted the lamp irons as promised, fitted the standpipe, drilled/tapped the 3 10 BA hex bolts (dummies so that I don't damage the paint needlessly) to hold the 2:1 cover and just for fun placed two lamps as appropriate for an express train..
I thought that I'd take another picture with the smokebox door taped in place to get an idea of how the front is looking, the door still needs a little work but it's close, I still need to make all of the hinges and dart gear too and as stated I need to reduce the length of the hose but in my minds eye I'm beginning to see a Gresley Pacific face taking shape....
Onto the working lamps, this picture was taken to describe what I plan to do. You can't see all of the components here but basically, I'm using 5 mm warm LED's (a nice fit with a bulb holder in the lamp opening) which give a nice yellow light. A suitable bulb holder, A turned up piece of PTFE that fit's into the roof of the casting to insulate from the body. The LED's as seen here although I have changed them slightly and for the long negative tab I have replaced this with a strip of brass shim soldered on, both terminals covered with heat-shrink. The casting body is tapped 10 mm and I have bought from eBay some 10 mm plastic grub screws, again to insulate from the body.
The idea being that with the battery pushed up from the bottom it touches the top positive terminal as it presses it against the PTFE insulating spacer in the top of the lamp(there's a nice recess here that a turned spigot of PTFE can be pushed tightly up into. The negative brass shim which slides down the side of the battery is then folded under the bottom of the battery so that when the plastic grub screw is turned a little both terminals make contact as the grub screw is tightened.
The batteries that I have tried are the small LR44 types which are 1.5v, you need 2 of these to work, you can use 3 but it's a little bright and not really enough room in the lamp. I made up battery packs of two using heat-shrink to hold them together, they are a little too delicate for soldering together. Now this does work but it's a little temperamental due to space, that is it turns on ok but needs the grub screw removed to turn off, it's also a bit tight against the LED which can try to push the LED out, The holders might hold the LED in place if the opening was made a little bigger, currently they push in if you cut the securing tabs off the back, however if the opening was reamed out a little this may work better. However, before I start cutting the casting I have since discovered that you can get other batteries around the same size that are 3v lithium and I think that these should work perfectly as you only need one and so they won't be trying to push the LED out. It just needs a little more R&D to get a reliable system, once I have the batteries I'll take another look.
You could, of course, saw the top off at it's neck, drill and tap, modify and have a screw top that screws down to make a contact, that's a little more work although might be the best solution for ease of operation, I don't want to spend too much time on these right now as I've got plenty of more important things to be getting on with but thought that I'd share this info now while we are on the subject..
NB: I still haven't got around to a final fitting, I'll do that when the model is finished.
To start I'll give a list of the components that I've used, all of which are easily available from eBay mostly via 'Bright Components'
1: Bright Components, heat shrink H-01-1.6
2: Bright Components, bulb holder L-B-01-05
3: Bright Components, LED Flat Warm White 120 degree wide angle L-U-02-05
4: M10 plastic grub screws ( actually I went another way, details in description)
5: LR41 1.55v batteries
First picture shows the various parts assembled, ideally a 7 mm reamer would have been better but I didn't have one so used a sharpened drill bit (be gentle), also seen is a small metal spacer that was used to press the bulb holder with LED into the lamp, it's a tight fit which it needs to be to stop the LED being pushed out. you'll find that the holders push into the original openings nicely without the LED fitted but once they have the LED's you do need to open the opening up a little to approx 7 mm to get them to fit. The two white spacers are PTFE (any insulated material will do), the one with the step fit's into the top neck, the other which isn't required if using the plastic grub screw fits between the battery and the securing plate, I'll cover that in other pictures. I have included the M 10 grub screw in the picture although didn't actually use it...I've lost the order details but there are plenty of these available from eBay. I modified the LED contacts, the top contact (positive) I shortened and sleeved with the heatshrink, the bottom (negative) contact has a small thin (approx 1.5mm wide) length of brass shim that was drilled one end so that it slide over the LED terminal and soldered in place, the original terminal was then cut off as close to the LED as possible. The shim is over length in the picture, I trimmed it to size after it had been tried in the lamp with the battery, note it's also insulated with heat shrink.
This is the bulb holder, cut one of the tabs off, this is to give clearance for the negative lead, note the LED has now had it's negative shim trimmed to length.
Next we need to prepare the casting, first, an M 10 tap was used to cut a few threads into the bottom, I then ground out a small channel from the lamp opening to the base with a Dremel cutter, this is to give room for the negative lead to fit without being crushed by the battery or threaded plug. The top PTFE spacer had a step turned that was a tight fit into the casting neck , this is to give an insulated contact that the live terminal will be pushed up against as the screw plate in the base is turned to the 'ON' position. Oh I forgot to add that the top live terminal needs trimming so that when the LED is pushed home it's tip is around the middle of the casting, it's not critical but you must be sure to not let it touch the casting itself.
This picture shows the battery being tried for fit, this pack consists of two LR41 batteries held together with some heat-shrink , I seemed to have lost the details but it was basically heat-shrink that was around 9 mm in it's un-shrunk state. You can just see the PTFE spacer, this needs to be at a height that's just below the lamp opening.
Once happy with the battery fit it's time to insert the LED, as mentioned this first entails increasing the opening to around 7 mm so that the holder is a tight fit, you also need to ground down the LED face itself (unless you can find smaller depth LED's than I that is) . I did this simply using some Wet & dry on a flat surface, it takes a little time but easy enough, I ground off the front face until it was very close to the LED internals, once polished it's nice and clear again, don't be tempted to use too coarse a paper or you may not be able to polish out all of the marks, I finished with 1500 grit and plenty of water. Now some may be tempted to use normal rounded lens LED's and do away with the lamp lens that comes in the kit altogether, I resisted this as it will place the light source out of the lamp which for me would look totally wrong, I do accept though that this would make life somewhat easier. I used the small spacer that just fits into the opening to push the holder home in a vice.
Here we have both the LED and battery fitted with the negative shim tab folded under the battery just awaiting the screw plate to be fitted, in this picture it shows a cut down plastic grub screw but this was a little problematic to do, only having a few threads to screw into an thus changed to a slice of 10 mm studding that I cut a line across it's face for using a screwdriver to fit.
And so here's the metal plate fitted in it's off position, it's literally just one thread and thus not sitting square although this straightens out once turned on, the important thing is it's in and won't fall out.
so...what's it look like, here we see the lamp while switched off, now John of JCT fittings states not to use cyan (super glue) to hold the lens in place, rightly so as it can craze the lens due the glue turning white, however, we have moved on a little and the rubber type superglue works nicely, just use the smallest amount possible in a couple of spots to hold the lens in place. You don't want too much as 1, it could smear the lens and 2, one day you may need to change the LED.
Finally, we have the money shot, a working LNER lamp, I'm quite pleased with the end result, i hope you guys like it too..