This is a blog where I will show the trials and tribulations of model builds as they happen
Category Archives: MOK 8F 8425
The build of an MOK LMS 8F kit. The aim of the build is to represent 8425 one of the class built by the GWR for the War Office and subsequently passed back to the LMS.
Stepping back to my last post on this where made a start on the tender.
It was at this point that I realised that I was missing the whitemetal castings for the tender. All the brass ones were present and the whitemetal castings for the loco were there but I couldn’t find those for the tender. Now I bought the kit second hand at a decent price so i wasn’t too perturbed. I knew that I had drawn up the dome and water filler having turned replacements for the Princess and a look through my spares box revealed that I had a few bits in hand.
Stanier Tender Spares
At this point I was really only missing brake hangers, Axleboxes and springs and the water scoop. I had a feeling that I might have some etches for the brake hangers elft from the Princess as I had used cast replacements on the tender. an I had some 3D printed shoes so I set of looking for those. I looked through one box of etched spares without finding them and then looked at another small box on my bench. Having picked up that box and searched it to no avail I noticed a round plastic tub that it had been sat on. Opening that revealed the missing tender castings. So now I have everything I need I just need to get back on with it.
I was going to add that not long after the last post I discovered that the whitemetal castings were missing from the tender so in spare moments I have been looking through the spares boxes and examining working drawings that I have created to see what I ultimately need to buy. I have already turned some spare rear tank vents and drawn up the water scoop dome, tank filler and brake vacuum cylinder and a number of the various rods etc. are present cast in brass. This left (so far) axleboxes and springs, water scoop and brakes hangers/blocks. Now I have spare brake blocks from the Princess and while looking for the spare etched hangers from the Princess which I didn’t use because I had been supplied with nice cast ones I found the plastic pot with the missing castings. Now admittedly some of these are a bit ropey so I will be replacing some of them anyway but I now have the ones that I would struggle to remake.
The rebuilding of the Princess has reached the stage of needing to test the chassis before fitting the body. I don’t have a layout but I do have a test board with various diameter curves on it. Unfortunately said board lives in the shed and when needed is temporarily erected in the cloakroom. Over the last couple of days the weather here has been really windy making bring the board in undamaged quite a precarious proposition so in the bits of time that I had in between looking after Chris and doing the various household chores I decided do pick up the Just Like The Real Thing Stanier tender. This came with my JLRT Royal Scot but needing a welded tender for the 8F now that it’s changed to 8425 and having found the spare teched sides and rear panel for the MOK version I am now building the JLRT tender bt fitting it with the MOK welded spares and then I will swap the tenders and use the MOK tender for the Royal Scot and the JLRT tender for the 8F.
I bought the kit second hand and the gent that I bought it from hadn’t taken into account the sheer weight of the JLRT cast boiler when packing it. As a result it had shifted somewhat in transport and it had pretty much crushed the inner cage for the tender by the time it arrived with me. Much careful straightening has got the cage back into shape and soldered together and a good start has been made on the inner frames.
Having finished the Princess I have promised my good lady that the 8F (which she bought me in 2010 would be the next loco to be finished. So in the spirit of things I took the pretty much complete tender and the loco chassis along to Stafford so that I had something to talk to people about in between dealing with the modelling competition and the Sunday display of members models.
I was surprised but not too dismayed when three separate people advised me that 8F’s didn’t have water pick up gear fitted. I say not too dismayed because I have no intention of taking it apart to remove the water scoop and associated fittings and it will solve a little niggle that I have had since deciding to model 8425. 8425 had a welded tender and Dave Sharp does provide sides/rear plates to make up a riveted tender when originally building the tender to be for an LNER 06 I chose the riveted sides. I never felt confident that I could remove the riveted sides and fit the welded ones and as I couldn’t find the welded ones I feared that I may have cut them up and used the metal to make other parts.
Fast forward to about a month ago, while looking for something else, I found that by good fortune I did keep the welded side overlays. Also in the stash as mentioned on Nick’s current build thread, I have a JLRT Rebuilt Scot. So I intend to swap the tenders and use the Scot tender built without the water scoop and fittings with the MOK welded sides which are a perfect fit when dry fitted over the JLRT etches.
I have made a small start this evening and I thought I might have to make a new anvil for m rivet punch but it seems I had already made one for smaller spaced rivets so that was a bonus.
In between times I have managed a little more on the 8F. The next job was reassembling the brakes. One thing that has bugged me for a few years is that one of the clevis castings hadn’t fully formed when casting.
Misformed Clevis casting
It would have been easy enough to just solder it on and have done with it but I remembered fellow modeller Tony Geary making some clevises to add detail to the brakes on one of his builds so I decided to have a go at one myself.
I started with some square bar and turned a round spigot on the end. Then I reduced the next few millimetres down to the size of the arms of the clevis using a small Dremel burr as a milling cutter
Dremel Type Burr
a bit of hand filing gave me the basic shape
Basic Replacements
Then I drilled a couple of holes in either end of a stub of brass bar and temporarily soldered the two parts into it. This allowed me to cut the slots. I do have a full sized slitting saw for the mill but a couple of years ago while in one of the cheapo trading stores I bought a set of slitting saws for a Dremel type tool (notice a theme here?). I think they were a fiver for the full set.
I fitted it into the mill with a 0.8mm blade (the pack has several different thicknesses from 0.4 – 0.8mm) and I was really surprised at how little run out it had.
This is the end slit and then finally the finished clevis
Having worked out how it all fit turned out to be the easy bit! Assembling all the elements together with the balance weights was like trying to plait fog. You have to slip the cross pin through eight separate holes in the subassemblies. Much muttering ensued before I got it all together.
MOK 8F 8425 Water Scoop MechanismMOK 8F 8425 Water Scoop MechanismMOK 8F 8425 Water Scoop MechanismMOK 8F 8425 Water Scoop Mechanism
Although they are shown on the isometric drawing there is no provision for or mention in the instructions of the support adjuster rods for the scoop. I made them from some lengths of rod and microbore tube.
MOK 8F 8425 Water Scoop Mechanism
I have made a few of these Stanier Tenders by now and this is certainly the most detailed that I have done to date.
Today I finally cracked my enigma. One of the reasons that the build stalled back in 2018 was that I couldn’t for the life of me work out how the water scoop mechanism went together.
At this point I need to say a big thanks to fellow Guild member Ian Allen for pointing me in the right direction. As with all things when you know what to look for it is there in the instructions it’s just not that clear.
My problem was the arm that goes alongside the inner chassis.
MOK 8F 8425 Tender Water Scoop Mechanism
I initially had it located in between the clevises at the front. When it needs to fit behind. This meant that when trying to fit the wheels the rod fouled them
MOK 8F 8425 Tender Water Scoop Mechanism
Once I knew this it made things a bit clearer then I discovered that I had the linkage that the water scoop attaches to upside down.
MOK 8F 8425 Tender Water Scoop Mechanism
With that corrected I was able to get it to fit together. It still needs fixing permanently in place but I have the balance weights to fit yet so I will wait until I have done that before making anything else that I might have to undo!
I managed to progress the tender for the 8F a little more over the weekend and now the outer frames sport axles boxes and springs.
MOK 8F 8425 Tender underframe – springs and hangers fitted
As can be seen from the inside, I soldered them on (with 100 degree solder). Before fitting them I added a small blob of 100 degree solder to the back of each spring damper. Once I had soldered the spigots from the inside I pressed on each damper with the none pointy end of a pencil and used the RSU again from the inside to quickly melt the solder, firmly attaching the dampers.
As an aside, as I got them out to the box I noted that one of the dampers had broken off and I spent sometime reattaching it using 70 degree solder. I was just about to fit it when I saw that I already had the six that I needed. Dave sharp must have noted the broken one when he packed the kit all those years ago and popped in an extra.
Over the weekend in between checking over the Princess Firebox drawings, I fitted all the new lamp irons and I am happy that the upper tender is now complete.
Today I have made the final set of lamp irons for the 8F and thought I would share the method because it occurred to me that while I have used the mill the same result and basic method could be followed by someone with a file.
I started with some flat nickel bar
Nickel Strip
I cut off four 40mm lengths and soldered them together.
4 Strips soldered together and Cleaned up
Once soldered together I milled all the edges flat. I needn’t have done the ends but with the mill it was a simple task. Here I have milled out the front of the iron.
Milling four irons at a time
Then I turned the block over and milled out the rear
Four irons milled but still attached to each other
This is the finished job before cutting off with a piercing saw and separating them.
Lamp Irons ready for finishing with a file
The finished individual lamp irons ready for final clean up with a file.
From the 40mm strips, I got eight lamp irons and I have enough material left already soldered together for a further eight which I will cut and put in the spares box.
Needing a bit of a break from re-drawing the Firebox for the Princess my thoughts turned to front lamp irons. As I was working out what was needed I got side tracked by working out how I might machine some of the double lamp irons that the GWR fitted to the 8F’s that they built
Milled Lamp Irons
Not the best photo as it’s a snip from a much larger photo found on the net to illustrate what I am talking about. The MOK kit does provide etches to make up this version of the lamp irons but I am not keen on etched lamp irons. I also thought that I would like to do them from nickel as the rest of the kit is nickel but I didn’t have any nickel bar thick enough. I do have some 5mm rod so my first step was to machine the end square in the mill.
Then it was a case of working out how best to mill out the bits in between the lamp irons.
I milled a groove down one corner of the square section and then rotated the part to carefully mill from the opposite corner to leave the two upright irons
Milled Lamp IronsMilled Lamp Irons
the tops were then rounded with a file before cutting off the main piece. I could have transferred the work piece to the lathe and part it off but I just cut it with a piercing saw them popped it in the vice jaws and milled the bottom flat.
Back when I got this kit 12 or more years ago there were no buffer heads in with it. Apparently they were supplied by Ron Chaplin and he had just retired. I really should have pestered Dave Shap for some replacements but time went on and it’s too late now. To get around it I imported the drawing into Fusion 360 and scaled it I then drew up the head to get dimensions and from there a happy few hours were spent turning some from some mild steel bar.
I wasn’t thinking when I picked up a 6ba screw/nut thinking it was 8ba. I drilled out the buffer castings to take 6ba before realising my mistake so I made the buffer heads to take a 6ba nut. Fortunately I found some suitable springs.
Recent talk of printing works plates by guys on another forum got me thinking about the fact that I had managed to find an auction house image of the actual plate fitted to my loco which I downloaded. I managed to find it again today and shared it for comparison purposes only.
When scaled and enlarged the font doesn’t match anything that I could find so I ended up drawing each letter/numeral individually.
The images are much enlarged with the text and rim being only 0.2mm deep
Some time ago a fellow modeller who was building the same kit had some 3D printed brake shoes done. He very kindly sent me a set and they have been sat waiting patiently ever since.
While working on the other bits over Christmas I have been pondering the best way how to tackle fitting these. The brake hangers on Stanier tenders are curved so to replicate these my thoughts ranged from turning circular strips from sheet to bending strips from flat bar. In the end I gave my self a mental kick and thought why are you trying to ‘save’ the castings, you will never use them now that you have fitted 3D printed replacements.
So the next thought was right I need to remove the cast on, shoes from the hangers. Ian, the guy that had supplied the printed shoes also sent a note with some suggestions as to how to go about it. His first suggestion was to use the pips on the cast shoes as the location for drilling out the hole for the pin. I duly filed the pip down on one side of each casting until it was just a witness mark and then punched it. I used a pin vice to drill the first one and though sod this for a game. I drilled a hole in a lolly stick to take a 1mm drill bit (the same sized hole as the top of the hanger). I popped the leg of the hanger in the vice along with the bottom of the drill bit, which was inserted through the hanger and then the lolly stick. This held the casting firm enough to drill through it with my Proxxon mini pillar drill. The rest of the drilling was done in no time.
I tried the same set up to hold the casting to file off the bulk of the cast on shoe but using a file was hard work so my thoughts turned to milling them off. To use the mill I needed to hold them much more securely than a piece of lolly stick would allow. So I made a fixture from a piece of brass bar.
Fixture for holding brake castings while milling.
For the first side I just drilled a couple of holes at the appropriate spacing to hold the leg of the casting and the drill bit passed through the hole as before.
For the reverse side I didn’t have the leg to give me the secure holding so I milled a bit off cutting art way through the leg hole
Machining a Fixture for holding brake castings while milling.Fixture for holding brake castings while milling.
Which gave me this.
Fixture for holding brake castings while milling.
Once both sides were milled I used a mini sanding drum in my Dremel to take off the last bit and restore the inner curve.
MOK 8F 3D Printed Brake shoes fitted
The last task was to insert some brass pins and superglue them in place while allowing the shoe to still pivot.
Next job is refitting them to the tender chassis as I had already fitted them some time ago.
Once I had sorted the errant part 146 and made the tender top fit I also fitted some rivets strips around the edge of the top plate that I had missed, moved on to adding the details to the tender front.
Brake and water scoop windlasses, water gauge and water scoop indicator rod. Plus another couple of levers whose role escapes me.
MOK 8F 8425 – Tender front detailsMOK 8F 8425 – Tender front detailsMOK 8F 8425 – Tender front details
The windlass handles were soldered to the cover castings using 295 degree solder and then the castings were soldered in place using 100 degree solder to make life easy. The backs were tinned with the 100 degree, add a drop of flux, pop them in place and a small waft of heat from the micro flame and they were fixed. The water gauge was treated in the same way. a small blob of 100 degree solder applied to the pin pop in place then waft with the flame until the solder melts and the castings sits down in place. If it moves out of position it’s easy to reheat and adjust with tweezers.
A little discovery here, having made the replacements parts yesterday afternoon was all about fitting them. Besides fitting the castings I started to fit the small pieces of etch that represent the backing plates for the rear steps and those just above the foot plate on the rear of the tender.
MOK 8F This is where it fits
Once I had added them I noted that there was quite a big intermittent gap along the bottom. I read and re-read the instructions and couldn’t see where I had gone wrong. There are not too many bits of etch left and one of them that I couldn’t find a home for is part 146. After much head scratching I worked out that although completely omitted from the instructions it fits as outlined in red on the image below.
MOK 8F Part 146- Not mentioned in the instructions
This is on the top side of the tender footplate (thankfully at this point I had only retained it by the tabs so it was easily removed). As if omitting it from the instructions wasn’t bad enough, there are no positive locating marks and in this photo I have it slightly too far towards the tender rear so I need to take it off and move it back a touch or the tender body won’t sit down and close the gaps.
What was I saying about soldering allowing you to take it off and adjust it…
Wow, 2018 since I last looked at this. No wonder Chris is muttering.
Any way I picked it up again yesterday and I started by making a couple of replacements for castings and turning the tank vents so that they at least sit flat and vertical to the tender top plate.
MOK 8F Whitemetal castings
These are the water scoop dome and brake cylinder. The latter is oval in shape and the former quite badly pitted.
MOK 8F Replacement turnings and cleaned up vent pipes
Replacements machined and since this photo was taken fitted.
This is what it looks like with the overlays on the body. You get two options included in the kit either welded or riveted. I chose riveted because it adds a little more to the character.
LNER 06 (MOK 8F) Tender Top – Outer Skin
LNER 06 (MOK 8F) Tender Top – Outer Skin
LNER 06 (MOK 8F) Tender Top – Outer Skin
These latter two show the front bulkhead now it’s fitted and the fire iron tunnel which fitted perfectly.
Before going any further I started to make up the bulkheads which are made up from multiple layers. Here the instructions (or my interpretation of them) let me down again and I managed to get the overlay for the top of the front bulkhead out of sequence meaning that I had to cut a section out of it to prevent having to undo a lot of work meaning that it sits around the lockers not behind them (it was quite easy to do with scissors due to it being half etched). It isn’t visible in the end result but I know I had to do it.
A few days off over Easter saw me make further progress on the 06.
Shaping the curves of the inner tender sides was interesting because in my ignorance I had chopped off one end of the etch which contained the marked etched bend lines and although I still had the piece that I removed I couldn’t realistically realign it. So some careful measuring was in order.
I annealed the tops of the sides where the main bend was to be – I did this a couple of times during the process.
LNER 06 (MOK 8F) Tender – Bending the Flare
LNER 06 (MOK 8F) Tender – Bending the Flare
LNER 06 (MOK 8F) Tender – Bending the Flare
LNER 06 (MOK 8F) Tender – Bending the Flare
In order to bend the front curves of the tender sides which were very close to the half etched line for the location of the front bulkhead I soldered in a couple of strips of scrap to stop it bending on the half etched line instead of where I wanted it to.
Once happy I soldered in the rear bulkhead and started to add details.