7mm MOK BR Standard 4MT Tank

Discussion in 'Area 51' started by P A D, 14 May 2018.

  1. P A D

    P A D Western Thunderer

    Here is the left rear step after fitting.
    20180706_191140.jpg 20180706_191046.jpg

    I then went back to the body and added most of the detail to the fire box. The washout plugs, mud hole clamps, safety valve base have all been added. Additionally, a boiler band cleat from Laurie Griffin was fixed to the front cladding band and the band fixings were drilled out and small brass rivets added to improve the appearance . All soldering was done from the inside with 145 degree solder. The exception was the etched safety valve base which was tinned with 145 and then sweated onto the fire box top.

    This view from the side shows the etched extensions to the sides

    And back together again.


    And a broadside view showing the all the recent additions.

    Last edited: 7 July 2018
  2. P A D

    P A D Western Thunderer

    Here's the bogie frames tabbed together before soldering. The formost of the spacers has a slot for the slider. I did not realise until much later, but it would be best to remove the cusp from the a slot in the flat, to ensure the runs smoothly.

    After soldering , adding the rod spacers and end castings and cleaning up.

    After adding the axle box castings, I discovered that the holes in the frames, the equalising beams and springs were all at different centres.

    To rectify this I first added the inner equalising beams, wedged them in place with strips of card and then soldered to the axle boxes. Then I drilled fresh holes in the frames, throuth the holes in the beams. This allowed me to add the rods to mount the springs and outer beams.

    To correct the hole centres in the springs, I opened the holes from the outside with a razor saw and file, to make them into slots. This allowed me to fit them over the wider spaced rods.

    Here is the spring after slotting the holes.

    After finishing and cleaning up.

    And with the wheels on. 20180709_210836.jpg

    Here's the bolster casting after fitting the grease lubricator. The etching just has half etched holes, so I drilled them out and fitted 0.5mm brass rod to represent the grease nipples. 20180709_210808.jpg

    And after fitting to the bogie. The pivot has also been added.

    And fitted to the chassis.

    This is the mounting point on the chassis.

    And from the topside. 20180709_220646.jpg

    And with the body on.


    Attached Files:

    Last edited: 10 July 2018
  3. P A D

    P A D Western Thunderer

    To finish off the bogie, the side control springs have been fitted to the slider. 20180710_230740.jpg

    The bogie is attached to the frames with a spring over the pivot that sits in the large bush in the rear spacer. It is retained with a C clip. The rear coupling hook can pivot from side to side via a 12 BA screw through the mounting point 20180710_202219.jpg
    Here's a view from the rear.

    Next the pony truck. After adding the coil springs to the bearing/side frames, I soldered these to the bottom etched A frame. I was then able to use this assembly as a jig to line uo and solder the two halves of the bolster.

    And after soldering the bolster to the side frames.

    And with the remaining parts added.

    A view from the underside.

    And with the wheels on. 20180710_184029.jpg

    Mounting to the chassis is via a bracket and 12 BA screws.

    Here's a view of from the front with the body on.

    And a couple of the complete loco.

    Starting to look the part now.

  4. P A D

    P A D Western Thunderer

    I noted in the front view that the guard irons were over hanging the rails when fixed as per the instructions. The wheel rims were also just touching the bolt detail so a correction was needed.
    After removing the irons, I filed out the half etch location to make a slot. Here's the right hand one after filing. 20180711_104750.jpg

    After refitting the irons, they no longer touch the wheels and are now in line with the rails. Just goes to show, that with this error and the missaligned holes in the bogie equalising beams, no kit is perfect. That said, they were easy issues to correct, so no complaints.



    Attached Files:

  5. P A D

    P A D Western Thunderer

    Next the cylinders. Two cast blocks with etched overlays for the wrappers. After fettling them up, the holes for the mounting screws need to drilled out and tapped 10BA. Here they are ready for the wrappers to go on.

    As per the instructions, I soldered the top edge first and the folder the wrapper around the block down to the bottom. To start with I held the block in the vice and lined up and clamped the wrapper with a suture clip.

    Here they are with the wrappers on and the inspection covers being fitted. I scribed a fine vertical and horizontal line and added masking tap to butt the cover against for soldering.

    This is the left hand cylinder after fitting the core plugs, snifting valve and cleaning up. Looks like there's a slight gap in the solder along the top edged of the inspection plate, that needs attention. These brass castings are excellent, but a real pain when they need drilling. In the case of the cylinders, that's 10 holes each side. Two for the screws, two for the core plugs, two for the lubricator pipes behind the core plugs, one for the snifting valve and three for the cylinder drains.

    Here's the right hand cylinder screwed to the frame.

    And from the front with both cylinders on. It's just possible to get a screwdriver into the slots in the screws and turn it.

    Here it is assembled again.

    There are not many etched parts left now but still bags of castings.

    mswjr, Rob Pulham, farnetti and 7 others like this.
  6. markjj

    markjj Western Thunderer

    Watch your wheels don't touch on the back of the front step it's a common problem if you have tight curves.
  7. dibateg

    dibateg Western Thunderer

    Your work is so tidy Peter... Note to self - must do better!
    simond and 3 LINK like this.
  8. P A D

    P A D Western Thunderer

    Thanks Mark.
    Strangely, on the left hand side, the wheel just clears the step on the curves, but on the right side it just catches. I cannot for the life of me see why that might be as everything is square. I think the simplest thing to do is to move the pivot casting on the apex of the A frame forward slightly, which will move the wheels back to clear both steps. I could try take the steps off and move them forward, but then then they would be noticeably too near the buffer beam and it will also be more difficult.

    Many thanks Tony.

    I don't have to build to a deadline, so I can spend longer cleaning up. Whether that ultimately has any impact on the model after finishing is debatable, but it is how I prefer to do it. Do you recall having any issue with the pony wheels touching the steps on your build?

  9. markjj

    markjj Western Thunderer

    A guy at my local area group had the same problem running it on our club layout. It took ages and about 20 people watching it's every move to find the short. I think he just tweaked the step out very slightly I think Slaters thick wheel rims don't help.
  10. dibateg

    dibateg Western Thunderer

    No I don't recall a problem Peter - but there again - my memory. I'm recall it ran ok on Heyside ( 6 foot radius curves ) ok.

  11. P A D

    P A D Western Thunderer

    Thanks Tony,
    I adjusted the pivot bearing slightly and now the pony swings clear of both steps.
  12. P A D

    P A D Western Thunderer

    Here's the pivot bearing after removal. I have a round file the same diameter as the bearing hole, so it was a simple matter to file the slot to move the bearing forward slightly.
    And refitted.

    Now the wheel just clear the step.

    After having fitted the roof vents earlier, I noticed the two etched overlays that are not mentioned in the instructions. Also looking closer at the illustration, I realised that i had fitted them upside down.

    After removing and straightening the vents, I then laminated the overlays, curved to the shape of the roof and refitted. The one with the row of rivets goes to the front, although I have seen a picture of one preserved example where they are the other way round.

    And back in place on the cab.

    Next I turned my attention to the buffers. These are the parts minus the spring ready for assembly. Top left is the steel shank and etched retaining disc, that fits into the shank, with the lugs in the slot. This has to be soldered in place and the lugs filed flush. To the right is the cast buffer head and below is the stock. The dimple in the side has to be drilled through, as does the one on the other side. After fitting the spring and the shank, a piece of rod is pushed through the hole and the slot in the shank to retain it. The rod is filed flush and the tiny riveted discs are glued over the holes. 20180712_174527.jpg

    Here we have the heads and shanks assembled. One buffer is complete albeit temporarily.

    Here are the rear buffers added to the beam. 20180712_174303.jpg

    And front ones. It makes things really easy to do when you have sub assemblies like this. There are a number or other parts to go on this before it is soldered to the smoke box.

    I couldn't resist a preview with the heads placed in the stocks.



    Attached Files:

    Pencarrow, Len Cattley, cmax and 17 others like this.
  13. P A D

    P A D Western Thunderer

    The cab floor is designed to be fitted from below via two tabs at the front locating into slots in the cab front. It is supposed to be soldered but it clearly offers the opportunity to have it removable. To facilitate this I drilled and tapped a hole 10BA just behind the floor opening. A
    simple pivoting bar is then swung under the rear of the floor to retain it.


    The floor then slots in, the bar is swung in position and the screw tightened. There is just enough thickness in the metal to take the thread, but a better option would be to solder a nut on the other side earlier on.

    After that I turned my attention to the tank top details. The kit provides alternative castings for the water filler and inspection plate, one type cast and one type etched laminates for the latter.
    For the fillers I've gone with the screw locking type as soured to early LM locos and fire the inspection plates I used the cast ones. These are a bit on the thick side so a fair bit of rubbing down was needed to thin them down. The etched bases for the tank retaining brackets, lifting hooks and fire iron holders were also fitted. The instructions suggest fitting the breather vents later on to avoid the risk of knocking them up during handling, but they are secured with two lugs into holes in the tank tops plus a tab on the inside of the tank. I decided they would be robust enough so fitted them now while it is easier to do and clean up.

    And a view from the other side. The two small holes behind the inspection cover on the left hand tank are superfluous and will be filled.

    Here are some shots with the boiler and firebox back in.
    20180713_184519.jpg 20180713_184412.jpg 20180713_184454.jpg

    And a couple of the complete loco.
    20180713_184039.jpg 20180713_184107.jpg

    I wonder how Farnetti is getting on with his, over on the "What's on your Workbench" thread in the members forum. Last time he posted he was ahead of me, but I may have caught him up.
  14. farnetti

    farnetti Western Thunderer

    Have been away for a couple of weeks and so not much so you getting slightly ahead of me. I have been wondering what those two half etched plates were for, I'll be putting them on the roof today.

    I have been having trouble holding the wheels firmly to the axles, the screw, although tight, is still proud of the wheel boss. Mine are from the S& stores rather than Slaters,, investigation needed. I also bought the additional crankpin set from MOK which involves drilling out the crankpin holes on the wheels and counter sinking them on the rear. Another job for today, hopefully enough time to finish the cylinders as well.

  15. P A D

    P A D Western Thunderer

    Hi Ken,
    It will be interesting to see if any more "mystery" parts turn up. :)

    Can you clarify who's wheels are you using, as I don't recognise the name. Other than cast wheels, I was not aware there was another supplier of 7mm wheels.
  16. richard carr

    richard carr Western Thunderer


    The problem with the wheels is that the screw doesn't seat properly, I have the same problem on the S7 stores diesel wheels.

    So 2 things you may need to do, shorten the screws and thin the neck of the where it starts to flare out, that has cured it witht he diesel wheels.

  17. Dog Star

    Dog Star Western Thunderer

    Advice received from David White... ensure that there is no swarm or dirt at the bottom of the threaded hole in the axle.
  18. farnetti

    farnetti Western Thunderer

    Thanks Peter, Richard and Graham. The wheels are Slaters but via S7 stores. There is plenty of depth in the axle for the screws and I have just solved the problem by slightly counter sinking the ends of the axles.

    So on to the cab roof and crankpins. When the wheels are back in place I'll fit the brake gear and post some more photos then.

  19. markjj

    markjj Western Thunderer

    I have both S7 and finescale wheels I believe the S7 ones are possibly slightly thinner I don't think the ends of the axles where adjusted to compensate for it.
    farnetti likes this.
  20. P A D

    P A D Western Thunderer

    I assume you blokes are talking about re-profiled Slaters wheels for scale 7? You don't have these problems if you stick with narrow gauge! :)

    I've been pressing on with the detail on the front footplate, boiler and tank tops, as I want to get as much on as possible before soldering the three units together. Here are the front sand fillers and mechanical lubricators. The holes for the piping is only marked with indents on one side so the other side needs scribing and marking before drilling. The ratchet cover on the front is not provided so I knocked something up from the spared box. the cast handles are provided.

    The holes for the linkage to pass through the running plate are ready etched, but those for the piping need drilling/filing out. The etched base plates for the steam pipes is also added.

    A view from the front.
    And from the rear.

    Next the oil pots on the frames - two feed on the left. 20180717_194831.jpg
    Three feed on the right.

    The regulator linkage.
    And water valve on the firebox side.

    The front lamp brackets and smoke box door handles are now added although the smoke box front can still be removed. I made the handrails for the smoke box/boiler but again, the rails and knobs are soldered, but the knobs are just pushed into the holes for now and can be separated.
    There are some brackets to go on the top inner edge of the left hand tank top, for pipework, but once they are on, I think I'll be ready to solder up the main body, fire box, boiler and front running plate. Then back to the chassis.