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

    Based on Martin Shaws comments regarding the controls for the water valves, I have replaced the "bakelite " type handles with some spare etched hand wheels. As Martin mentions, the generic BR backplate drawing shows these type of fittings, albeit on brackets extended from the back plate, as the drawing is representative of a tender loco with the water valves outside of the cab. I think it's fair to assume that the tank locos would have had the same fittings.
    Here's the back plate after changing the controls. 20180929_182629.jpg
    They are visible through the cab windows so worth getting them right 20180929_182413.jpg

    I can also add the missing control rod and handle for the injectors either on a bracket or in the hole in the splasher seen here through the cab lookout.

    Apart from adding the buffer heads that just leaves the side window frames to fit after painting. I will need to source some couplings also as apart from the pivoting rear couplings hook, these are strangely not included in the kit.

    And some gratuitous shots to finish off the post.
    20180929_182230.jpg 20180929_182135.jpg 20180929_182316.jpg 20180929_182028.jpg
  2. P A D

    P A D Western Thunderer

    As all the soldering is now done, I won't need to wash the loco again before painting, so to finish things off I have added the buffer heads. I'll mask them up for spraying.

    I had it running on the rollers for some time today and then gave it a run on my brother's railway.


    Just out of interest I checked the cab of my brother's DJB 4MT that I built some years ago. The handles for the water valves are the 4 spoke wheel type with a peg, albeit that are bracketed off the back plate as on the tender locos with the valves out side the cab.
  3. markjj

    markjj Western Thunderer

    If you search on YouTube for "BR Standard Class 4 2-6-4 cab ride". There are several videos of the different preserved loco's all of them that I have watched have the handwheels with the peg on. I hope this helps. Thank you for your excellent thread to it's been a pleasure following it you have done an amazing job.
  4. P A D

    P A D Western Thunderer

    Thanks Mark.

    I'm convinced that the 4 spoke wheel plus peg is correct, and this plus other preservation images, coupled with the BR Standard cab layout diagram, just reinforce it for me. Thanks again to Martin Shaw for the heads up. Comments like his are always welcome.

    mswjr likes this.
  5. Martin Shaw

    Martin Shaw Western Thunderer

    Your more than welcome, it is a fine fine model. Pondering on this handle issue, which incidentally is for live steam to the injectors not water, some things come to mind. 80002 which the kit is based on is alone amongst the preserved Std 4s as not built at Brighton but Derby, and was also bought direct from BR so presumably arrived at the KWVR with all it's non ferrous fittings intact. I wonder whether the original intention was to use the teflon type single handle until early experience showed them not up to the treatment they received in service, they split if hit too hard, and the brass handwheel substituted. It's possible.
  6. P A D

    P A D Western Thunderer

    Hi Martin,
    You mention Teflon handles. I assume you mean Bakelite as mentioned earlier. Certainly this material being quite brittle would not survive a swift blow from a hammer. Your alternative scenario may be correct, but I'm more inclined to think that in general the 4 spoke hand wheel with peg was the norm. That said, it does beg the question why the preservationists would fit the Bakelite handles after purchase, when one assumes the loco was purchased intact.

    A further detail that I have noted that is not catered for in the kit, is a mud hole and clamp in the lower firebox near the sandbox. One assumes the small plate fixed to the frames was to deflect the sludge away from the sandbox??? There is also a wash out plugs to the right and higher up. The frames in the kit have both holes, but nothing behind to represent the firebox, so that will be added first.

    Rob Pulham likes this.
  7. Martin Shaw

    Martin Shaw Western Thunderer

    I wrote Teflon when I really meant Tufnol, how silly, either way I'm not convinced about Bakelite which in retrospect would be too brittle. The deflector plate by the mudhole door is I think meant to divert spray from the wheel away from the sandbox rather than a mitigation during boiler washouts. I have fired off an email to the KWVR loco department to see whether they can shed any light on the matter, I'll let you know in due course, although I do agree with your surmise.
  8. P A D

    P A D Western Thunderer

    Hi Cliff,
    I've been meaning to say, why don't you write it up on here any way. It would certainly be interesting to me and I'm sure many others. Be even better if you have more photos than were in the Gazzette article. Builds of that quality are timeless and as the kit is available again, very relevant. Just a thought.
    Cliff Williams likes this.
  9. Cliff Williams

    Cliff Williams Western Thunderer

    Hi Peter
    You are probably right, more pics can be taken to help others, it’s been a scary sixteen years since the Gazette and thirteen since the RM article, an update might be in order.
    The cameras are much better these days too!

    Will get on it.
    Pencarrow, Len Cattley and Rob Pulham like this.
  10. Peter

    Fantastic thread, am in the process of building the MOK 4MT tank, only my second kit with outside motion, the first was the JLRT WD 2-8-0, got there in the end but quiet a shock after several of their diesels, and Jim McGowens brass kits. Anyway less said the better. Still busy with the chassis of the 4MT, and picked up on your comments about cleaning, not my strongest suit, but would love to get a pre-paint finish something nearer to your standard than my previous efforts. You mention various tools some of which I have, the wire brush you mention I assume fits a rotary tool like a Dremel, where can I get the brushes, how many are you likely to go through with a kit? Also the viakil do you spray on full strength or do you dilute and use to wash the work at the end of each session, so far my chassis is not too bad, as most soldering is inside. Do products like that have adverse effects on Slaters wheels? Excuse all the string of questions but the kit isn’t cheap and one wrong choice could be an expensive mistake
    Dog Star likes this.
  11. P A D

    P A D Western Thunderer

    Hi Old Sailor,
    Yes, the wire brushes are used in the mini drill. Depending on the quality depends how long they last. Proxxon are the most expensive but If you look on eBay you can find cheap sets with all three types of brush, flat disc, cup and straight. These are the best value. If you search "45pcs Stainless Steel Wire Cup Mix Brush Set Fits For Dremel Rotary Tool Set/Kit" you will find them on eBay for about £6. Yes that's 6 quid for 15 of each type! They bristles do tend to fly off so be careful when using and do it under a cover if possible to contain where they fly. It goes without saying that you need to be careful that you don't knock of or damage fragile parts with the brush, and some areas are simply not accessible. Then it's down to scrapers, chisel or scratch brush. Off course it's best not to use exess solder in the first place. Sometimes I get it right and sometimes I wonder if I've ever used a soldering iron before.

    I wash the workpiece regularly in warm water and cheapo washing up liquid, then dry with an old hairdryer. Make sure its dry before using spinning brushes or it will make dark stains. Periodically I spray with neat Viakal and then brush with an old tooth brush or stiff cheapo artists brush. Don't leave it on the metal to dry or it will stain, at least on brass. I know because I screwed up and answered the phone and left it too long before rinsing . Rinse very well while brushing to get into all the nooks and crannies. For wet/chemical cleaning I always remove any ferrous parts, so wheels, etc from the chassis and buffer heads from the body.

    Scrubbing with hob bright or something similar is also very effective, but needs very thorough rinsing to get rid of the residue. It clings to solder so even fine seams of solder show up white.

    Hope that helps, but if you need anything else, ask away.
  12. Thanks Peter, the tips give me a good starting point, know what you mean about soldering, sometimes I actually think the result is about as good as it gets and at others wonder if I used a tar brush!
    One thing I really want to get right is all the motion parts, plus I’m toying with the idea I might get it professionally lined out, even painted, but that’s a discussion for another day.
    Last edited: 27 October 2018
    P A D likes this.
  13. Peter

    Just out of interest, the pipe jointing unions you fabricated, how did you construct them, they look very good and certainly add to the overall finish?
  14. P A D

    P A D Western Thunderer

    I'm not sure to which unions you are referring. If you can point me to a picture on the thread or download and repost, I'll be happy to explain.
  15. This one, also the ones on the stream pipes.

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  16. P A D

    P A D Western Thunderer

    I used micro bore tube that you can pick up from most model shops and M0.6 hex nuts from prime miniatures.

    Brass | Prime-Miniatures

    Cut a short length of tube with a sharp craft knife by rolling the tube on the cutting mat with the blade in contact. Don't press too hard or you can crush the tube. As you roll it will score the tube and cut the required length. Be careful as when the cut happens, the tiny length of tube can ping off into the carpet void or other such areas that swallow small parts. You can get lengths of about 1mm but it's hard to get them consistent, but mostly that does not matter. Put a length of wire through the tube, add a nut to each end and solder. For the T joint you need to hold the first union in the vice and drill a 0.4 mm hole. This is where the swearing can start when you either break the drill or bugger up the first part. Assuming success with the hole, line up the wire, next bit of tube and nut, and solder. Easier said than done but I hope that helps .

  17. simond

    simond Western Thunderer

    Put a scrap bit of wire through the tube before cutting it. It starves the carpet monster.

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  18. Dog Star

    Dog Star Western Thunderer

    I appreciate that this subject has been aired before and I apoligise for returning to the matter - I do so because I think that the answer to the original question might have obscured what is going on with the lubrication of the piston rod. If you are interested in the design of the BR 4MT or enjoy a trip down a research rabbit hole then please refresh your memories of these posts,

    I start with a post from Dave (@daifly) which refers to the original question that was raised by Ken (@farnetti):-

    7mm - MOK BR Standard 4MT Tank

    Noting that the subject of Dave's post above is the single feed oil box which is mounted on the rear stuufing box of the cylinder, now find a comparable view in this post by Peter (@P A D).

    7mm - MOK BR Standard 4MT Tank

    Of immediate interest is that the two photos appear to show different styles of oil box... points to note are (a) the relative position of the box to the slide bar, probably due to the shape/size of the support bracket and (b) the way in which the lubrication pipe is connected to the oil box (in one photo the pipe exits the box at right angles with a typical union connection and in the other photo there appears to be a pipe connection through the support bracket into a lug cast on the bottom of the oil box. If the photos do show different styles of oil box then is that difference a reflection of life in BR times or a consequence of preserationists having to make do with what is available. From our point of view, Jeanpaul (@lnerjp) can you offer a photo of the fitting on 80136?

    Given that the visible oil box is gravity feed then I feel certain that the outlet from the box is drip feeding onto the piston rod as is visible in one of Peter's photos (in his build topic on the MOK BR 4MT).

    Now to a discussion point in Peter's topic which I think was not answered. There is a small bore copper pipe, maybe 1/4" or 3/8" OD, which loops over the top slidebar adjacent to the oil box and might, from what is visible in one of the photos (see link above), be the oil pipe which drips onto the piston rod. I suggest that the oil pipe which is making the tortuous journey over the top slidebar is associated with lubricating the piston rod within the stuffing box. In this post from Martin (@Martin Shaw) there are a few photos which show the rear cylinder cover after the slidebars have been removed:-

    BR 4MT 2-6-4T - resource material

    Adjacent to the stuffing box is an "orange" washer over a dingy recess - most likely this is fresh rust on a machined surface which has been revealed by the removal of an union. I believe that the "loopy" pipe in the previous paragraph terminates on the (missing) union. As to why there is an oil feed into the interior of the stuffing box - I admit that I do not know. GWR locomotives used graphited asbestos for packing the stuffing box... I recall being told that other companies used metallic packing for some classes. Might the BR 4MT use metallic packing rings for the piston rod and hence the "loopy" pipe to feed oil direct to the packing (does that imply that the oil feel is under pressure?).

    I hope that either Martin or Jeanpaul can help with details of the purpose of this pipe.

    thank you and regards, Graham
    Last edited: 8 November 2018
  19. P A D

    P A D Western Thunderer

    Hi Graham,
    Interesting points you raise. I can see that I will have to drag my bones up to Oxenhope some time soon and take a closer look at this area on 80002.
  20. Martin Shaw

    Martin Shaw Western Thunderer

    BR std locos use metallic packing, certainly for the piston rod, and I think so for the valve spindle. There isn't really a sensible reason why not. I'll reiterate a comment I made earlier in this thread, 80002 was built at Derby and was bought direct from BR service so is probably nearest to the original, notwithstanding that 50 odd years have now passed and it's owners may well have changed things around for whatever reason. All the remaining extant ones were built at Brighton and passed to their current owners via Barry largely bereft of non-ferrous fittings. I would guess that the oilbox that feeds the piston rod will be to an original design in some cases and a variant in others, which is most correct I don't know, If I can access the drawings I will.
    The pipe that feeds into the rear cylinder cover is as you surmise, under pressure and certainly seems to feed the packing directly, or possibly the inside surface of the piston rod such that reciprocating motion takes oil to the inside of the packing and the exterior oil box just ensures that the outer edge of the packing is lubricated. I'm at the railway tomorrow so I'll ask a sage gentleman.
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