7mm Jan's 7mm Workbench

Discussion in 'Area 51' started by Lyndhurstman, 1 May 2017.

  1. jonte

    jonte Western Thunderer

    I see. Now it all makes perfect sense, Jan.

    Apologies for being painfully slow on the uptake ;)


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  2. Lyndhurstman

    Lyndhurstman Western Thunderer

    Slot Machinations

    Fitting the coupling plate was proving problematic. Until I realised the scalpel could aid location of the two slots. Both components were tinned (thinly) with solder paint before being introduced to the iron. It all seems to have gone well. Next up; the spring stops.

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  3. auld_boot

    auld_boot Western Thunderer

    Not sure if its good practice but I find cocktail sticks are handy for this type of thing.
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  4. AJC

    AJC Western Thunderer

    Ditto - they certainly work, they leave little or no residue, ergo, it's good practise and saves my fingers. While this is all very nice to see, when are you coming back to the proper sized stuff Jan? ;)

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  5. Lyndhurstman

    Lyndhurstman Western Thunderer

    Hi Chaps,

    Yes.. indeed. Cocktail sticks are very useful - and have the advantage of being whittleable (made up word?). But sadly, my last was being used as a solder paint dab applicator. And the scalpel blade gives a surgical air to my hamfisted approach!

    @AJC Hi Adam. Ah... the proper sized stuff. Having enjoyed the return to engineering offered by this build, I'm toying with excavating Ian Macdonald's etched brass BR Flatrol MVV diagram 2/512 - Kitbuilding & Scratchbuilding for something a bit different...


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  6. Lyndhurstman

    Lyndhurstman Western Thunderer

    When Summer Starts...

    Spring Stops
    Four fiddly fold-ups finally fitted.
    The fret has spares - which eases the fear somewhat. Thankfully, I didn't need them. They fit in some half-etched cuts in the bottom of the solebar, and the ends of the feet needed a bit of filing to make them fit. Again, both parts were tinned and fluxed. I'm getting the hang of this...

    Next up, that well known harridan of airfields everywhere - Vee Hangers.
  7. jonte

    jonte Western Thunderer

    Neat, man.

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  8. Lyndhurstman

    Lyndhurstman Western Thunderer

    Bearing Down
    Progress has stalled of late. Partly due to work-devolved fatigue and apathy, partly due to my energies being required elsewhere. Another brake on proceedings can be seen below:
    This is the trial fit of a Slaters bearing in a PMK axlebox casting. This is but one, when subsequent investigation revealed my disappointment was to be fourfold.

    The Slaters bearings are long and thin, and fit short stub axles on the wheelsets.
    Thus, the holes to take them have to be deep and thin, and - in this instance at least - appears to have been skewed off central. A 2.6mm drill was therefore purchased from Eileen's (usual speedy service), and the holes re-aligned using pin vice and wrist action. This was 75 percent successful; one casting was opened to atmosphere due to a flaw in my monitoring regime.

    I have now stopped, as the work involved in aligning four axleboxes in perfect alignment is not matched by my current levels of self-confidence. I hope this block is only of stumbling height, and not the foot of the cliff it currently feels like.


    Attached Files:

    Last edited: 24 June 2017
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  9. jonte

    jonte Western Thunderer

    Damn you twenty five per cent!

    I feel your pain, Jan.

    If I humbly suggested using that green coloured modelling putty that's bar-of-rock-shaped to plug the void in the atmosphere and then re-drill, would that be teaching my granny to suck eggs, or just confirm that I have absolutely no idea what I'm talking about :( ?

    Keep on keeping on, Jan ;)

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  10. Lyndhurstman

    Lyndhurstman Western Thunderer

    Hi Jonte,

    Thanks. I have some Squadron White (last used to defend Ian Smith in Rhodesia, I think) that I intend to insert. The tricksy nature of the comfit means that the axleboxes and wheelsets have to fitted as one unit. Which means everything has to be square at one hit. The instructions are a bit ridiculous here, I think:

    Tack solder two axleguards to one solebar. Fit wheelsets and second set of axleguards to other solebar. (check axles are parallel). Place on a flat surface and adjust until wagon sits without rocking. Solder solid.

    The penultimate sentence is a précis of horror, I think. What I need is the 7mm equivalent of the 4mm Brassmasters wheelbase setting jig, I think. But that means more expense, and there are other priorities to factor in.


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  11. Rob Pulham

    Rob Pulham Western Thunderer

    Hi Jan,

    The Brassmasters jig is well worth having for times like these.
    Rather than use squadron Putty (or any other 'filler') I would suggest using some low melt solder to fill, the hole and then file it back.

    Worst case give Jim a call and ask if you can buy another casting he is usually very accommodating.
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  12. Lyndhurstman

    Lyndhurstman Western Thunderer

    Hi Rob,

    Thanks for your input - very much appreciated.

    I may well try the low melt option. And thanks for the tip about ringing Jim; I must admit I never thought of exploring that route.


  13. Lyndhurstman

    Lyndhurstman Western Thunderer

    The Jig is Up
    An evenings work with vernier, plasticard and plasticweld have resulted in this:
    I suppose you could call it a cheapskate.
    Really, it's nothing more than some bunds to retain the axles at 56mm pitch (handy, those pinpoint ends...). A few settled scores with the skrawker gave the rectangle - sized to be a tight 'go' fit against the back of wheel rims, and a raid of the Plastruct forest found some 60 Thou square section to provide a parallel position. I may (Not now, Theresa) put the fourth strip in. Or I may not.

    You'll note that the rustic curse I carry has come to visit. Best get to cleaning pronto (cousin of Tonto). I wish there was a cure - I can't get on with surgical gloves...

    Last edited: 26 June 2017
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  14. mickoo

    mickoo Western Thunderer

    Blacken the wheels and axles as soon they come out of the packet and then lightly oil. I use a cotton bud and just wipe the surfaces. You can do the same without blackening but be aware, with either option, that when you touch them you will get some on your fingers which can be transposed to your other work. You just have to be a bit more methodical and clean your hands after touching them.

    Another option is a wipe with WD 40 anything really to give a thin barrier to the atmosphere and it only needs to be a real thin layer.

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  15. Lyndhurstman

    Lyndhurstman Western Thunderer

    Thanks @mickoo
    It was late when I spotted it, so I'll give it a go tonight. I have some Carr's Blackening Fluid. Somewhere (my partners book collection has been 'temporarily' relocated to The Tiny Train Room, and now forms a bibliographic barrier of some density!)

  16. mickoo

    mickoo Western Thunderer

    It's the oiling that seems to be the important part, blackening helps but I've had that rust through when I haven't oiled them or have handled them a lot afterward and then not re oiled. Any oil will do (6000 mile sump oil isn't preferred;)), I've even used kitchen cooking oil as a trial with no ill effects, anything to give a thin barrier against the atmosphere. You just need the thinnest smear to work, as I said above, I use a cotton bud and then wipe it all with tissue paper so it's just a hint of a smear.

    I oil mine the second they are fully dry after blackening, make sure they are completely dry then oil right away.

    It will collect dust or dirt over time, but a simple wipe gets rid of that and that's easier than having to scrape or mechanically clean all of the rust off later.

    If you're not going to handle them much, then spraying the axles in matt varnish once blackened will help preserve that part, especially as you're using outside bearings.

    Last edited: 27 June 2017
  17. Lyndhurstman

    Lyndhurstman Western Thunderer

    ....another Empire backfire
    Things have gone a bit retrograde (it's like Lucozade, without the fizz). Having spent an evening believing I had found The Truth & The Way with my home-brewed alignment jig, its accuracy led me to the conclusion that there was no way I could provide alignment between the four axlebox/W iron castings, and have parallel axles.

    I spent a considerable time in the dumps (some people call it Liskeard), and considered consignment to the Big Box Of Failures ( the kit that is - I have been there long enough to qualify for voting rights). But I thought I'd try one more time (it's amazing what strange motivations a very crap day at work will provide).

    There had to be a reason for the error, and I think I've found it.

    Having eased off the castings (superglue is a wonderful thing) I checked the position of the spring bumpers using the jig and wheels as a gauge. The non-alignment of the stub axles over one of the bumpers indicated one bumper was about 0.75 mm out of position.
    It doesn't sound a lot, but unlike the single injection moulded assembly I'm used to, in the kit, it's a key relationship. Because the castings are separate to the etched solebars. The buffer beams and solebars are separate. But the wheels and castings are effectively a single unit, and anchored by the wheelbase. So any error in build, any slackness in squareness or fit, any incorrect placement of parts, will explode in your face. Which is what happened here. There are half-etch location holes, and I thought I'd done it right first time, but the combination of fiddleness and wielding the iron meant I didn't spot the movement out of position.

    So it was our with the 40W Antex, the 2" V block (heatsink!) and some 188 solder. Now things are a lot better.
    I think we're back on track (even if we have our wheels up).


  18. jonte

    jonte Western Thunderer

    Well done, Jan.

    I admire your spider-like tenacity (and, as usual, your ingenuity).

    If it has been me, I'd have finished the post '..... consignment to the Big Box of Failures.'

    Best wishes,

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  19. Lyndhurstman

    Lyndhurstman Western Thunderer

    Thanks, Chum

    Spider-like? I'm mostly armless. My ingenuity is but a sniff compared to the full draught of yours.

    The BBOF was lurking. It was close. Very close!


    Last edited: 30 June 2017
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  20. Rob Pulham

    Rob Pulham Western Thunderer

    Hi Jan,

    I am glad it came right in the end, these things happen and sometimes you just need to be in the right mood to solve the problem. Other times you need to put it aside before you do something irretrievable.

    Having spent some time on Wednesday night fitting the brake gear on the B16 Which involved shortening a part and making a forked end to it. This morning I discovered by chance a photo that clearly shows how the brake gear should fit and I now need to make the shortened part back to it's original length and fit the bit's that I missed.