Crymlyn A Shop Techniques.

Discussion in 'Workbenches, including workshop techniques.' started by davey4270, 23 October 2020.

  1. Brian McKenzie

    Brian McKenzie Western Thunderer

    Did the foreman go to the dogs with Parry the Pipe?
    Either Dai Larfin, the stores person has issued an oversized hole for the piston rod or Owen the Spanners was too busy ogling the girls from the local leisure centre when stuffing up the gland box!
     
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  2. davey4270

    davey4270 Western Thunderer

    It was the same size as the etched hole in the cylinder casting although it is larger than the piston rod.
     
  3. davey4270

    davey4270 Western Thunderer

    28. Crank Pin Bushes and Brake Linkages.

    The standard Slater’s crank pin bush will need to be shortened. More by luck than judgement I found that 10 thou, about 0.3mm play suffices. The pictures hopefully explain:


    IMG_2407.jpg
    Centre in the picture is the standard Slater’s crank pin bush while to the left is a shortened specimen. This is quite easily done by placing a piece of Plasticard drilled to the diameter of the bush, 2.5mm, and slipped onto the bush. Place the relevant coupling rod over the bush with the outside face down against the plastic, you don’t want to damage the face. Gently file off the excess until it is flush with the back of the coupling rod, the Plasticard giving the required clearance, and clean up. The set up is shown in the right of the picture. Use the correct coupling rod for each bush as there will be slight differences in thickness. You did remember to mark each one didn’t you? [​IMG]


    IMG_2408.jpg
    The next job is to fit some brake pull rods. Unfortunately all my hard work soldering the brake hangers at a measured spacing from the wheels became loose when handling the frames so next time I’ll just solder them approximately in position. [​IMG].
    I reassembled the wheel sets and trimmed the leading set’s crank pins to clear the inside of the slide bars. Don’t worry about obtaining extra clearance here as this will be dealt with later.
    The brake cross bar, just above the rear sandboxes in the picture, had the two cranks threaded on and was soldered to the frames leaving the cranks loose for the moment. To each crank I soldered a length of rod long enough to just pass the leading brake hanger cross bar. I made a slight kink in the rods just over the rear axle so that the rods rest on the 3 hanger cross bars. Position the pull rods just inboard of the sliding horn blocks and adjust the brake shoe’s position relative to the wheel. When happy, solder the rods together. I positioned the pull rods to allow the horn blocks to be removed. Straighten the pull rods cranks and solder in position.


    IMG_2409.jpg
    The model is taking shape and looks the part with its wheels fitted. The chimney is posed for the picture. There’s still a phenomenal amount of detail to add without the electrics and painting. Nobody has yet hazarded a guess to its prototype.
     
  4. davey4270

    davey4270 Western Thunderer

    29. Steps and Drain Cocks.

    Once again we’re back to the fiddling bits, the things you shouldn’t put off or they’ll never get done. As an early version of an early kit, I think that’s right, the model was a tad spartan in the cylinder drain cock department. As always, more captions with the pictures:


    IMG_2410.jpg
    I was fortunate in having 4 spare drain cocks amongst my box of unused castings. It was simply a matter of marking out where to drill the locating holes. This was under the cylinder along the centre line of the end cover plate, the kit is designed to have the slide bars set further out to accommodate the crank pins with Finescale tolerances, and spaced apart by the drain cock operating bar. I tied a piece of white cotton, about 6 inches, to each drain cock before removing it from the sprue. This will give you a sporting chance if finding it before the carpet monster eats it. I tinned the spigot with an atomic sized piece of solder, flux on the hole, and press in with a hot soldering iron pressing on the drain cocks flange. Repeat three times.
    Remove the drain cock operating bar, a spot of flux where it touches each cock and the bottom of the cylinder wrapper and make each joint with a dot of solder on your hot iron.


    IMG_2414.jpg
    A minor disaster with fitting the first step, I mistakenly thought that I could solder it with my normal 145’. In this I was reasonably successful or so iI thought but the heat had allowed the bottom slide bar to move undoing all my work on free movement of the cross head. I then had to adjust the slide bar and, you’ve guessed it, the carefully positioned step fell off!
    Ok then, low melt it is. Low melt solder won’t stick to brass or nickel silver but will stick to solder. You have to put no more than a stain of ordinary solder where you want to place the step, I then put a blob of low melt flux on the “solder stain” where the step is to be positioned, position the step, cut off a minute slither of low melt solder and touch the solder with my normal iron for literally 1 second. If it doesn’t melt try again for another second. The solder will melt and be sucked under the step by the flux. At 70’ the low melt didn’t disturb the 145’ holding the slide bars. It will take about 10 seconds to set so be patient. The molten solder is shiny and turns dull as it sets. Another snag is that the steps are horizontal and the bracket is slightly off vertical. You can allow for this with the angle where the step fits to the slide bar support bracket. The right hand bracket had only one stop.


    IMG_2413.jpg
    While the left hand side had two. I must remember not to use really hot water when I clean up the model.
     
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  5. davey4270

    davey4270 Western Thunderer

    30. Sand Pipes and Buffer Plank Brackets.

    A couple of hours work today saw the fitting of the rear sand pipes and buffer plank bracing brackets.
    Once again, more captions with the pictures:


    IMG_2417 (1).jpg
    This kit had fold up rear sand boxes instead of cast items. I have found that the sand pipes often work loose on my models in service so I came up with the idea of drilling a similar hole at the top with the wire passing through and being soldered at the top as well as the bottom. A brass washer could be slipped over the wire on the top to represent a filler cap. I decided not to fit this here for two reasons, firstly there would be little room above the sand box for the top wiper pickups to be fitted and secondly it wouldn’t be visible underneath the footplate anyway. Difficult access was probably the reason why they were moved into the cab at a later date!


    IMG_2420.jpg
    One of the rear buffer plank bracing brackets soldered in place. The instructions give you the option of soldering to either the frames or the buffer plank. I chose to solder them to the frames as this would give some sideways adjustment to the chassis fit. The picture shows the hand brake rod on the driver’s side which needs to be removed, there were 2 the same, although I’m sure a vacuum cylinder would live somewhere under there.


    IMG_2421.jpg
    The picture shows the almost complete chassis fitted to the footplate. Front and rear frame brackets can be seen along with the brake pull rods, drain cocks etc. I think it’s only the cut outs in the frames for the copper clad mounts for the top wiper pickups to complete.
     
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  6. davey4270

    davey4270 Western Thunderer

    31. Pickup Mounts and a Start on the Cab Detail.

    Copper clad has been soldered to the frames for pickups to be fitted and I’ll need to modify the firebox to fit a larger motor.
    As always, more captions with the pictures.


    IMG_2428.jpg
    With this early kit there are no cut outs for mounting the copper clad. Having built several others of its ilk this was not a problem working out where they went and filing out the slots. The 2 leading axles have one between them just behind the slide bar support bracket and the trailing axle has one just above the rear sand boxes. I cut a couple of slots with my new razor saw, don’t ask what I did with the other one, and filed down until the copper clad would fit slightly below the top of the frames. If they are too high they will stop the footplate sitting flush on the frames. I think the copper clad I used was for 4mm track construction. Of course the copper has to face down and I soon realised that it would be impossible to solder the rear pickups due to the location of the sandboxes! The picture shows another slot between the 2nd & 3rd axles for the rear pickup mount and the copper clad mount gapped ready to fit. You will need to remove 1mm of copper from each side just clear of the outside of the frames to give electrical isolation then solder from the inside and below.


    IMG_2429.jpg
    The copper clad soldered in position and the vacuum pump manifold glued on top of cylinder. I cut the wire brake hanger between the frames to give access to my soldering iron and will probably cut the copper clad before painting. Certainly the rear one will need to be cut to give space for the motor.


    IMG_2430.jpg
    I fitted the coupling rods to check that there was clearance with the slide bar support brackets and was quite happy that everything still spun freely with no tight spots.


    IMG_2431.jpg
    The start made on the cab interior with the floor/bunker front formed, hand brake fitted, bunker door & handle fitted and the reverser rack fitted. The reversing lever will slot in and pivot on a piece of 0.7mm wire threaded through the hole at its base. Question, is the release catch on the lever to the front or the back?
     
  7. davey4270

    davey4270 Western Thunderer

    32. The Chimney.

    I like my chimneys to be hollow so it needs to be drilled out. This is hard work and I’m glad the chimney is white metal and not cast in brass!
    As always, more captions with the pictures:


    IMG_2434.jpg
    The chimney has a recess of about 5mm before the centre becomes solid. I started drilling a 1.5mm hole as central as possible with a pin chuck switching between top and bottom. Fortunately they met almost in the middle and I was able to work up to a 2.5mm hole which is the largest bit that either of my pin chucks will accommodate. I have a tapered reamer which I then used to gently enlarge the hole working equally from top and bottom until I was satisfied with the hole. This was not easy as the soft white metal clogged the reamer after only a few twists and needed to be cleared regularly. The hardest part is holding the chimney without damaging it. Finger tip pressure is all that can be used possibly with a few layers of kitchen roll. My fingers will be quite sore for a few days, there must be another way!


    IMG_2438.jpg
    There is an offset lamp iron in front of the chimney and this led to a conundrum. Do I fit this first then have difficulty cleaning up around the chimney or fit the chimney first and hopefully not damage it soldering the lamp iron on. I went for option 2 and hopefully haven’t made a mistake. The iPhone lens has some distortion at the sides but the chimney is straight.
     
  8. simond

    simond Western Thunderer

    Davey,

    I agree with your desire to hollow out the chimney. I settled for a partial (but at least round) hole at the top of the chimney of my Garratt (build is on t’other channel). I chickened out before I messed things up, but th3 approach doesn’t lead to sore fingers.

    Another Beyer Garratt 0-4-4-0

    hth
    Simon
     
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  9. davey4270

    davey4270 Western Thunderer

    I don’t do anything on RMWeb since they deleted all my pics, could you describe your process here please. Unfortunately the reamer has exceedingly sharp edges and the base of the chimney does some damage to the fingers too. I’m still trying to work out if the end result is worth the discomfort.
     
  10. simond

    simond Western Thunderer

    I don’t suppose they’ll mind if you look :). I hope they don’t delete mine, I have too much to move.

    anyway, the chimney is furnished with a spigot to fit the hole in the boiler, happily, it’s concentric with the top. I mounted that in a Unimat dividing head set vertically in the miller, and used a 3mm 2-flute milling cutter. I fed it into the indeterminate hole provided by the casting process (I assume the mould core had broken) and then rotated the dividing head by hand to mill a hole larger than the cutter. I then used the feed on the miller table to make the cutter more eccentric from the axis, and repeated the process. Very small feeds & depth of cut, slow progress.

    upload_2020-11-26_7-19-6.jpeg
     
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  11. davey4270

    davey4270 Western Thunderer

    I don’t have a lathe so all done (painfully) by hand.