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Brackets and Brakes

Posted by Kenton , 29 November 2009 · 923 views

brakes suspension wheels jacking brackets
Finding a small box I have put the gussets aside for now.

The instructions now continue adding more detail, the front footplate hand-grabs, more lamp brackets, more resin mouldings (the lights) and the buffers. As already indicated I do not like adding this sort of detail until the heavy handling is complete and I really don't like adding buffers and their springs until after the model has been painted - or just for show. So all these will be left off for now and hopefully remembered later.

Moving on to the jacking brackets [49] these also have rivets that require punching out and are made up from a folded panel and a pair of tiny side wings. Once again, a part that is attracted to the carpet magnet and for which there are no spares on the fret. I also found that they were extremely sharp and managed to draw blood. After folding the bracket, the wings were soldered in place in the half-etched grooves and then the completed brackets were soldered to the buffer beams in line with the rivets. What is quite clear from the drawing and from photos is the position of these brackets, what remains puzzling is why the rivets on the buffer beam were required as they are obscured by the bracket.

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Now is as good a time as any to fit the wheel balance weights [58] to the wheels. They are positioned opposite the crankpin holes and obviously need to be glued in place. I used superglue. I also dipped the wheels in Carr's blackening to remove that shine after a thorough clean with the glass fibre pen and a wash in isopropyl alcohol.

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Alas they didn't come out as well as they usually do, discussed HERE

The brake pivot flanges [46] each have rivets that required punching before removal from the fret. Then two lengths of 0.5mm wire were passed through the brake pivot holes on the frame leaving plenty of room on either side to suspend the brakes. The flanges were then added to the outside of the frames.

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The brakes were assembled by laminating together the inner layer [47a], the fragile middle layer [47b] and the outer layer [47c]. Remembering that the brakes are sided and lead the wheels. The wheels were refitted to the frames to assist in alignment. is difficult to avoid filling the holes with solder during the lamination process and I had to re drill them, they were correctly a little undersized anyway. The brakes are fitted with the shorter arm uppermost to the brake pivots. This is well illustrated in this photograph taken by John Howell (26power). Remember that the brakes must be set far enough back from the wheel rim in order that the wheel may be removed and that there is no chance of them touching and shorting any part of the wheel as it moves. Once soldered in place the wire was cut back and filed flat.

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Now, this is not a criticism of this kit in particular but a broad comment on brass and metal kits in general. If a model was produced without brakes it would look ridiculously incomplete, however, they are never going to be anything like the prototype they are modelling. Just take a look at any locomotive braking system and you will see just how close the brake shoes are to the wheels even when the brakes are off. In terms of scales they are in effect touching. No one can reproduce this appearance and especially in metal. As in the case of metal if they come into contact with the wheels then a short will occur. So they always have to be positioned away from the wheel rims. This is exaggerated even more when the wheels are compensated or sprung as there will be movement of the wheels other than pure rotation. Add to that the difficulty of producing realistic brake systems from laminations and I have to ask the question: why not produce them from cast resin?

The brake cross beams [48a] were removed from the fret (good luck - the positioning of the tags on these must be a mistake, why not one in the middle?). These beams were soldered across the lower holes of the brakes, across the frames, the ends trimmed and filed back in the same way as the upper pivots. Maintaining clearance on the fixed axle was easy and the shoes can be locked in position quite close to the wheels, but on the compensated axle there is too much flapping about and they need to be set quite a bit back.

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Locate the cross shaft parts and remove from the fret. The cross shaft flanges [48] were soldered to the outside of the frames in their half-etched recesses. The main cross shaft was made from a length of 0.8mm wire (supplied) this was inserted through the holes in the rear of the frames and through the crank [62] before soldering to the inside of the frames. The brake cylinder arms [63] were then soldered on each end before trimming the wire with a piercing saw and filing flat.

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Once again, thanks to John Howell (26power) for his photographs of the preserved D2767 which clearly show the brake cylinder on only the left hand side and a spring on the right hand side (after messing a bit with the image's colour balance). The brake cylinder is another resin part and will be added later, prior to painting.
You may have observed that I have replaced the steel pivot pins for the compensation arms with new shorter brass wire in an attempt to tighten the suspension - with marginal success. What was a very free wheeling model is now far too tight. The thought has crossed my mind a number of times to go back to both fixed axles.

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A brake pull rod is represented by soldering a length of 0.5mm wire from the crank to the centre of each brake cross beam. Once again I am unsure of the need for this and it may well be removed. The same old argument of trying to represent something on the prototype that cannot be realistically be done on a model and that cannot be seen anyway.

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Finally a length of 1.2mm wire (supplied) was cut to approximately 22mm with the end faces filed flat and soldered across the centre of the frames to represent the low level fuel filler.

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Sitting here with the brake gear from three different locos within reach, I can entirely sympathise with your comments about realism, separation, shorting etc. What I've tried to do, following the example of a couple of High Level chassis kits, is to make the whole lot removable. By not soldering the hangers to their pivots, they can be sprung on of off as needed should you want to remove the wheels. The connection between the pull rod(s) and the cross-shaft levers is also not soldered so that the whole brake gear can be hinged out of the way for access to the wheels.

Another possibility is that Alan Gibson lists injection moulded plastic brake gear that can be placed close to the wheels without shorting. I've not tried these and there are not many types; the only diesel type is for an 03 (knowing almost nothing about diesels, I've no idea how closely these would match your little beastie).

Nick
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Michael Edge
Nov 29 2009 20:29
If you press out the rivets on the buffer beam they locate the jacking brackets - very simple, works very well. I've used the same system to locate horn guides on Steelman locos and BR Anhydrite hopper underframes.
I've used plastic brake gear in the past, it's difficult to fit accurately and very fragile. You can get metal brake blocks very close to the treads if your wheels are concentric, they may foul the compensated axle though. the pull rods are useful in keeping the brakes at the same distance from the treads, if you don't put them on it's easy to move the brakes while cleaning the wheels. Don't forget that the compensating arms were supposed to be right against the inside of the frame plates. GA drawing with kit quite clearly shows the brake cylinder on the LH side, I do seem to have forgotten about the arm and spring on the other side though.
Michael Edge

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