Entry posted by D869
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Fitting the Cabs
To recap from the previous installment... I think that the cab sides need to taper slightly inwards from the doors to the nose, but the kit seems to assume that this doesn't happen.
I took some dividers and marked 0.5mm in from the widest part of the nose ends. I filed down to these marks and then continued the filing down to the buffer beam level, checking with a square that the edge was truly vertical. The photo below shows a modified end compared with the original still on the fret.
I cleaned out the handrail/location holes with a 0.3mm drill and put some fine steel wire into place. I then added three of the four backing pieces. I had other ideas for number 4 but in the end leaving it off seems to have been the right thing to do. I then filed down the three backing pieces to match the reduced with of the nose end and cleaned up any etching cusps on the top. This is also a good time to file the curve on the top of the nose end. Here is a handy photo as a rough guide to the correct radius. http://www.flickr.co...N02/2366710181/
Next I bent the cab sides inwards slightly, checking against a ruler laid against the main sides to ensure that I bent both by the same amount. Ideally the cab sides should just grip the reduced width nose end. Having done this it was time to solder the nose end into place - after very carefully aligning it with the sides and checking to ensure that no twist is creeping in. Once the nose end was attached and thoroughly checked for position, I soldered on a couple of pieces of plain rail (or 20 by 40 thou strip if you prefer) to reinforce the inside of the corners given that I was about to attack the outside of the joint with a file.
The next step was to file the radius on the vertical joint between the nose and cab sides. I haven't quite decided whether this radius is the same as that along the top of the nose or whether it was larger. Mine has roughly the same radius, perhaps a little more.
Throughout the previous steps I had been wondering what effect my changes would have on the fit of the cab windscreen surrounds. I reckon that these were intended to fit between the sides but I tried matching mine up to the ends of the sides after first forming them into a shallow (about 2mm) vee shape. Fitting them this way partly compensates for the reduction in width but I was expecting to get some overlap and possibly need to cut a piece out of the lower edge of the frames. In the end the alignment turned out a lot better than I had dared to hope. Given the choice of having a 10 thou edge showing at the front of the cab or ahead of the side windows I would go for the latter anyway (I guess I could have bevelled them if I was really being fussy).
At this stage I also formed the cab roof to shape and tried it in place. All was not well because the windscreen surrounds were sitting atop the side sheets of the nose and pushing the roof up resulting in a 0.5mm gap between the roof and the top of the side windows. My solution was to take the windscreen surrounds and carefully file away some of the bottom corner. Measuring using the calipers from inside the windscreen to outside the corner I got 1.5mm before attacking them. I think I reduced this to about half of its previous width. I then tried everything in place again and was amazed to see that the cab roof fitted really well and that the windscreens appeared to 'sit' nice and low on top of the nose - just like the prototype.
Next I soldered the windscreen surrounds into position followed by the roof. I also found that the centre pillar of the windscreens was just touching the number 3 backing piece of the nose - so I was glad that I left out number 4 and soldered the two things together where they touched. Of course there is still a gap between most of the windscreen surround and the number 3 backing piece which will need to be filled (another day). I then soldered the cab roof into place. After this there was a step of about 0.5mm down from the main roof to the cab roof which is not prototypical. I will tidy this up with Milliput once the soldering is all done.
The big task that I now had was blending the cab roof into the windscreen surrounds. To start with I had a pretty big gap between the two (see photo below) and the roof was overhanging the cab front slightly. I started by filing the front edge of the roof until the overhang was gone. Then I soldered a suitable size of fuse wire on the inside of the joint to fill the worst of the gap. A few extra touches with the soldering iron plus plenty of solder and green label flux eliminated the remaining gaps.
It was then just a matter of filing down the roof and various fillers until I achieved what appeared to be the correct transition between the roof and front. It's difficult to describe this in words, but it might help to say that the transition ends at the top of the windscreen surround etching. Basically you need to look at lots of photos and get a feel for the three dimensional curves yourself.
The final filing job is probably the trickiest - the top of the nose ends in quite a sharp corner where it joins the sides. This is not prototypical and needs to be blended in, requiring quite a lot of metal to be removed. I used a flat file with a safe edge (i.e. an edge with no teeth) against the windscreen surround to do most of this work, keeping the file parallel to the angle of the windscreen. Blending all of the curves around the edges of the nose together is the final step in the shaping process. The photo below shows this job in progress - the corner on the right has been done but the one on the left has not yet been touched.
To finish off, I went back over some of the etched lines with a sharp knife and scraper to remove any surplus solder that had crept in to spoil Mr Doherty's hard work.
In the next installment I will start on the roof... where again I've departed from the kit in a pretty major way.
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