mbrown
Elder Statesman
Posts: 1,720
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Post by mbrown on Apr 14, 2024 18:11:15 GMT
Boiler Barrel CleadingToday saw the cleading over the boiler barrel more or less completed. Locating the holes for the bushes accurately was quite challenging, despite using a cardboard template. The brass is springier than card and so, to be sure, I put a small hole at the centre of where I thought the bush should be, tried the cleading sheet in place and drew the hole over with a round file until it was concentric with the middle of the bush. Then I used a cone-cut to open the hole out and keep it perfectly round. Incidentally, I decided to use 22 swg brass for the barrel and firebox, with 16 g brass for the backhead and throatplate. The fairly thick brass is harder to fit to the boiler but holds its shape and the risk of creases and dings is less than with the usual very thin sheet. Getting the boiler bands exactly the right length was also "interesting" - long enough to get a screw to engage with the lugs at the bottom, but short enough to pull the plate around the barrel tightly. That took two or three goes, and the rear one could be a bit tighter still... 20240414_183209 by malcolm brown, on Flickr The barrel cleading has to come off again - first, to fit the supports for the handrail knobs and also to insert 1/32" rivets in the rows of hole that can just be made out ahead of the clack bush. On the full size loco, these are fairly prominent screws either side of a join in the cleading - I have represented the join with a deep scriber line and drilled the holes prior to rolling the sheet. The rivets will be lightly closed on the inside and the tails sweated over. That's it for another weekend. Best wishes Malcolm
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Apr 14, 2024 21:52:46 GMT
Hi Malcolm,
That is looking very good!
I hope that you might experiment with an alternative to the police whistle - say 4psi lung pressure compared to your working boiler pressure (despite what LBSC wrote about police whistles).
Cheers, Julian
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mbrown
Elder Statesman
Posts: 1,720
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Post by mbrown on Apr 15, 2024 6:19:18 GMT
Thanks Julian.
I did the experiment 40 years ago! My Bagnall 0-4-2T has an identical police whistle and it gives a very good two-note chime on 80 psi delivered through a 1/8" tube. Surprisingly, perhaps, the sound is much weaker below about 60 psi. I guess the answer is to keep your pressure up....
So LBSC was right!
Best wishes
Malcolm
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mbrown
Elder Statesman
Posts: 1,720
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Post by mbrown on Apr 21, 2024 17:38:33 GMT
Cleading, handrails, dome and moreA busy weekend in the workshop sees the boiler cleading finally fitted. All three boiler bands had to be shortened in order to pull the cleading sheet up tight. I also put 1/32" rivets in the pre-drilled holes to simulate a cleading joint along the centre line forward of the middle boiler band. The handrails on 99 3462 are fitted to a small pad secured to the cleading by two hex head bolts, as seen below: Handrail knob close up by malcolm brown, on Flickr I started making these with a strip of 7/32" x 18g brass, drilled with holes for the handrail knobs and two smaller holes either side. This was then bent to the radius of the boiler clothing before separating each pad (3 holes per pad) and trimming the ends with a file. 20240420_155210 by malcolm brown, on Flickr With the cleading off the boiler barrel, the position of each handrail knob was then marked out and drilled. A nut and bolt held the pad in place while the two outer holes were drilled and tapped 12 BA and each pad was then secured with two 12 BA brass hex head screws and the middle nut and bolt removed. The pads were sweated into place and the middle hole tapped 6 BA for the handrail knob. The knobs were modified from commercial ones - the length can be altered by turning off the collar and either substituting a longer one or shortening the stem and adding a new collar. Two extra knobs and pads were needed for the shaft which operates the whistle. This was mounted, and its operating arm with a Tufnol handle duly fitted at the cab end. German practice seems to be that most controls that get hot and need regular use are fitted with wooden handles. With the regulator handle and firedoor fitted, it begins to look the part. 20240421_171318 by malcolm brown, on Flickr The dome needed to be cut away to accommodate the steam take-offs on either side. The opening in the top of the dome cover was enlarged into a rectangle, as on the prototype, to fit around the safety valves which have square flanges. At a later point, I will arrange for the dome cover to be screwed down securelt to the inner dome. Finally, the sandbox was fitted, using a stud screwed into the boiler bush, and a strongback inside the box to hold it down nicely. With the whistle ad its valve in place, and the bell lodged on its mounting (I need to remake the working parts of the bell) the loco begins to acquire its "sky line"! 20240421_171510 by malcolm brown, on Flickr Not sure why the photos have come out over-exposed.... Anyway, that is it for a few weeks. Best wishes Malcolm
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