99 3462 Build diary

[mbrown]

Boiler Barrel Cleading

Today 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

[jma1009]

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

[mbrown]

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

[mbrown]

Cleading, handrails, dome and more


A 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

[mbrown]

Finishing the dome


In Deutsche Reichsbahn days, 99 3462 had a small wheel valve mounted on the front of the dome. I have no idea what it was for....


Dome valve close up by malcolm brown, on Flickr


Mine is a dummy - to give an idea of size, the wheel is made from 1/4" hex with the flats radiused and fitted with a 12 BA nut. It was a spare made when I constructed the hydrostatic lubricator for the Burma Mines loco which has three of them to control the steam and oil flows.


20240512_181737 by malcolm brown, on Flickr


20240512_181725 by malcolm brown, on Flickr


In the lower photo you can see one of the two 6 BA countersunk Allen screws which hold the dome cover down - these screw into spacers which in turn are screwed into blind holes in the top of the inner dome.

I have also started work on the expansion links, so more about them next time, I hope.

Best wishes

Malcolm

[chris vine]

Hi Malcolm,

I wonder if the little valve was for a flexible hose to a steam lance for cleaning the boiler tubes?

Just a thought...

Chris.

[mbrown]

It's a possibility Chris. Most of the MPSB locos had similar valves but the fact that they were always on the dome makes me wonder if there was a different purpose as a steam lance valve could be in other, easier to access, locations.

The standard DR fittings included some that are odd to UK eyes - like take-off points on the injector delivery pipes which, I gather, were so that a hose could be fitted for fire-fighting. The hose would gave got pretty hot!

Malcolm

[chris vine]

I think that on UK engines with a "slacker?" hose, for washing down the footplate and coal, the hose was also taken from the injector delivery.
Hot pressure wash with almost no extra equipment!

Chris.

[ettingtonliam]

For filling the boiler from cold with a hose pipe?

[mbrown]

That is certainly a possibility - although it doesn't explain why it is up there on the dome as you can fill the boiler from virtually anywhere. The high position suggests that it is to feed fairly dry steam to ... something or other.

On reflection, one possibility may be that it was to supply steam to a water lifter or a pump to raise water to a water tank. The MPSB ran across low-lying marshland and films show a number of derelict windmills in the area, presumably for drainage. That suggests that there wouldn't be much head of water to supply the water columns (of which there were several). Maybe there was once a steam pump or something similar, maybe in a shed close to the track, and locos supplied steam through a flexible hose whenever the tank needed pumping full. It would save the costs of a separate boiler and staff to keep the boiler in steam.

Unfortunately, I don't read German, so I don't know if the history of the line (by Wolf-Dietger Machel) mentions anything like this. I certainly haven't seen any photos to bear it out. But in pre-preservation days, Dolgoch on the Talyllyn was fitted with a stop valve on the boiler barrel, precisely to supply steam to a small stationary engine that lifted water into the original Pendre water tank. So there is a precedent.

Maybe I will find out one day!

Malcolm

[mbrown]

Expansion Links


Having drawn the valve gear arrangement and most of the parts in CAD, I got the expansion links water-jet cut from MEL - and very nicely done they were. They needed a certain amount of draw-filing to get them looking nice, then the hole in the tail bushing, but it was a lot less work than cutting them from solid. At the same time, I also got two backing plates cut from 1.5 mm sheet thus guaranteeing that the outline and, most of all, the fixing holes, lined up perfectly.

The radius rod embraces the expansion link which is pivoted, in typical Orenstein and Koppel fashion, on a long bearing on the inside. The backing plate thus needed the pivot bar and two spacers silver soldering on. Here are the expansion links with one completed backplate and the other awaiting assembly. The hole in the backplate has a small notch filed in to ensure good solder penetration.


20240519_140117 by malcolm brown, on Flickr


The holes to attach the link to the backplate are reamed through at 1/16" and fitted with 10 BA bolts, secured with 12 BA nuts tapped out to 10 BA. In full size, these surprisingly small nuts have split pins through the ends, but I will use a dab of Loctite nut lock on final assembly. They do have to come apart to enable the expansion link and radius rod to be fitted together via the die block.


20240519_173215 by malcolm brown, on Flickr


And here is one of them on the loco. The bearing block mounted on the frame was left deliberately long by 1/32" or so, and will be trimmed back so that the securing nut can be tightened without affecting the freedom of movement.


20240519_173240 by malcolm brown, on Flickr


Unlike most UK locos, the expansion links are very exposed - it was the sight of them swinging to and fro as the loco moved that first endeared me to 99 3462!

Best wishes

Malcolm

[mbrown]

Snifting Valve and Blower elbow

Two more small parts completed today, moving toward completion of the smokebox end.

The big 99 3462 didn't need a snifting valve as it had Trofimoff piston valves which slid along the valve spindle to create a by-pass. I wasn't going to attempt that in this scale, so my snifting valve is straight LBSC or Martin Evans, fitted with a 3/16" dia ball. It is a push fit in a hole through the bottom of the smokebox, emerging just ahead of the saddle. On the prototype, which was fitted with water jets to clear the smokebox of char, there is a drain pipe here which emerged, in DR days, through an apron plate across the top of the buffer beam. My snifting valve will drain down between the frames and the outlet to the drain will be a dummy, otherwise it would be very tricky to assemble.

The blower valve itself is on the cluster of stop valves along side the dome, and this feeds to an elbow on the smokebox side. Mine is secured by a 1/4" x 40 nut on the inside, the long threaded portion allowing room for the usual union to take steam to the blower ring.


20240525_180520 by malcolm brown, on Flickr


I had to remove the turbo generator and its bracket to fit the elbow - in full size, the elbow is completely concealed inside the generator bracket and almost invisible. I have moved the elbow back so that the union is accessible without removing the generator bracket, the associated pipework and so on if it needs maintenance. With everything here painted black, it shouldn't be obtrusive.


20240525_181135 by malcolm brown, on Flickr


And here they both are, looking from within the smokebox. The steam pipes are yet to be coupled up and the blastpipe has been removed for now - the boiler and smokebox will need to come off the frames a few more times before everything is ready to put together permanently.


20240525_181225 by malcolm brown, on Flickr


Nothing very exciting, but a little more progress...

Best wishes

Malcolm

[mbrown]

Damper linkage


I have been thinking carefully about how to hold the radius rods for machining - I think I have found a sequence and may get to deal with them in the next few weeks. But in the meantime, I have got on with various odd jobs including, this weekend, the linkages for the dampers.

There are a number of puzzles here. First, in order to remove the grate from the rear, the damper linkages have to be right up close to the left hand frame plate. Second, although the rear damper is easy to access, the front one is hidden ahead of and between the rear wheels, with very restricted space to get to it, and almost impossible to see when the boiler is on and the ashpan is in place.

After careful measurement of the chassis and the ashpan separately, I concluded that I has just enough room to run a rod to a crank on the front damper provided the rod hugged the side of the ashpan closely. There was just room for a small bell crank at the front, but with only a fraction of an inch before it fouled the rear of the wheel.


At the rear end, the pivot for the rear damper was extended well to the left, so I put the cranks for the front damper on a tube which runs on the pivot, with the lever for the rear damper added separately. Here it is with the mechanism for the front damper in place.



20240528_151036 by malcolm brown, on Flickr


The operating rod has a short pin through the front bell crank - it can't come out because the ashpan side prevents movement in that direction. The other arm of the crank at the rear will have a horizontal pull/push rod to operate the damper from the footplate. This is as per the real loco, at least in preservation. I have no information about the ashpan and dampers in DR days except that the ashpan wasn't the same as the present one as one can see more light under it in photos!

And here it is with the operating arm for the rear damper fitted. This connects to an up/down "walking stick" handle in the cab - again, as in full size except that the lever will be further to the left. The two operating rods, which I will have to make much later when the cab is in place, can run close against each other as they move in different planes.



20240528_151442 by malcolm brown, on Flickr


This rear view may give a better idea of the arrangement. The ashpan is lying on its right hand side. The grate would be on the right and the drop door is on the left.


20240528_151540 by malcolm brown, on Flickr


While I had the boiler off, I dealt with a couple of other odd jobs. The bearings for the expansion links had to be removed and faced back so that the links pivoted freely but without end slop. While they were dismantled, I removed the top plate over the frames as I had discovered that, somehow, I had 1/8" too little room between the rear of the top plate, which coincides with the front of the cab, and the rear buffer beam. This would have left the cab overhanging the buffer beam by 1/8". Considering that all the measurements were taken from the full size loco, working in a cramped and dark shed, I don't think 1/8" out is too bad.... and at least it was 1/8" too much, not too little, so I didn't need a "putting on tool". Trimming the top plate involved removing various angles and refitting them, and sealing up a few now-redundant rivet holes, but it's all done now and, eventually when the cab is built, it should fit properly.

Best wishes

Malcolm

[mbrown]

Running Board Brackets

Today I completed a job that I should have dealt with ages ago - adding four brackets to the frames to support the cab and rear running boards.

On the full size engine, these are not easy to see and I didn't remember to measure them when I was on the WEM. But the basic dimensions are obvious from their positions. I think the full size ones were probably constructed from plate and angles, but I had run out of small steel angles so flanged mine up from plate in the vice.

To get the edges all the same, they were clamped down in the mill and a cutter run around them.


20240601_143617 by malcolm brown, on Flickr


Lining them up took a little care, but they all went neatly into place - just as on the prototype, the bottom of one corner needed relieving to clear a rivet in the frame.


20240601_160246 by malcolm brown, on Flickr


Another small step on the way...

Best wishes

Malcolm

[mbrown]

Rear Running Boards


It took me some time to work out the arrangement of angles supporting the running boards under the cab of the prototype - they had clearly been changed significantly in its first preserved guise and clear photos of the area under the cab in DR days were scarce - the one below was the best I had.


Foto Randolf_Jaentsch 002 by malcolm brown, on Flickr


Fortunately, I later acquired a book with one beautiful shot from very low down at the rear 3/4 position which confirmed that the main angle is inset compared to the edging angles on the forward sections of the running boards, and the area which extended sideways beyond the cab had a smaller angle pointing upward, presumably to prevent the enginemen's feet slipping off.

So here is the model version - I only had time to complete one side today. The main angle is more of my home-made 3/16" x 3/16" x 1mm angle, cut down from a wider section from B&Q and the smaller angle is commercial 3.5mm x 3.5mm x 0.5mm brass angle. As the latter is rather flimsy, especially where one web had to be cut away to allow the bends, the angle is fitted with a few 3/64" copper rivets and then sweated onto the running board for rigidity.


20240602_181832 by malcolm brown, on Flickr


(I should have put some sort of background screen in place to hide the piles of junk in the corner of the workshop...!)

I will aim to complete the other side next weekend.


Best wishes

Malcolm

[mbrown]

Smokebox "Bib"


I have had no workshop time for over a month so it was good to be back today. First job was to complete the left hand rear footplate - simply a mirror image of the one shown in my last post. Then I moved around to the front of the loco...

In DR days, the prototype had water jets to clear char from the smokebox, apparently a necessity due to the poor quality coal available in the DDR. A drain pipe led from the bottom of the smokebox to emerge over the front buffer beam and sealed with a hex cap. As supplied by Orenstein and Koppel, this pipe was fully visible as a right angle bend. But at some time, probably post-WW2, she was given a "bib" - a steel plate angled below the smokebox door, which must have made cleaning out the smokebox a much simpler chore. The front of the drain pipe now emerged through that plate as below.


99 3462 by malcolm brown, on Flickr


First job was to put in place the original plate which covered the gap between the frames and the buffer beam, curving up to the front of the smokebox saddle. My snifting valve emerges exactly where the drain pipe should go, but instead of curving forward, it drops between the frames so that any drips fall clear. This is more or less how the pipe was arranged after preservation.


20240714_175215 by malcolm brown, on Flickr


The plate isn't a brilliant fit at the right hand end, as seen here. A tweak with pliers improved the fit later.

Then I made up a dummy drain pipe and cap, turned from 1/4" BMS hex, silver soldered it to a backing plate and rivetted the lot onto the sloping plate.

20240714_175808 by malcolm brown, on Flickr

I am not sure whether to add the tiny chain which retains the cap. It would probably be a nuisance when cleaning the smokebox, but I may change my mind later.

The plates over the sides of the buffer beam were always chequer plate in full size. I have made them from the aluminium chequer plate supplied for 7.25"g models which looks about right here. In fact, the middle plate under the "bib" should be chequer plate too, but you don't seem to be able to buy it in large enough pieces, and it is more or less invisible anyway. The side plates will need angles, a small bracket underneath, lamp holders and steam-heat cocks adding - quite a lot of work for such small parts. But that must wait a while.


20240714_180424 by malcolm brown, on Flickr


Best wishes

Malcolm

[mbrown]

Which thread?

I am wondering whether to shift this whole thread to the "Build Thread" as others have done, or to stay where I am along with Roger and a few others. It isn't easy to know which thread is likely to get the most views.

So, as an exercise in direct democracy (!), if you think the thread should move to the Build Thread, "Like" this post, and if enough forum members do so, I'll make the shift.

Best wishes

Malcolm

[chris vine]

Hi Malcolm,

Personally, I don't like the move to build threads.
I used to just look at the General area and find almost everything was happening there.
Then some people wanted topics which were less build or ME oriented moved to Off Chat and then we had the move of build threads to a new area.
Now I have to go dotting about to find that nothing much has changed and no new posts.

So, for my vote, I would just put (almost) everything in the General section. At least you can see what is going on in one place.

Just my opinion and how I find the forum.

All best
Chris.

[oldnorton]

This might help modeleng.proboards.com/threads/recent

Save that in your browser bookmarks and you only have one page to ever look at.

Norm

[RGR 60130]

Jul 14, 2024 19:49:39 GMT chris vine said:

Hi Malcolm,

Personally, I don't like the move to build threads.
I used to just look at the General area and find almost everything was happening there.
Then some people wanted topics which were less build or ME oriented moved to Off Chat and then we had the move of build threads to a new area.
Now I have to go dotting about to find that nothing much has changed and no new posts.

So, for my vote, I would just put (almost) everything in the General section. At least you can see what is going on in one place.

Just my opinion and how I find the forum.

All best
Chris.

If you go to the bottom of the Home Page you’ll find a section called ‘Forum Information and Statistics’. In the sub-section called ‘Threads and Posts’ there’s a link called ‘Recent Posts’. Clicking on that link will bring up every recent post in chronological order. I tend to stay logged in and just refresh the page every day. That way I don’t have to do any dotting about.

Reg