99 3462 Build diary

[mbrown]

Boiler support brackets


I managed to slip away for an hour or two this afternoon, so a little more progress has been made....

On 99 3462, the boiler is supported at the back by bronze slippers fixed to the top frame angle on which the foundation ring sits.


DSC00489 by malcolm brown, on Flickr


This was easy to reproduce, although it also gave me an opportunity to make the two slippers slightly different heights as my boiler is not quite square in every dimension and this enabled me to set the dome vertical and the rear foundation ring level. It's a matter of an extra 1/16" on the right hand side.


20231223_162740 by malcolm brown, on Flickr


The slippers keep the boiler located side to side. To prevent the rear end lifting, I shall have to invent some brackets as I intend to allow the grate to be withdrawn to the rear, and the expansion brackets on the prototype would be in the way of this. A job for another day...


Best wishes

Malcolm

[mbrown]

Grate supports


As the rear foundation ring is higher than the cab floor, it seemed worth scheming out a plan to enable me to withdraw the grate from the rear, dropping any fire into the ashpan. This is why I left the "skirts" of the inner firebox rather long when building the boiler.

Below, I have screwed two lengths of 1/4" square copper to the firebox skirts, with the tops level with the top of the frames. At the back, is a little clip in stainless steel which will support the rear of the grate. The gap at the front of the copper bars is for two reasons - first, it saves me shaping the bars around the tubeplate flanges, but second, it will allow ash to drop clear of the bars at the front corners which are quite restricted for space.


20231226_174633 by malcolm brown, on Flickr


With the boiler mounted in the frames and a piece of sheet representing the cab floor which hasn't yet been made, it shows how the grate can slide in onto the side bars. The grate is a Blackgates stainless grate with tapered bars - the corners are bent in to clear the tubeplate and door plate flanges.



20231226_175125 by malcolm brown, on Flickr


Once the grate has been pushed up to the tubeplate, the rear end is lifted and the catch pushed around to support the back end of the grate.


20231226_175138 by malcolm brown, on Flickr


The catch idea was pinched from LBSC's Maisie design - he uses a loop of bent wire whereas I made a small plate from stainless, but the principle is identical. The plate pivots on a shouldered screw tapped into the foundation ring.

Clearance between the front of the grate and the rear wheels is pretty tight, but by fixing the ashpan to the under side of the copper bars, I gain a little more space compared to fixing the ashpan to the foundation ring. Ash may end up collecting in the corners, but it should be easy enough to get a poker into the corners under the grate if necessary. The full size loco had water sprays for clearing the front of the ashpan, but I am not going to follow suit!


Best wishes

Malcolm

[mbrown]

Boiler Expansion Brackets

Although none of the Orenstein and Koppel drawings survived the War, sometime after the creation of the Deutsche Reichsbahn, a development of 99 3462 was drawn up but never built - and the GA is in the Dresden Steam Museum. Sven Schlenkrich got me a copy and, although it is of limited use in modelling 99 3462 as many basic dimensions were altered, it does show the arrangement of the boiler expansion brackets which also hold the rear of the boiler in place. I have copied this arrangement, except for moving the brackets outwards so as to avoid blocking the grate as it slides (unprototypically) in and out.

Small brass blocks, with a 1/4" x 1/8" slot, are screwed to the firebox skirts and a piece of angle, with a matching lug to slip into the slot, is mounted on an angle screwed to the top frame angle.


20231227_184705 by malcolm brown, on Flickr


The two 6 BA Hex head screws can be removed easily from the rear, allowing the angles with the lugs to be removed and freeing the boiler for lifting. When in place, they hold everything firm but allow about 1/8" for rearward expansion.


20231227_184557 by malcolm brown, on Flickr


Hoping to make more progress over the New Year holiday.

Best wishes

Malcolm

[mbrown]

"Brick" Arch


Because the firebox is quite shallow, and having had trouble on another loco (Lyn) with the bottom row of tubes blocking and putting her off the boil, I wanted to try a brick arch this time. The side stays include two hollow ones each side, which allow stainless pegs to be inserted (and removed if necessary).


20231228_161743 by malcolm brown, on Flickr


The arch is made of 18g stainless - and it took several attempts to shape one that was capable of being inserted and lodged in place. Even so, I am not wholly happy with it - if the boiler is inverted, it drops out of place and getting it back on the pegs without lifting the boiler is extremely difficult. It strikes me that it is asking for trouble to have a consumable and loose item in a place where it can't easily be accessed - but I will experiment a bit before deciding finally. I could possibly devise a tool to hold it at the right angle through the fire door to wangle it onto its pegs ....


20231229_121034 by malcolm brown, on Flickr


I am also wondering if the stainless sheet will survive long in the firebox. I wondered about coating it with a thin layer of fire cement ("Pyruma") to make it more authentically a brick arch. Getting the cement to stick might be challenging, but some large diameter holes in the plate might allow the two sides to bind to each other.

I wonder if any forum members have experience of brick arches in various materials - and how to get them in and out of place?

Best wishes

Malcolm

[steamer5]

Hi Malcolm,
Could you put some loops/ washers were the top pins are, with plenty of wriggle room, & fit those 2 pins after fitting the arch in? Or would it then be to difficult to the nuts on the pins?

Looking good by the way!

Cheers Kerrin

[mbrown]

Hi Kerrin,

Unfortunately, the outside of the firebox is not only lagged and cleaded but hidden inside the cab too... otherwise, that would have been a good solution!

On thought that came to me tonight was to put little copper wedges between the sides of the arch and the firebox sides - they would hold the arch but could be knocked out if one needed to dismantle it. But the sides of the arch are invisible from the fire hole and from below because of the angle of the arch - so that might not prove possible.

I'll go on thinking....

How's your K1 Garrett coming on, by the way?

Malcolm

[steamer5]

Hi Malcolm,
Figured that it might be a bit of a push!

On the K1 front it’s moving along…… slowly! I must get my act together & start a thread on my trials & extremely slow progress!
Summer at home & summer projects, including painting the exterior of the house have meant workshop time has been limited! Currently we are in Canada as our youngest son has just got married, so I’ve given him a poke to get the drawings finished for some of the steam circuit fittings finished so I can get Mike to cast them for me, just about finished the drawings for the tanks to get to the water cutter. Then it’s going to be the pivots for the boiler cradle, just got to sort out how I think I can make them or maybe be take a bit of licence & simplify what in full size is a casting to an assembly

Cheers Kerrin

[mbrown]

Bits and Pieces...


I may have solved the problem of retaining the "brick" arch. I tweaked the sides which lodge onto the pins so that the arch was a snap fit requiring a gentle push to get the edges to engage with the pins. The arch is free to breathe but doesn't drop out if the boiler is inverted. I will just have to see if it functions OK in service. I did try the idea of copper wedges, but the angle of the arch is such that it is impossible to wangle the wedges in at an angle that helps retain the arch.

Otherwise, today has been a day of odd jobs as I move toward the point where the boiler is properly mounted. First, the main steam pipes in the smokebox were coupled to the cylinder connections.


20231231_141158 by malcolm brown, on Flickr


The stainless elements had copper extensions silver soldered on and then bent to shape. On the Burma Mines loco, I bent the stainless elements while at red heat. They bent easily enough, but they had to be just so - there was no "give" at all. So I decided copper was the better bet this time.

On the prototype, the expansion link rocker boxes have oil cups with swivelling lids, retained in place by a small spring on a set screw.


DSC00514 by malcolm brown, on Flickr


I reproduced these using a 12BA screw (I may replace the hex screw with a round head reduced in size) and a spring from a Schrader car tyre valve. The picture is a bit out of focus, but it is very small and hard to capture!


20231231_161709 by malcolm brown, on Flickr


In full size, the reverser is bolted to a bracket rivetted to the side of the firebox. This is not a good idea in miniature for a variety of reasons, so my reverser is mounted on a plate bolted to the angle at the top of the frame. The firebox cleading will have to be cut away to clear it, but the overall effect should be realistic.


20231231_181040 by malcolm brown, on Flickr


That may be all I can do before the holiday period ends, but it has been quite a productive time. Once I have designed the ashpan, which I am aiming to make removable without lifting the boiler, I will be in a position to lag and clothe the boiler and/or make progress on the valve gear.


Anyway, Happy New Year to all on the forum.

Malcolm

[mbrown]

Playing about!

I hope I am not the only one who can't resist playing with the bits and pieces to try to picture the finished product!

With no time for serious workshop activity today, I couldn't resist trying the cab sides in place to envisage the size and shape of the loco. I excuse my indulgence by telling myself that it is important to establish clearances etc before laying out the controls in the cab. But I am some way off that stage as yet.

But at least it gives a sense of achievement.

20240102_124153 by malcolm brown, on Flickr


20240102_124231 by malcolm brown, on Flickr


20240102_124027 by malcolm brown, on Flickr


Still a lot of work to do....

Best wishes

Malcolm

[simplyloco]

Jan 2, 2024 13:31:22 GMT mbrown said:

Playing about!

I hope I am not the only one who can't resist playing with the bits and pieces to try to picture the finished product!

With no time for serious workshop activity today, I couldn't resist trying the cab sides in place to envisage the size and shape of the loco. I excuse my indulgence by telling myself that it is important to establish clearances etc before laying out the controls in the cab. But I am some way off that stage as yet.

But at least it gives a sense of achievement.

SNIP
Still a lot of work to do....

Best wishes

Malcolm

You are not alone Malcolm, I do it all the time, mostly for continued motivation!
John

[Cro]

Jan 2, 2024 13:31:22 GMT mbrown said:

Playing about!

I hope I am not the only one who can't resist playing with the bits and pieces to try to picture the finished product!

With no time for serious workshop activity today, I couldn't resist trying the cab sides in place to envisage the size and shape of the loco. I excuse my indulgence by telling myself that it is important to establish clearances etc before laying out the controls in the cab. But I am some way off that stage as yet.

But at least it gives a sense of achievement.

20240102_124153 by malcolm brown, on Flickr


20240102_124231 by malcolm brown, on Flickr


20240102_124027 by malcolm brown, on Flickr


Still a lot of work to do....

Best wishes

Malcolm

I think we are all the same, I finished the valves and I cut pipe just to take this photo, with the cab placed back on. 


Untitled by Adam Cro, on Flickr

Loco is looking great, love watching the progress.
Adam 

[mbrown]

Ashpan


After a bit of scheming, I have made a start on the ashpan, designing it so that, if necessary, it can be removed without lifting the boiler - not easy as the rear wheels and a couple of cross stretchers plus the brake shaft all lie under the ashpan.

The full size ashpan looks like this - looking at it from the back.


IMG_5540_big by malcolm brown, on Flickr



The first thing was to make a cardboard model and try it in place. After about three attempts, I made one that could slip in from the rear with a bit of tilting. My ashpan is a little shallower than the real one, but I shall give mine a drop door in the bottom so it should be easy to empty it. The "double triangle" bends in the sides give a shallow angle at the front to clear the wheels and then a steeper angle at the back. It is as per the prototype although it doesn't show all that clearly in the photo above.


20240107_142553 by malcolm brown, on Flickr


The sides were cut from 18 g steel using the cardboard model as a template.  To get nice clean bends in the metal, I cut a shallow V groove along the line of each bend, using a small home-made V cutter ground up from the stub of a broken carbide drill.


20240107_151055 by malcolm brown, on Flickr


Then the bends were put in, adjusting until each was a mirror image of the other. Then the front bottom plate and the rear upper end plate were added, made from 1/8" steel to give rigidity and allow it to be assembled with 10 BA screws. In due course, the permanent joints will be silver soldered. It still needs the front and back dampers adding, plus the drop door for ash disposal.


20240107_181055 by malcolm brown, on Flickr


That's all for this weekend.

Best wishes

Malcolm

[mbrown]

Ashpan complications...


The ashpan has made reasonable progress since my last post, but I had problems finding a way to empty it. My original idea had been a drop door, and I duly made one, only to find that however it was orientated, it fouled either the rear axle, a frame stretcher or the brake gear. I toyed with the idea of two flaps but the only way they could work would be if they swung in opposite directions, butterfly-style - and that would need a fairly complex mechanism for which there wasn't really room.

As you can see from the photo below, there's not much room down there for any mechanism. This is looking from underneath, with the front of the loco uppermost and the ashpan, without it's drop door, visible behind the rear axle. The ashpan does actually sit equidistant between the wheels when the loco is on its wheels and the ashpan fixed in place.


20240120_143539 by malcolm brown, on Flickr


In the end, I worked out that there was room for a sliding trap door, which could (almost!) be slid out toward the rear. However this would just foul the rearmost stretcher. I didn't want to remove the stretcher to cut it down (by about 3/32") as it is bolted to both frames and two other stretchers - removing it would amount to completely dismantling the rear of the loco. So after some head-scratching, I worked out a way to trim it in place.

Coincidentally, the T slots on my milling machine table are 2.5" between edges, so the loco can sit on the mill table as if on rails and level. I put a suitably sized bar of steel under the frames and bolted the whole chassis down firmly onto it with two T bolts and bars as below.


20240120_154942 by malcolm brown, on Flickr


The stretcher to be trimmed is marked with blue prior to scribing a line to show the depth of cut. With a long series end mill in the chuck, the job was done in a very few minutes - although I did have to reposition the right hand T bolt to allow the chuck to get near enough. The stretcher was made to the dimensions of the prototype, but  they empty their ashpan the hard way with rakes from below!

The reduction in the height of the stretcher gave me clearance for the sliding ash door and now I just have to mount the ashpan properly and rig up the damper levers.

More tomorrow.

Best wishes

Malcolm

[mbrown]

Ashpan completed


The ashpan is now complete. As I don't want the rear damper handle to get in the way of the slide-out grate, it can't sit in the middle of the cab floor as on the prototype. And the front damper linkage is complicated even in full size. So I am leaving the linkages until I have a better idea of the cab layout. The damper doors are silver soldered to the hinge rods which, in both cases, is extended to take an operating arm which should lie close to the frame where it will be accessible and not interfere with anything else,

Here is the front with its damper -


20240121_140825 by malcolm brown, on Flickr


- and here is the rear. You can also see the slide for dropping the ash - I have left a tab at the rear so that it can be reached and will probably put a hole in it so that it can be pulled back with a bent poker.


20240121_140949 by malcolm brown, on Flickr


When it was assembled, I left it for a few hours in a weak solution of phosphoric acid. This got rid of a few rust spots on the steel plate I used, and gave the whole lot a grey patina. I hope this may keep it rust-free, but it also, in my opinion, looks better when glimpsed through the frames than bright steel (or rusty steel, come to that).


Finally, here is a rear view of it installed. The gap between the ashpan and the foundation ring allows the grate to be withdrawn as in a previous post - and it will be filled by a removable plate after the boiler cleading has been fitted.


20240121_144041 by malcolm brown, on Flickr


So, another stage finished. What next? The boiler cleading, or make a start on the valve gear, I guess.

Best wishes

Malcolm

[mbrown]

Mudhole Door casings

Very prominent on the back plate cleading in the cab of 99 3462 are four mud holes set in quite deep casings let into the corners of the cleading - see below:


dsc_31229qjhl by malcolm brown, on Flickr


These are quite a complex shape and I am not sure if I have got it quite right, but I had a go today.

I started with a length of 3/4" dia x 1/16" brass tube, split longways and notched each side.


20240127_161917 by malcolm brown, on Flickr


This was annealed and bent together until the edges of the cut outs met (I needed to put a few slivers of brass in the gap as it couldn't close completely) and a short piece of 5/16" dia copper tube was scalloped to fit the resulting depression and secured temporarily with a screw and strongback. This was all silver soldered together.


20240127_163925 by malcolm brown, on Flickr


Then the corners were cut back - which was tricky as the things is very difficult to hold - and a small steel strongback with an 8 BA screw and nut added to represent the bar securing the internal mudhole door.


20240127_172734 by malcolm brown, on Flickr

This will eventually be soldered into the backhead cleading and fitted to the cleading around the firebox. The half-tube didn't quite leave enough material to get into the corners, but I don't think this will matter as the gaps will be filled by the angles securing the cleading on both edges and, in any case, I have left the edges a bit long so that they can be cut back flush with the cleading later.

Now I need to make three more for the backhead, two rather different ones for the top of the firebox and two more, different again for the front corners of the foundation ring. It was quite time-consuming, but I think it should look the part.

Best wishes

Malcolm

[mbrown]

Back Plate Cleading


I have made a start on cleading the boiler by making the sheet to cover the back plate. For rigidity, I have made it out of 1/16" brass sheet - starting by making a cardboard pattern and opening up the holes in the brass with a Cone-cut. It fits very neatly over the boiler bushes. There is a gap around the regulator bush as the quadrant is carried on a ring which surrounds the bush.

The scallops have been cut out for two of the mudhole door casings, there is a dummy wash out plug under the regulator, and an oval cut out which, in full size, revealed the boiler identification plate. I shall probably sweat a dummy plate behind the opening. With the large cut out for the fire hole and its operating mechanism, I think the decision to use fairly thick sheet is justified. There is an angle around the edge for fixing the firebox cleading plate.


20240128_175246 by malcolm brown, on Flickr


That's it for another week....

Best wishes

Malcolm

[mbrown]

Mudhole doors continued.

After several weeks with no workshop time at all, it was good to get back to the bench today.

Continuing with the back plate cleading, the washout plug above the firedoor is soldered in, a ring has been put inside the firehole opening to close off the gap left by the lagging, and the bolier identification plate has been faked with the boiler number stamped on it.

The pockets for the mudhole doors have been sweated into the edge - a tricky job that - and trimmed to size. The strongbacks which in full size hold the doors tight are made and ready to be added. There is still a bit of cleaning up to do,


20240303_175901 by malcolm brown, on Flickr



At the front, the throatplate cleading has two cut-aways for mudholes at each corner, as below.


DSC00489 by malcolm brown, on Flickr


I didn't want to drill into the boiler to fit dummy man holes, so I made new corners for the throatplate to mount inside the cleading and outside the boiler itself.


20240303_164349 by malcolm brown, on Flickr


They needed a bit of cutting away to clear the expansion brackets, but they should look the part.


20240303_175738 by malcolm brown, on Flickr


Next job is to use card to make the firebox cleading and position all holes etc, then cut it out of brass and screw it all together, followed by the boiler barrel cleading.

Best wishes

Malcolm

[mbrown]

Firebox Cleading - and an insulation query


The rest of the cleading for the firebox is finished. The prototype has two large manholes on the shoulders of the outer firebox wrapper and, although they are in the cab, they are quite prominent so I have reproduced them.


dsc_3123bxkqr by malcolm brown, on Flickr


I also made the two washout door seatings which sit over the top front corners of the inner firebox.


20240310_175100 by malcolm brown, on Flickr


20240310_174857 by malcolm brown, on Flickr


I haven't yet added any insulation between the boiler and the cleading. I have some Kaowool which is about 1/8" thick and which is compressible to fit in the tighter places. However, I read ages ago that a layer of aluminium foil added significantly to the heat retention - I think it was in Bill Carter's account of his Dukedog loco. It would be easy enough to put a layer of foil along with the kaowool - but I am not sure whether it would be best next to the boiler or next to the cleading. I also seem to recall from O Level Physics that the properties change according to whether the shiny side or the dull side is facing the heat source... Can anyone who, unlike me, remembers their basic physics, shed some light on the question?

Best wishes

Malcolm

[nonort]

As an side if the Foil is compressed against either the cleading or the boiler i.e. no air gap I doubt that it makes any difference at all. The shiny side will only reflect heat if there is an air gap however small. If its placed next to the cleading surely it will immediately transfer the heat to that Aluminium being a good conductor of heat. We seem to forget that modern paint will stand higher temperatures than that of old. Air that is trapped in the lagging is probably the best insulator similar to the effect that occurs in double glazing.

[mbrown]

Bits and pieces


I haven't been entirely idle in the workshop for the last few weeks, but finishing the boiler cladding meant tackling various other bits and pieces first while the boiler was off the frames.

The firebox cleading also needed a good deal more work despite appearing complete in my last post. The throatplate cleading wasn't fitting properly around the bush for the blow down valve - it transpired that the bush was not exactly central and that, when making the cleading plate, I had measured accurately but then managed to reverse the plate. By this point, the plate couldn't easily be reversed again, so I had to open out the hole quite a lot to get it around the bush. That was unsightly, so I made a crescent-shaped infill which is soldered in place. It is actually smoother than it looks in the photo.


20240413_192122 by malcolm brown, on Flickr


The cleading over the firebox had to be cut away rather drastically to clear the reverser stand, although the effect when painted should be to look as if the reverser is bolted to the boiler as in full size. But the backhead cleading created two new problems: the clip which supports the grate had to be re-made as the operating pin fouled the cleading. I re-made it to be operated by a small hook like the ashpan door.  I added a shouldered pin on the right so that the clip engages with this to prevent the clip drooping. The photo also shows how I have cut off the cleading plate a bit above the foundation ring so that the boiler number, pressure details etc. are visible when the door (yet to be made) which closes off the gap above the cab floor is removed.


20240413_190913 by malcolm brown, on Flickr


The other problem was that the regulator quadrant is fitted to the regulator bush with a 6 BA grub screw - but this ended up just behind the cladding plate so couldn't be reached with an Allen key to tighten it. The solution was to drill a hole down through the cleading sheet - but the position meant this had to be done with a 3/32" end mill as it needed to cut into the fixing angle and the plate itself. Here is the hole...


20240413_153116 by malcolm brown, on Flickr


This, however, cut through the top rivet which held the angle in place and left a small hole. I covered this with a small strip of brass and two rivets which represents a small brass plate on the prototype's backhead which reads "Stahlfeurbuchese" - i.e. Steel Firebox. I don't know if this was present in DR days, and I doubt if I will even attempt to engrave the word on its as the plate is only 1/8" deep. But it is at least in the right place as the two shots below show.


20240413_181904 by malcolm brown, on Flickr


40540771_291950111595205_7859561320117436416_n by malcolm brown, on Flickr


The firebox cleading is lined with one layer of Kaowool blanket. With so many cut-outs, and the blanket being rather flimsy stuff which is easily torn, it is fixed to the cleading plates with a few dabs of Evostik. The boiler barrel itself is 4" dia and the diameter over lagging needs to be 4.5", so the barrel has two layers of 1/8" Kaowool balnket. To keep it roughly in place prior to fitting the cleading, I used 15 amp fuse wire.


20240413_165103 by malcolm brown, on Flickr


While the boiler was off and separate form the smokebox, I drilled the smokebox for the snifting valve and the external blower union - both these fittings can be made soon, I hope. I also fitted the whistle in the one space available between the frames. It is an old Metropolitan Police whistle with a union soldered into the mouthpiece. The diagonal orientation gives a better pipe run than having it running fore and aft - it is also the only way it would fit!


20240401_183459 by malcolm brown, on Flickr


Next steps should see some more visible overall progress.

Best wishes

Malcolm