Moving swiftly along from the brake standard modifications. You may recall that some time ago I made a stove for the brake van using my Silhouette cutter. Although I proved it was possible, it was extremely fiddly to assemble and I certainly wouldn’t want to be doing a lot of them.
It’s also a perfect candidate for 3D printing so yesterday morning (after amending the brake standard files) I started to draw up the stove.
It has proved to be my most ambitious and ultimately satisfying design project to date.
My apologies for the image overload but I am delighted at how well it has turned out.
Looking to start adding as much as I could details wise, before
assembling the main components. I dry fitted the tank filler and the vent pipe castings
on the tank top plate. Although the latter are generally not bad castings, when
I opened out the etched holes, they both sat lopsided. I attempted to tidy them
up using a square needle file but wasn’t able to correct the lean.
I decided to have a go at turning them, but gripping them to
turn them in the lathe was going to prove interesting. So, I took a leaf out of
the late David Smith (DLOS)’s book, and made a split collet from a length of aluminium
I had recently watched a YouTube video of someone doing just
that and the guy who made the video had left a collar on his split collet to
make it easier to get it in and out of the lathe collet.
This shot shows how the casting sits in the split collet.
You can see in the shot below how lopsided the base was. The
rim of the base plate was so thin that I dare not turn too much off or I would
have ended up having to turn a collar to replace it. Which was plan B if I hadn’t
been able to get the existing base plate to sit flat
Thankfully I got away with it and didn’t need to resort to plan B.
The recent hot weather has somewhat killed my enthusiasm for actual model making so instead I have been drawing up a few more bits and pieces. Some of them are still work in progress but I finished an LNER Brake standard last night.
I have long wished for a correct LNER brake standard casting so now assuming that it prints okay my wish should be fulfilled.
Modelling time has been in short spells just recently, hence
my lack of posts. I have been beavering away at detailing the front and rear of
the tender but I haven’t taken any photos yet. However, a discussion on the
Guild forum about details of the coal pusher fitted tenders had me looking
closely at the drawings of the modifications done to the 9 Ton tender to
increase coal capacity to 10 Tons. There are drawings of the upperworks in LMS
Profiles no 4.
The tank vent castings cleaned up quite nicely by spinning
them in the mini drill with a bit of scotchbrite and although the water filler
was a reasonable casting, when comparing it to the drawing it’s a bit on the
undernourished side. So, using the same bar as I used for the eccentrics which
was just the right diameter, I decided to make a replacement. I had a look at
as many photos as I could find and it seems that David Andrews has the type of
hinge mechanism pretty much correct albeit that all the ones that I saw had
plain straps without visible fasteners.
After turning, I transferred it to the mill and used a
recently acquired edgefinder (less than £7 posted from Allendale) to help to
accurately position the holes. I then used a 1mm collet to hold a .06mm drill and
away we went. Fitting such small drill bits into a collet on the mill is a bit
of a fiddle and you could really do with another hand but it’s worth it.
Although I dressed the backhead a couple of weeks or so ago, I hadn’t managed to get it to fit into the cab before now because the stub of the whistle protruding through the cab roof stopped it from sliding in. One of those little few minute jobs that seem to take forever to get around to…. I finally got to it and the backhead now fits in place as if it was made for it.
Following the visit last week of the Volker Rail Beaver 1900 Tamper surveying the line last week (photos above) we have had several visits this week from a Volker Rail 2004 and today we had the chance to really get up close and personal as it levelled the line at the back of our house. What a fascinating machine to see in action.
We had something a little different down the branch this afternoon or rather it went up the branch last week but I only caught sight of the rear cab window as it disappeared out of view. We thought it odd that it didn’t return (usually most ‘trains’ go up the branch and return the same day). We have had quite a bit of works train traffic on Monday’s of late but much of it has been seen before so I haven’t posted any photos.
They look to have been working their way back from Redmire surveying the branch because it had already passed our house on the way to Bedale when I became aware of it and popped up to take a look. By good fortune it had stopped a couple of hundred yards away and after marking up the ground, (when the machine made a series of loud beeps) it then reversed to about 20 yards beyond the house on the Redmire/Leyburn side. More beeps more marking up and it reversed direction again heading back off towards Bedale. I reckon it must be sat in the passing loop at Bedale station now, because just before 5pm we had the Class 20 featured previously, come past light engine heading to Leyburn/Redmire.
For those it might interest, there are more details shots on my Flickr site
After spending a week teaching myself 3D drawing, I was back
at the workbench today. I had originally planned to just turn a couple of
appropriately sized top hat bushes, file some flats on them where they come together
and job done. My recently acquired mill offered more possibilities to make
something that at least looks like the original even if it doesn’t attach in
the same way. This will be soldered to the cylinder front in between the slide
bars, instead of being suspended from a substantial bracket between the frames.
This is my first real item produced with the mill and I am
happy with how it turned out.
This is where it will sit in between the slide bars on the cylinder front. I have added some fastenings to make it look as if it should be there, when it’s ultimately lost in the gloom between the frames.
At the risk of boring people with my new found skill I have drawn up a couple more items yesterday. First was a much simpler task than the chimneys that I have drawn so far, this time a dome for the D2.
Then at a friend’s suggestion I had a go at the GNR version of the Ramsbottom safety valves.
I had got this far when Chris looked over my shoulder and said “it looks good but it doesn’t look right” she was of course correct the springs should be on the lever that I hadn’t drawn yet not the valve stems… To be continued…
The D2 chimney must have been beginners luck. The next one took me two days of fighting to get it finished. Despite the frustrations I have learned much from the experience (I am a great believer that mistakes and things going wrong are far better teachers than when things go swimmingly).
This chimney is for non condensing C12’s and J52’s. According to the drawing, the condensing versions were fitted with shorter but otherwise similar profile chimneys. I feel that I have done a better job of this one and it’s a bit finer in shape/detail.
I am not sure whether it’s beginners luck but further sessions today have added a tube under the centre of the flare to help locate the chimney in the smokebox and the rivets around the rim. I still haven’t got it completely hollow but I will perhaps try to achieve that on the next one.
You may have seen elsewhere that coming up I have a test build for an LNER D2. The first build is to be a BR period build and I have a J6 chimney casting from Gladiator for it. However once the etches are proved I plan to build a second D2 for myself which I wish to finish as it was in it’s early life with the LNER in lined green.
This means that it will need the original chimney so I need to turn one/have one 3D printed or something. Those who are Gauge O Guild members my be aware that following on from the success of the virtual shows the Guild has been hosting some special interest session in various subjects one of them being 3D CAD/Printing. I missed the initial session a few weeks ago but caught up with it via the YouTube channel and then joined last nights session.
Prior to joining the Zoom session I downloaded and installed Fusion360 which is the software at the centre of the 3D CAD element of the sessions.
This morning I had a play and following a demo video done by a fellow GOG member last year I managed to draw a chimney. Having completed it I shared the image below with the gent who ad created the artwork for the D2 etches and he commented that the smokebox looked a bit narrow. Then it dawned on me that I had used the figure for the radius taken from the drawing and hadn’t doubled it to enter the diameter. Apparently you can enter a radius figure but I haven’t worked out how yet.
So this afternoon I attempted to redraw it using the correct smokebox size.
You will note in the image above that there are orange coloured squares. These are offset planes that I used to apply the dimensions from my chimney drawing. I managed to miss out one of the planes (for the bottom of the chimney rim) and try as I might I couldn’t manage to draw any lines between the planes like I had this morning. in frustration I deleted all but the base, saved it and went and had my dinner.
This evening I worked out how to import a drawing, resize it and then draw over it as I would in Inkscape or QCAD.
Below are a couple of views of the revised drawing.
I went through the process again this time drilling the offset at 2mm which proved to be perfect for this particular application.
I had been using a very thin cutting tool which someone had ground (not very well it turned out) which came in the box of bits with the lathe. After cutting the first one I thought that I would examine the tool to see if I could improve it or at least rub it on a stone to restore the cutting edge. When I looked closely at the cutting part I noticed that the bottom of the tool was wider than the top and although there was some rake away from the cutting edge the fact that it was getting thicker couldn’t be helping to make an efficient cut. This is a sketch of what the tool looked like originally albeit the bottom of the wedge is somewhat exaggerated. [img]https://live.staticflickr.com/65535/51259964196_7d3dd5c448_z.jpg[/img]
I have watched a few Youtube videos on sharpening lathe tools recently so I had a go at grinding the tool to take off some of the thickness towards the bottom making the two sides parallel. This improved the cut and I successfully cut the groove for the first sheave. Then I parted it off but I was a little too close leaving a very thin edge. During the parting off, the parting tool moved slightly in its holder which pushed over the thin rim of the sheave slightly closing the top of the groove. In the end it was usable but I decided to cut another pair to be on the safe side. It was while parting off the first one that I noted that my parting tool was in fact just the right thickness for cutting the groove without having to move the carriage as well as the cross slide to get the desired cut. Having discovered this the next one progressed much faster and modifying the fixture that holds the parting tool so that it grips the parting tool more securely by squeezing it in the vice made the third one even faster still. The parting tool is one like this albeit mine only has one tool. You will note that it’s a pressed steel fitting that grips the part with the aid of a cap screw. Mine didn’t hold the cutting tool very closely to the holder but it does now. https://images-na.ssl-images-amazon.com/images/I/41Uv-fAJmjL._AC_.jpg
So here we have the finished sheaves.
This is how they will fit on the axle once I work out their alignment with the crossheads further down the line.
It turns out that I wasn’t far out with my 16mm deep offset hole, I had a measure of the remaining stock while putting this post together, and there is just about enough material to cut a 4th sheave had I needed a full set for a conventional inside motion build.
Although these parts are allied to the Princess build, I thought that I would add the making of them and the reasoning behind it as a separate post just in case anyone has need to solve a similar problem in the future.
Readers of the David Andrews Princess thread will
have noted that I had to make the brake gear removable to ensure that I could
remove the wheels due to them being mounted on telescopic axles. This need
stems from a similar issue but I will start at the beginning.
Although the gent that I am building it for doesn’t
want full inside motion. One thing that is quite visible through holes in the
front frames, is movement of the crossheads. I was asked if I could add some
element of movement using the spare outside motion bits from the kit ( a set of
Premier rods etc. has been supplied for the build). Having started to think
about it long before getting to the actual start of the build I realised that
with the axles being hollow I couldn’t use traditional cranks to make the
crossheads move (or rather I wasn’t comfortable that I could make it work
without ruining axles wheels). So I thought that a pair of eccentrics would
impart movement while being able to be attached to the hollow axles without
having to cut them.
We agreed this as the way forward and I ultimately
bought castings for the slide bars/crossheads and eccentric straps from Laurie
Griffin. I was also going to buy some eccentric sheaves too until I recalled
Nick Dunhill finding the new cast versions very time consuming to prepare.
Further thought made me also realise that the LG cast ones wouldn’t really work
anyway. This is because in a ‘normal’ inside motion set up the eccentric sheaves
are trapped between the cranks so the eccentric straps cannot slip off the edge
of the sheaves. Of course, I planned to use them as a single eccentric so they
would need to be restrained at either side.
Instead of ordering a set of cast eccentrics along
with the other parts, I bought a length of 12mm round brass bar instead.
Initially I was going to offset in the lathe using
a four jaw chuck to offset the bar but having done a bit of research online,
most machinists were of the view that you could but if you had a mill it would
be far easier to drill it in the mill. Not being as proficient with my mill as
I hope to be in time I did use the lathe to put a small centre mark in the end
of the bar before transferring it to the vice in the mill.
Then using a centre drill inserted into my centre
mark to centre it quickly, it was easy to plot the offset (2.4mm, more on this
later) and then drill it out to 4.5mm. I then took it to final size with a
Transferring it back to the lathe I took a skim off
the outside and marked up for the first sheave. Some time later we had this.
I tried the
eccentric strap for size and found it was just a little too wide for the strap
to close completely around the sheave.
It was at this
point that I noticed that the depth of cut of the groove to accommodate the
strap was such that it was very close to breaking through into the offset hole.
It seems that in setting my offset hole at 2.4mm from the centre to gain the
maximum amount of movement was just too much.
You may be able
to see the mark where it’s just about to break through in the image below. This
was made worse by having to apply a second slightly larger reamer than 3/16
(4.74mm) to get the axle end into the offset hole
The plan is to
start again from the other end with a 2mm offset hole and see how I get on.
Yesterday saw more progress on the motion for the J6, with the valves almost complete.
I still have the arms to make that connect the valve rockers with the expansion link etc. But I am pleased that I have got this far as I had hit a bit of a mental brick wall with concern that attempts at soldering on the valve rocker supports would result in them dissolving into individual parts again.
As happens often when procrastinating, I worried for nothing.
In my varied kit collection I have a few items of NER rolling stock from Medley Models/NER Days and it recently came to my attention via a fellow modeller that among other things the buffer heads in some of the kits need a little attention. I had a vague recollection of Steve Hoyle mentioning something about his supplier having supplied them as they are and has subsequently passed away so no chance of doing anything about them. These are what came with some of the kits (appologies for the slightly out of focus photos). You will note the interesting collar that would prevent any kind of compression…
I bought a couple of B1 opens from Mossy and they have been sat on my desk with the buffers beckoning to me each time I sat at my laptop. So this afternoon I decided to turn the collar off. In the end I did about 30 and it was quite a good exercise in repeatability on the lathe using the graduations on the lead screw handwheels although the minor variations in sizes proved that they weren’t done with a CNC machine. I also took the opportunity to file off any centre pips and rub over the heads with emery while I had them in the chuck.