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.
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.
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.
Further progress on the tender has seen the basics of the body
So far, the only issues have been some bowing of the half-etched
sheets which has taken a bit of work to get them soldered up straight. The
worst being the rear sheets with the steps and the coal door.
In the end I added a second sheet of 10thou nickel to back
off the coal door.
With the brake hanger height sorted it was time to fit them.
Because the wheels are on telescopic axles, they need much more wiggle room to
be removable than the Slaters et al, types. It’s actually quite surprising how
little room you need to remove a Slaters wheel.
The lack of space around the brakes meant that for the
wheels to be removable the brakes need to be removable too. I did this by
adding a collar from microbore tube over the .9mm rods that the brakes hang from
on the frames. And at the moment the cross shaft at the front of the tender is
removable but I am sure that if this were fixed the brakes would pivot out of
the way to get the wheels out.
Just to prove that they are removable.
I also made the two quite hefty support rods for the water
Plus, a Blue Peter moment in that here’s one I did earlier.
I fitted the brake cylinder that I turned when I first got the Unimat 3.
A few general shots of the inner chassis, for no other reason than I got a bit carried away with the camera.
The next interesting bit of the build was when I came to look at fitting the brakes. The kit provides etched brakes for the tender in the usual dual layer fashion. I had some nice casting from the Hobby Horse Reynolds range. They were the ones that I was drilling out when I showed my use of pliers to clamp them for drilling a short while ago. When I put some rods through the chassis in the holes provided and dry fitted the Reynolds castings to the stretchers and pull rod frame they wouldn’t fit because they were not long enough. After a bit of head scratching I checked the drawing and sure enough they are to scale length. However when I checked them again the etched ones provided it all made sense.
The answer to this little dilemma was to re-drill the holes in the frames 1mm lower down. There was just enough frame depth to do this without having to resort to adding hanger brackets.
When I started on the brake pull rods and fitting the water
scoop, I quickly realised that the kit is very lacking in detail underneath the
After being kindly supplied a drawing that showed the detail
of the inner frames of the tender, I started to add some additional details. My
spares box yielded a couple of balance weights which I added to the linkages
supplied in the kit. Not perfect but better than nothing. This is still a work
As you can see from the photos it does all move at the
minute but I may need to solder it solid depending on how far I can go with the
remaining linkages and how controllable they are.
I also started work on the brake linkages adding a bit of 3D detail to the joints using scrap etch and brass rod.
It’s time for another weekend project to break cover. Another of my outstanding jobs is the build of a David Andrews LMS Princess Pacific kit. The Loco is to be 6206 Princess Marie Louise depicted in the late 1930’s. I was pleasantly surprised upon examining the box contents, that the gent that I am building it for had ordered all nickel etches. 6206 was slightly unusual in that for much of her life she was attached to a tender equipped with a coal pusher. The additional parts for this have been supplied by Finney7 from their Duchess tender. The box also contains a lot of additional extra castings to upgrade the kit parts.
The wheels are Alan Harris castings turned by the gent that I am building it for.