Disaster - my cranks have fallen off!

It had to happen. After gloating in a previous post about how well Lancashire was running, I moved on to adding the valve gear and con rod to the left side. The valve gear is now built up into thre sub-assemblies and ready for fitting.


LHS gear ready for fitting

So Lancashire took to the test track to limber up before the first stage of adding the rods. And while trundling along happily at low speed, this happened.


Calamity on the test track

Yes, the flycrank has come off. In fact both the fly cranks fell off at the same time. Remarkable.

The closer photo below sheds a little light on what's happened. It looks as though I've soldered on both cranks with only a small amount of solder actually making the connection, resulting in a weak joint. In addition to this, there's been quite a bit of flux left behind inside the crank, corroding the axle. Presumably this has worked away at the joint until there wasn't enough left to maintain the joint. The morals of the story seem to be:

• Make the crank a tight fit on the axle to ensure nothing nasty can live in the gap
• Only add the flux from the outside
• Make sure you get enough solder on to make a proper joint
  

This ain't one going much further...

'Canopus' - disassembly for painting

My Backwoods Canopus has been around for many years and I still haven't finished that either. I've got it to the stage where the chassis is complete and running - although I have to admit it's not very smooth - and the body is complete and just about painted.

Canopus in her present state

The whole thing is designed to dismantle quite nicely into the three major assemblies of cab/footplate, boiler/tank and chassis. I went one step further and attached the tank to the boiler with a 12BA screw to allow it to be removed for painting. This is great until any strain is put on the screw - in my case it to was due to a child-related incident...

The problem is that tapping into whitemetal isn't a great idea, as it works well initially but wears quickly if you take the screw in and out a lot of it or if the hole was a bit too big when you initially drilled it - in the latter case there's not much thread on the whitemetal to start with and it quickly wears away. In my case, a shock to the thread managed to strip it completely.

Canopus boiler and saddle tank

In the photos you can see that I've added little tapped 12BA brass inserts to the two tapped holes, one in the end of boiler weight where it's attached to the cab, and and one in the bottom of the tank. These are glues into tight-fitting holes with cyanoacrylate ("Dr Mike's", in this case). These are turned up from scrap brass and tapped 12BA, but you can do it easily enough without the aid of a lathe by using a 12BA nut or a length of brass tube tapped 12BA. The tricky bit is not getting the glue into the threads, but you can avoid this by lightly oiling a screw and running it into the thread, then cleaning off any oil on the outside before glueing it.

Cruel front-end enlargement

Quartering jig parts

For those who appreciate blurry photos of bits of brass, here's one of the quartering jig parts.



They are (top to bottom)

1. Top - 2mm mild steel drilling jig. All the other parts are drilled from this and it's what gives the jig its accuracy.
2. Row of 6 brass spacer bobbins. The inner two are the smaller back-to-back spacers, the outer four are to space out the crank locating plates.
3. Left side - two 2mm silver steel rods tapped 8BA to clamp it all together
4. Centre - left and right are the 2mm steel crank locating plates, centre are the two brass supports for the axle - note the cutout at the top.
5. Bottom - two 3mm silver steel rods - these are a fairly tight pushfit through the various plates and allow it all to line up consistently.
   

Lancashire's Boiler

I'm having some difficulty in getting Lancashire's boiler, firebox top and smokebox to line up. The firebox top casting (see first photo) fits between the tanks and makes contact with the top of the brass boiler, but there isn't really any room to make a positive connection between firebox and tanks to ensure that all is level and square.


Boiler parts

So I produced the jig seen inside the boiler using some old bits of brass (and a huge lump of 1/2" silver steel - don't ask what that was intended for). This also involved drilling a 2mm hole through the length of the boiler weight. The whole lot was strung together on a bit of 2mm silver steel threaded 8BA at the ends (yes, like the Quartering Jig - I'm not wasting my new 8BA die) which clamps it all up solid. The idea is now that I can create something to hold the whole lot steady within the body while the smokebox and firebox top are fixed in place, leaving the rest all nicely lined up.


The boiler on the jig


The jig in all its glory

Selling The Quartering Jig?

It's been suggested that 009 Society members could be interested in a commercial version of the quartering jig I built for "Lancashire" . If I produced one it would not be exactly like this but would be adjustable for different axles diameter, axle lengths, etc.

This is definitely not a promise to produce such an article, but could anyone who would be interested let me know by a comment on the blog or an email to me?

Modifying Lancashire

My Backwoods "Lancashire" has a number of modifications from the original. Some of these are because I couldn't get things to work, some are because I'm just perverse.

1. Driving wheels - these have been replaced with the more substantial 2mm-axled wheels which seem to be used in most of Pete's 009 kits nowadays. The originals were the old pattern with 1.5mm axles (Alan Gibson? - not sure). I preferred the new ones as they seem to be more consistent and the more substantial axles are nice and meaty, although they do of course require the cranks to be opened out.
2. Compensation - I couldn't get this to work very well, mainly due to lack of patience and an inability to solder properly, and eventually stripped it out and (carefully) fitted the chassis with new 2mm rigid bearings. Replacing the wheels meant I'd have had to do this anyway.
3. Pickups - the kit is supplied with plunger pickups. I think these are also from Alan Gibson. It's a decent setup and I did get it all to work OK, although I ended up with quite a lot of wiring around the chassis. However, the new wheels are live on one side so they were whipped out and replaced with a simple PCB square with a phosphor bronze wire wiping on the drivers at one side. It's mounted on a hefty piece of brass soldered across the frames and tapped 12BA. You may notice in the photos that it has a second 0.8mm hole drilled through both - this is to take a locating pin to stop the PCB wobbling about and causing mysterious shorts (as if that would happen....).
4. Valance - one of the footplate valances is original, the other is a replacement made after its original was destroyed in the making of "Adventures With A Resistance Soldering Unit - why it pays to read the manual". Hint - high amperages can vapourise thin bits of brass.
5. Trailing truck mounting - I turned up a little boss to fit between the training truck arm and the cross member on which it's mounted to allow it to swing freely. I guess a suitable washer/bearing combination would do the same. You can just see it in one of the photos.

The current ensemble from above. You can just see the pickup wiper wires.














The ugly details beneath, in which you can just see the trailing truck mounting boss.










Slightly disorientating shot of the chassis from beneath, showing new wheels and ugly green flux stain where I forgot to clean the pickup mount.

Quartering...

Quartering has always been a real challenge for me. I don't think I've ever built a 009 loco which didn't have a slight limp. I was discussing it with a Well-Respected 2mm Finescale Modeller the other day and his comment was "you've just got to do it - the more you do, the easier it gets". This didn't encourage me. I've had problems in quartering Lancashire for a while, which explains how it's taken me several years to get this far with it. It's run erratically for a while, sometimes having a severe bind and sometimes being almost OK.

So I bit the bullet and built a quartering jig. The commercial ones are no use because they're not designed for outside frames and are mostly directed at 4mm finescale standard gauge, so I had to design something specifically for Backwoods kits with 2mm axles - I wanted it to be just right. The photo below shows what I came up with.

The two centre brass sections have a U-shaped recess milled in the top to hold the axles, and are set the the correct back-to-back by the brass bobbins in the centre. The side sections are 2mm mild steel and have a "L"-shaped cutout in the top to allow the crankpins to be set a to 90 degrees. They're spaced from the centre sections by different sized brass bobbins and the whole thing is kept together with two 2mm silver steel rods with the ends tapped 8BA. The two 3mm silver steel rods keep everything rigid (these are a reasonably tight pushfit into the uprights) - the top one needed a section filing off the top to clear the driving wheel flanges.

As it happens, when I checked the chassis the quartering was only slightly out and was easily corrected . A bigger problem was that one of the cranks wasn't at 90 degrees to the axle - this was replaced. Everything then ran beautifully until I replaced the gearbox and motor, when the bind returned.


At least I'd ruled out the quartering, so after a long period of head-scratching and examination of the running chassis under the jeweller's eyeglass, it transpired that the rear offside driver was slightly out of true with the axle, causing it to bind against the side of the gearbox. Fortunately there's enough play in the gearbox mounting holes to shift it sideways by about 0.5mm without affecting the mesh. Miracle of miracles! - a free-running chassis.