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