I couldn't put the day off any longer. It was time to relearn how to use a lathe.
This one, to be precise. It's been lurking in our large shed for years, just biding its time. The first job was to clean it, as whoever had used it last - hard stare at Best Beloved - hadn't bothered to clean up the swarf and excess cutting fluid. To be fair, that was probably not a bad thing. Although the shed is quite dry, there was evidence of some surface corrosion, and where things had been left mucky had helped prevent it. Anyway, the photo is the result of a good brush down, vacuum cleaning, and a gentle buff with some 3-in-1 and wire wool.
Earlier I had chopped up 5mm brass hexagonal bar to roughly 45mm lengths. I even treated the junior hacksaw to a new blade for the job! What is this all in aid of, and what has it to do with broad gauge coaches? You may well ask.
I may have alluded to building these four eight-wheeled rigid underframes as pseudo bogie coaches. The BGS provide an underframe kit, which is intended to let you build a sort of compensated radial truck affair. Learning from the experience of others, and on recommendation of Alan Garner, former chairman of the BGS and long-time model railway acquaintance, I decided to build proper hidden bogies designed as inner frames. The idea was used by Alan, based on a design by Trevor Hughes which appeared in MRJ 78. Alan's write-up was published in the BGS journal No 69, Spring 2013, and it his dimensions and materials I am following.
So, the hex bar is for the bogie pivot and centre spacer. The job for the lathe was to clean up and square up each end, skim the bar to 44.5mm long, or as near as my usual measurement skills can manage, pop a centre mark on each end and drill a little way in with a 1 or 1.2mm drill. I won't go into the bogie design details yet, as I hope it will become clear in due course.
Here we are, ready to square up an end. Ideally, there would be less of the work sticking out. I have the wrong chuck in the machine, which previously has been used for reprofiling wheels, using the tail stock and various bits and bobs. This chuck won't let the work poke all the way through, and for some reason my tutor today, Best Beloved, felt it was too much effort to fit the proper one. Let's just say we got away with it, and have agreed to install the other chuck for future work!
The first stage was to square up one end of each of the bars. I ought to sort out numbers for you: four coaches, two bogies each, that's two bars per coach, eight bars in total. I cut two off two spare lengths to allow for the inevitable visit from Captain Cockup.
Once I had been through and trimmed one end of each bar, we set up the tail stock to centre pop them.
Next, I applied marker pen to the untrimmed ends. You can see the only breakage I had today - my thumbnail!
Setting the digital vernier calipers to 44.7mm - I know I wanted 44.5, but I don't think 0.2mm will make all that much difference - I did the naughty thing and used the sharp bits to scribe the length I needed to trim to all round the bar.
Then I was ready to begin again. It took a while to get my eye in, but eventually all the bars were trimmed to near enough the correct length. Once squared up, the ends were centre popped, then it was time to drill.
Swapping the tail stock for the one with the drill chuck, a 1.2mm drill was used to make a hole in each end about 2mm deep.
And there we are. Time to clean the lathe, ready for another time. I only lost one bar to error, which justified making a pair of spares at the start!
My next job is to work out how to mark up, cut out and drill a dozen identical side sheets from NS sheet…