Well, up until a few months ago, I would have said that I'd probably never build an oscillating-cylinder steam engine. That was before I saw the little Cracker locomotive win April's Project Of The Month over at the Home Model Engine Machinist forum.
The winner was a guy that goes by the board name of "Shred", and his write-up and photos of this little 16mm-scale (G Scale Locomotives runnng on O-Gauge track, representing 2-foot gauge on the prototypes) were more than enough to convince me I needed to build it.
The plans are available for free in several places online, ( http://home.iae.nl/users/summer/16mm...ms/Cracker.htm ) and before long I had printed them out and was planning to build a PAIR of these little utility engines.
Here's my progress so far.
The first thing I had to do was come up with the gears, as the pitch diameter would set the axle and crankshaft spacing. I followed Shred's advice, and used RC pinion gears from Robinson Racing, as I've used their products many times in my younger days.
Cutting out the side frames was simple enough, and I decided to build TWO locomotives, one for myself, and one for my dad, who's fuelled my interest in all-things-mechanical since I was a wee lad.
Here's the first frame side plate being cut out on my little Sherline mill.
This is too easy, so far. The loco frames are 10mm longer, 5mm added to each end, to make room for a slightly longer boiler, and more room on the footplate as well. Originally, I was going to add all 10mm to one end, and move the fuel tank under the footplate and between the frame rails, as I've read elsewhere online, but decided against it, at least for THIS build. ;D
I turned two sets of bushings from bearing bronze, again diverting from the plans, and making all 8 bushings to the same dimensions.
Here they are pressed into place in the frame sides.