Model Engineering

Once cleaned up by filing, the flywheel can usefully be mounted using the outside of the jaws in the three jaw chuck, and was fairly centrally aligned.  This allows for gently tidying up all the accessible edges of the casting and sizing the hole for the crank shaft.

With that done, I mounted the flywheel on a scrap piece of 9/32 stock to perform the rest of the turning – hopefully that will ensure it’s nicely concentric when mounted on the engine.  With only the setscrew holding it in place gentle cuts are the order of the day, and I’m using my new (to me, anyway) live centre to add support and prevent chatter.

Flywheel in position – starting to look like something now !

Moving on !  Turning the piston to fit neatly into the bored head of the cylinder:

And using the chucking piece to turn the crosshead down to fit into the standard:

Tapping the crosshead for the piston connecting rod – started by supporting with the tailstock to get it concentric, although you can’t see that here:

Using the corresponding die to cut the thread on the piston connecting rod – my pratt burnerd chuck is adequately accurate for this – alternatively a bush to hold the rod could have been made from scrap brass.

Completed assembly – I’ve followed the advice from the Pengwern book – cutting one fairly deep groove in the piston for graphited packing rather than 3 finer oil grooves.