Hi all,
At the moment I have restricted access to my workshop (long story involving fires and inadequate builders
). I have decided to put most projects aside and build a small oscillating engine and boiler. The engine is based on plans from an old school textbook which I used years ago to introduce students to machining skills and the joy of steam. The engine is intended as a future present for a grandson, he is a bit young to operate or even appreciate it at the moment but I'm sure he'll appreciate it when older. His mother, my daughter admits to being fascinated by a small steam plant we used to run when she was young, so I think (hope) Max will follow in her footsteps.
As he is too young at the moment I have been involved in making toys in another medium for him and I've attached a picture of one of these from Christmas just gone, I hope that you like it and that it's not too way off thread as I know some contributors really hate 'the brown stuff'. The apparent staining on the cab is in fact the heartwood of the Ash that I used, The rest of the cab will slowlly mellow to a similar colour over a few months:
I have not taken any pictures of the processes involved in the steam engine as most of the work is plain turning but I will add some notes if that is OK.
Over view of componentsThe standard to the left is a simple fabrication but what may be of interest is that the standard is dovetailed to the base. It is not a simple dovetail as the socket in the base has a secondary hidden chamfer filed into it. The 'tail' on the standard is made a little too long and when fitted the excess length is rivetted into the secondary chamfer with the ball peen of an engineers hammer and the excess filed away, thus creating 'double dovetail' effect and a very secure joint. However I did also silver solder (braze) it for extra strength but that was not really necessary.
The cylinder is a simple fabrication of brass tube and a flat plate silver soldered with a turned cap added. The piston is made to fit with an oil retaining groove. It was then honed to fit in situ with Brasso metal polish.
The spring is home made from stainless wire on a mandrel in the lathe. The lathe was powered on it's slowest speed (50rpm) and a simple guide used in the toolpost.
The bearing tube at the upper right is first bored at a running fit for the crankshaft, it was then bored for most of its length a few tenths of a millimetre oversize leaving a bearing area at the flywheel end. The standard was also bored to act as the bearing at the crank end so when assembled there is an oil reservoir created between the bearings.
Assembled engine Note the small hole drilled in the bearing tube which is an oil hole to supply the reservoir, I intend to add a small oiler later. The small brass collars are also fitted to act as thrust washers and the one behind the crank acts as a spacer.
The next stage is to add inlet and exhaust tubes to allow connection (probably via home made glands) to the boiler. Cleaning up (AKA 'blinging') of tool marks etc will take place later.
More to follow if this is not too boring - let me know if it is (and I promise, no more of the 'brown stuff' John)!