This is a photo diary recording the build of a model of an OMC-2 Beam Engine built from the Old Model Company kit. The kit was ordered via the Old Model Company website and it arrived safely a couple of days later.
4th October 2008
The first step was to check all the components off against the parts list supplied, Iím happy to report that nothing was missing. The instructions were then read through carefully a couple of times in order to familiarise myself with the building process.
The wooden base was marked out and drilled with the aid of the template supplied in the kit. The base was then sanded smooth and given its first coat of varnish. When thoroughly dry it was lightly rubbed down with steel wool and a second coat applied.
I decided that, like the Froment engine I built last year, the flywheel of the beam engine would have painted spokes and a polished rim. Ordinary enamel paint does not adhere very well to brass so the wheel was first primed with a specially formulated etch primer. This will be allowed to dry thoroughly before the gloss top coat is applied.
Time to get the polish out! A start was made today polishing some of the turned brass components. I use an American metal polish called Simichrome, it is the best metal polish that I have ever found and is highly recommended. Itís not easy to find in the U.K. but try searching on ebay.
Once the varnish on the wooden base had had a couple of days to harden, the four electromagnet coils were fixed in place.
Some further progress yesterday, the platform sub-assembly was constructed. This fits over the coils and is fixed to the base.
The crankshaft base plate was fitted to the base, together with the two brass pillars that support the crankshaft. The old model company thoughtfully supply a mandrel in the kit to aid this assembly. The mandrel is a few thou. larger in diameter than the crankshaft so once everything is
tightened up the mandrel can be replaced with the crankshaft, which will be perfectly aligned. The substantial brass pillar that supports the beam was also added.
Only time for a quick job today, the rocking armature was fitted.
A rocking motion is imparted to this armature when the two pairs of coils, that are energised alternately, attract it.
A connecting rod will be attached to the armature to drive the beam up and down
First task today was to polish the two halves of the main beam and also the two connecting rods.
The connecting rod that is attached to the rocking armature needs to be bent through 90 degrees. A very sensible suggestion in the instructions is to make a 45 degree bend towards each end of the connecting rod. This lessens the bending stresses and minimises the danger of any breakage. The photo on the left illustrates the two connecting rods
Next came the assembly of the main beam. This is simply a matter of bolting the two halves together, although I must admit that the 10BA nuts can be a bit tricky to handle due to their small size. However, the kit does include spares in case one gets lost!
The beam was then fixed to the pillar and everything was checked to ensure it was square. The two connecting rods were then attached to the rocking armature and the crankshaft respectively. The flywheel was temporarily fitted, it still needs gloss painting and polishing.
First task today was fitting the camshaft to the crank axle. Once this was in place some minor adjustments were made to the alignment of the beam to ensure everything was running smoothly with the minimum of friction. Next the interrupter contact units were assembled and fitted to the crankshaft base plate.
This afternoon I made a start on the wiring. As this is mainly under the base it needs to be done with the engine inverted. The box, in which the kit is packed, converts into a jig that allows the engine to be securely mounted upside down. This certainly makes the task a lot easier.
Nothing much to photograph today, some more wiring and the flywheel was given its final coat of gloss paint. When the paint has fully hardened the rim will be polished.
This morning the painted and polished flywheel was mounted on the crank axle and the assembly of the engine was complete. It was connected to a DC power supply and ran beautifully, only a couple of minor adjustments were required in order to optimise the performance. I am absolutely delighted with the finished engine.
I ought to repeat the disclaimer that I have no connection with the Old Model Company other than as a highly satisfied customer. However, I can highly recommend their model kits to anyone looking for an interesting and very enjoyable construction project.