With the weather not really being conducive to opening workshop windows and doors to try a test run of propane and paraffin fueled engines, I slipped in another little one.

This time it is my version of an old Bassett-Lowke twin cylinder oscillating engine, probably from the late 20s -302 that I came across an image and photo of. If anyone has an old BL catalogue with this in or even one of the originals, I would be interested to see what you have as I have not been able to find another on the net.

As usual I drew it up in Alibre in my preferred metric sizes which came out at 11mm bore x 12mm stroke.

I also got the frame for this one (and something else) 3D printed in Aluminium by Craftcloud. Again I’m very happy with how the print came out, the bead blasted finish did not need touching so better than any castings I’ve had.

I did not take a lot of photos of this one as a lot of it is much the same as the previous two wobblers that I have recently described but here are the few I did take.

I included holes in the print which helps keep the cost down, they just needed opening up with a 0.2mm undersize drill and then reaming. The face of the bearing pockets and port faces also had the 0.5mm machining allowance I had included milled off. The material cuts fine with an aluminium specific carbide milling cutter though HSS would do just as well.

The 24mm diameter flywheel/crankwebs were cut from 25mm steel, reamed and the recesses cut on the CNC

Cylinders were from some scrap cast iron, milled to overall size, bored and the rounded end turned before going back into the mill for the pivot and air holes. The outside was rounded in my usual way of milling faccets and then blending with a file.

A HSS spindle moulder cutter was pressed into service as a form tool to round the cylinder top caps

For a change I decided to make the pistons and their rods as a single item from 6082 rather than a separate stainless steel rod. Just a couple of oil grooves on this small one.