I decided that I would like a square push rod on my engine rather than the round one shown on the original drawings so a length of 4mm key steel was ordered. A spigot turned on one end so that the bronze cam follower could be Loctited to it and the other end was drilled and tapped to take a small threaded adjuster. Rather than fiddle about with a small part in the 4-jaw I just drilled a bit of aluminium to the across-corners distance of the rod, and after sawing a slot down the side. I used that as a split bush.
The engine was screwed to the machining plate once again and clocked in true before finding its horizontal centre line.
I slipped the cam gear and its pivot into place; touched off on the side of the gear, and then zeroed the DRO. I could then set my other heights relative to that.
I could then mill off the excess from the cylinder mounting flange and the rocker pivot bracket followed by a 4x4 slot for the rod to run in.
A few M2 tapped holes for the retaining blocks completed the work that needed to be done in that setup.
The two retaining blocks were just squared up from some off-cuts of brass, drilled for bolts and a small centre drilled hole added for a drop of oil to be applied. I knocked the corners off after the photo with a small file so that they looked like cast blocks.
Another thing I wanted to add to my RLE was a pulley on the non governor side. I will modify the spokes of the cast flywheel to allow one to be fitted but while waiting for those decided to make the pulley.
I have quite a few 5kg cast weights from a multi-gym and although it is not the best cast iron in the world I thought it would do for this job. One piece was cut from one of the weights with my Femi bandsaw and then held in the 4-jaw to get it to the basic shape.
Here the inside has been turned with a 3degree ‘draft’ to the edge. An insert with 0.8mm radius was used to leave a fillet between the inner edge and what will be the mounting lugs for that cast look.
I then held it the other way round in the 3-jaw and machined off the remaining corners before transferring to the Cuts Nice Curves (CNC) machine to shape the mounting lugs and drill their holes.
I probably should have gone 1mm lower with the profile cut as the "step" that can be seen is the fillet left from using the 0.8mm radius cutter.
It was not a problem as I had intended to go over the inner ‘cast’ surface with the Dremel to texture it a bit. Did the remaining fillet at the same time.
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