I thought I had been allowed the Clarkson engine castings but this is what I found when I opened the box in the workshop:
The Rectilinear castings... finishing this engine should be fairly quick and it will give me something to fiddle with when I get bored of flicking over the Bee . Ok so I Normally start at with the base plate:
As you can see someone has already done this for me
Except the cylinder mounting holes are missing. The instructions say drill through from the cylinder cover
Ok back in days gone by you might but I am going to use the DRO's circle bolt function. There are four sets of holes that match the cover: either end of the cylinder, the base plate and a rather nice casting that is supplied for the top cover. So that I can do all the holes at the same setting I will start on that cover.
As you can see it has a steep draft angles (the sides of the circular bits taper horribly) so first up mount it on the large bottom surface and turn something to hold this casting by:
Its running remarkably true
so having rough turned the spigot in the middle and the larger diameter face to get rid of the casting marks time to first turn the centre to the first finished diameter - 16mm this will be the boss for the gland and our chucking piece:
It does not matter what this diameter is but I will be holding it in a collet so I am going for 16mm. I can then face the larger diameter - this is the top face of the cover so a good finish is required. You can see I am facing it in reverse to prevent any bits of swarf getting under the tool and marking
the surface:
Turn it round use the 16mm diameter in a collet to hold the cover and cut the boss which goes into the cylinder and check it fits:
While it is mounted take the outside diameter to match the cylinder and sneak behind and to the top of the cover to avoid having to turn it round.
Finally drill through 4.5mm ( reamer starting size)
Can you see those horrible blow holes in the underside of the casting
No one will see them so time to put it to one side while admiring another casting:
It seems a waste to use that lovely piece of gunmetal when that scrappy piece of Aluminium will do just as well
Jo