Started work on the rear cylinder cover. I managed to get three offcuts of 60mm BMS for 13 Euro which should be enough for the rear cylinder cover and the crosshead guide. Had to use the 4-jaw chuck as that is big enough to handle the material.

Machined one side.  The larger boss will fit in the crosshead guide. 

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I then drilled, reamed and tapped the boss 10 x 1 mm.  I used a 9mm slot drill so that I will get a relatively flat bottom.

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I then fitted the parting tool and went as deep as I could (why is this operation so nerve wracking?). The rest was done with a hacksaw.

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Replaced the 4-jaw chuck with the collet holder and finished off the other side of the cover.

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And how it looked on the cylinder block.

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Finished roughing out the bore and left it 1mm undersize. Used a series of drills up o 19mm and then bored to 21mm.

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I used an insert tool to rough out the OD of the guide and left it 1mm oversize.  I then left it a couple of days to 'rest' and then I finished it off by first boring the ID.

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Some more work on the crosshead guide.  The flange was trimmed from both sides.

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Drilled and tapped the last eight holes in the cylinder block for the rear cylinder cover and drilled the clearance holes in the cover.  I did not take any photos as I used exactly the same procedure I had used for the front cylinder cover.  This is  how it looks with the cover bolted to the cylinder.

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Next done were the clearance holes for the crosshead guide.  Used a V-block to hold the guide for drilling.

Initially, I was going to use the rear cylinder cover as a template for drilling, but then decided to use the DRO bolt hole function instead.

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The cover bolted to the crosshead guide to check for alignment.

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And finally, all the three pieces bolted together again to check for alignment.

Part 12 here  Part 14 here