To hold the part machined cylinder while the end flanges were given their "teardrop" shape I used the CNC to make a simple fixture with two spigots that located into the cylinder and valve bores and tapped for a couple of M6 fixings. It was then just a cas eof screwing the cylinder to the jig and running a 3D adaptive to remove the waste and then a finishing 2D contour on each end.
Any excuse for a quick test fit
I also turned up the cylinder and valve end covers. This is the spigot that will locate the cylinder into the trunk guide being turned as a second op and held in the softjaws and the trunk guide being used to gauge the final diameter
Here are the four covers with all the lathe work complete. I also turned the two bronze glands as "tophat" shapes and drilled their two stud holes in each.
Over to the CNC the holes were drilled and tapped as required, the bronze glands screwed into place and the two machined as one to their final elliptical profile.
Well it would be nice to say it all went well but I did make a bit of a booboo profiling the first cylinder end. I thought I would be clever and draw the jig in F360 with the larger spigot centred on the X-Y axis as that is what I had used as the datum on the cylinder CAM. However I forgot that when going from design to manufacture (CAM) in F360 the part centres on the material by default so when it came to cut the profile the cylinder was 10mm to the left of where the cutter thought it was. As you will see instead of taking a 0.6mm cut off the left edge the cutter went in at the full 6mm width. Luckily it was on the side of the teardrop where the most metal needed removing and I was able to click the stop icon before I cut into metal that was meant to remain, it also kicked the jig off to the right so that had to be centred up again.
