Thanks for all the kind comments, now can you tell what this is yet?
Two discs were cut off my ever shrinking piece of 80mm dia cast iron bar by hand to approx 1/2" thick and are to become the eccentric straps. These were then poped into the lathe and faced off to give a finished thickness of 3/8".
I then did a quick bit of layout with a pencil to see roughly how much I could take off to get a flat reference face, this and the next few stages were all done with the discs held vertically in the mill vice and cut with a 1/2" endmill.
With the reference face established the discs were blued and marked out with the height gauge and the four extremities cut, you will notice I have left an 1/8" strip in the middle to allow for cutting and cleaning up the face.
The flat faces for the bolts were then machined and some of the waste removed just by eyeballing clear of the line. The holes were also drilled at this setting. In addition I formed a flat to screw an oil cup into, these can be seen on the original photo but are not on AM's drawings
The discs were then cut in half with a hacksaw and machined back to the line, the socket head screws are only there while there is more machining to be done.
The centres were marked and the strap mounted in the 4-jaw to bore the hole to 1 3/4".
They were then held by this hole on the rotary table to clean up the outside profile using a 1/4" FC-3 cutter
I then knocked up some filing buttons to round off the bolting lugs, quick tip when doing this the nut often works loose so give it a quick tap with a hammer which makes it slightly oval and it won't come loose again.
Add a couple of fitted bolts, nuts & locknuts and thats them done save for a bit of clean up before final assembly.
Any one want to guess what percentage of the original discs ended up as swarf? answeres in a day or two.
J