Very very nice Stel! I have to make a half dozen too! That's the same design I was aiming for. It's always way easier to learn from what someone else did.
I had a different Operation Order in mind. I had thought I would start with round bar instead of flat stock and then drill on my rotary table on the mill.
Why did you make them round last? Was that mostly so you could hold them in your vise during the drilling and tapping?
Perhaps I am missing something important that I wouldn't have discovered till I'd ruined a few parts or hit a dead end.
1. I didn't have round stock
2. There's 16 holes, so that's 22.5 degrees per hole....that's a pain doing it on the rotary table. Dividing head, yes.
3. All that swarf from drilling, threading, and boring all those holes, going into your chuck on the RT. Then having to clean it up to fo the next ring.
4. Parting can sometimes dish the surface.
I think doing it my way was very straight forward and pretty easy. If I had a large enough chamfering cutter to do the center bore would have saved me a lot of time.
On the first ring, I:
-spot drilled
-then directly to a #7 drill bit
-power tapped
-chamfered.
That means I went around 4 times.
The second and third rings, I spot drilled with a 1/2" 118° spot drill to a depth of 0.078". This way I didn't need to chamfer as a final operation, therefore only going around 3 times.