Cam bodies - machining the square sockets

Unless I screw up badly, this should be the last operation on the cam bodies. I'm planning on machining sockets that are 10mm across flats ie will accept the same chuck keys used by the 3 and 4 jaw chucks. 

Looking at the (male) keys themselves, there's a half decent radius on the edges, so I can machine the cavities with a sensible sized end mill, namely a 3mm diameter. I'll also want to chamfer the edges of the sockets and the ODs of the bodies.

Rather than plunge / ramp a 3mm end mill into the steel, I'll start off with an 8mm hole, down to the final depth of 7mm. Then rough and finish the square cavity.

I have some nice 8mm carbide end mills that can plunge cut. So off we go:

And the clearing / finishing with 3mm end mill:

Good. That went well.

Finish with the chamfer:

Loos good.

And it even fits.

Nice surface finish.

All done.

The chuck key doesn't sit as far in as on the std part but I haven't much meat left over for the retainer screw. It's possible I could have located the groove further inboard but here we are. A 7mm socket should be more than adequate surely.

So now I need to give them a bit of a polish, harden and temper them, then remove any oxidisation. Then I can move on to finishing off the main body and doing the final finish machining with it it in place on the spindle nose.