Hi eKretz:
At the risk of seeming contrary here, how do you propose to get the nearly sharp corners in the pocket using the rotary table?
If the OP can tolerate radii in the corners, yes you could swing it out with a rotary table and a ball cutter, but if he cannot tolerate at least a 1/8" corner radius at each end of that pocket, the rotary table and a ball end mill will not get all the geometry.
This presumes the axis of the cutter is orthogonal to the axis of the pocket (as it would be if you surface milled it on a CNC)
As soon as you make the axis of any spinning cutter coaxial with the axis of the pocket you MUST make them concentric as well to get to the bottom of the pocket, and that means a tee slot cutter of maximum 1 1/4" diameter with a zero diameter shank unless you poke the shank through the bores before you insert the cutter.
As soon as you do that, you may not just stick the cutter out to the correct final diameter and turn on the mill...you'll break the cutter off as soon as it slams into the unmilled pocket.
So you would need to nibble it out bit by bit, growing the diameter by advancing the cutter a tiny bit each time so you can spin it and take a chip without snapping it off.
I do understand with the method you are describing that you never spin the cutter; you are using it like a shaper cutter and traversing from one pocket wall to the other...advancing the mill table to bring the cutter tip successively toward the surface you intend to machine as you swing out the arc using the rotary.
However, what your method neglects is what happens at the beginning of the stroke as the cutter needs to be forced into the workpiece and what happens at the end of the stroke as the cutter piles the chip into the bottom corner of the pocket.
If you have ever shaped a blind keyway on the lathe, you will recognize the problem: unless you've machined a relief groove or drilled a relief hole at the blind end of the keyway...with every successive stroke, the chip prevents you from getting as close to the bottom as you did with the prior stroke, and if you try to force it you eventually break the cutter.
So in theory, your approach can be made to broach out the OP's desired shape, but in practice, it sadly cannot, and when finishing the ends of the pockets (the inside faces of the ears, you cannot use a cutter other than a boring bar, with inserted tip run concentric to the bores and taking the whole of the face width in one pass.
You can sneak in with the smallest shank, largest diameter tee slot cutter you can rustle up to get some of it, but ultimately, you need a boring bar to catch the last bit of the inside corners of the pocket, and you NEED to poke the bar through the clevis bores.
Cheers
Marcus
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