How to deburr cross holes inside a bore?

Aside, I noticed in your drawing, the part shows two nylon tipped thumb screws directly opposite each other, presumably to grip a shaft to prevent rotation or sliding? If so, having the screws 180 degrees apart may not be the best configuration. 60 to 90 degrees apart is considered much better for such an application. This is because when the screws are directly opposite each other, there are the only two points of contact on the shaft, basically pushing against each other. When the screws are offset, they work together forcing the shaft against the wall of the bore giving three points of contact, and over a wider area where the shaft meets the bore. That's why the set-screws are offset not opposite on motor pulleys, gears etc.
Of course this may not apply if there are other factors to consider or be necessary, for light duty applications.

Thanks for the great suggestion Flustered.

With the prototype I went with four 90° cross holes just for the "feel". These are thumbscrews, having the left hand turn left and the right hand turn right to tighten seems to come naturally, likewise to release. Having four screws has so far proven to be more than adequate from a holding standpoint. That said, I'm drilling and tapping with a spin indexer so any number of holes is easily possible.
 
I'd be curious to hear how the Noga ends up working on that curved surface of the inner bore. Seems it would just deburr in two locations, not the entire hole perimeter?

I like the suggestion to fill the bore (or the tapped holes) with sacrificial material prior to the cross-operation. Those are the gems we get from those with lots of experience.
 
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I'd be curious to hear how the Noga ends up working on that curved surface of the inner bore. Seems it would just deburr in two locations, not the entire hole perimeter?

I like the suggestion to fill the bore (or the tapped holes) with sacrificial material prior to the cross-operation. Those are the gems we get from those with lots of experience.
You and I both :D . From what I read it's designed to deburr holes drilled in pipe, we shall see. I know that using a countersink on the outside for example, will make an elliptical-looking recess; as long as the countersink is done deep enough to touch the radial hole edges, it works functionally. Maybe that's the same with this tool, it may need a slightly deeper deburr to touch the axial hole edge.
 
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