Sanding roundover of through hole

[bmuir]

What's the best way to sand a roundover on a through hole? By hand? What power tool could I use?
Thanks for the help.

Bill

[LarryG]

When I just want to clean up the hole and ease the edge, I stick the corner of a sanding sponge into the hole and give it a few twists.

When I want an actual roundover, I chuck up a roundover bit with the desired radius in the router table. This presumes the hole diameter is large enough to accommodate the guide bearing on the bit, obviously.

[ironhat]

Larry has my vote. In a pinch I'll wrap a finger with sandpaper and twist it around but Uncle Arthur seems to be liking that less and less - ugh!

[LCHIEN]

you don't say what size hole and what radius roundover you want. And how close to really round you want it.
For large holes (e.g. 3/4" and larger) I'd use a roundover router bearing bit and make a few quick light passes.

For holes about 1/2" and smaller, I'd use a countersink bit to break the corners, at smaller sizes an ~45° countersink is as good as a roundover. For more rounded, you could then follow with some sandpaper by hand or even a dremel tool and some of those cone-shaped abrasive bits.