Drill a tapered hole

build yourself a tapered reamer. shop built tapered reamers are pretty much standard operating procedure for woodwind instruments. basically a scraper blade let into a tapered wood plug. first you drill a series of straight holes, then you ream the taper.

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I was thinking of a Morse taper socket reamer, or a Jacobs taper, but then re-looked at the size and length you wanted... I agree, you will need to build (make? design?) your own tool.

Of course, the whole subject of making a scraper tool your self isn't exactly average person common knowledge.

Phil

If your metal working lathe has a suitable taper attachment, you can bore that conical hole. You might want to custom-build a boring bar from 2" OD pipe, but it's only wood, the boring bar won't take high stress.

If you have a metal working lathe, why not make one? An appropriate block of aluminum, brass, bronze, or steel would be adequate. Cut the taper you need, but small enough to install a slot for a single edge cutter. It can be as simple as a piece of file, saw blade, old plane iron, whatever. Set it deep enough to have a set screw to hold the blade. You don't need much of it other than the bevel out to cut, a bit like a plane iron. It will require cutting a straight sided lead hole to start in.

You never said what kind of taper you're looking for. Ridgid makes a pipe reamer that would cut wood and give you a taper, though it might be more than you want

Boring is certainly the way to go. Turning a taper reamer, or a taper drill bit, 10" long - even in wood - will take quite a bit of force.

John Martin