John in NM
I can usually spot hand tool work, but then I'm aware of the distinctions. My wife is usually surprised at my extreme distaste for factory furniture, not seeing what I see. To me the finishes are obviously different, and the details of construction scream "factory" to me.

Now with high end custom furniture I often can't tell machine from hand work. At the level where aesthetics are chosen over quick construction, it becomes difficult to spot machine work - Just look at any of Bill Tindall's stuff in the gallery section here.

On a similar note, I once had a part I'd made with me at the day job (a telescope) and a grad student there who was in to CNC machines could not believe I'd made the part without a computer