Removing the ram and playing with a mic, I get 1.622
diameter everywhere I measured it. I haven't measured
the bore yet.

OK, playing with my new telescoping HF bore gages
I get the following:

Inches ===== Measurement plane =====
in from Horiz. Vert., Vert.,
end unclamped clamped
------ ------ ------ ------
0 1.626 1.628 1.625
1 1.626 1.625 1.624
2 1.625 1.625 1.623
3* 1.623 1.623 1.622
4 1.623 1.622 1.622
*- End of the clamp slit.

Some of them clamp via a slit alonside the
casting, [...] What kind of setup does this
Hendy have?
The slit type, not the two-piece type.

If the bore really *is* bell-mouthed

Numbers pretty much say it is.

I think it would be informative to figure out
how those bores are formed in the first place.

Took another look at the assembly, and there is a
hole on the bottom side of the bell end where the
handle attaches. A blind hole. A spanner hole.
Ten seconds later, the entire handwheel and end
bell assemble is loose in my hands, and I'm looking
through a large bore, straight through the
tailstock. _Much_ better! Now I can go way up with
my boring bar ability. The only possible concern
here is the threads for the end bell are directly
in the tailstock bore, so I'd have to stop whatever
process I use short of mangling those threads.

I wonder if a reamer would provide an accurate
enough hole - would it follow the existing hole
axis close enough, and cut to size even though
the existing hole is bell-mouthed?

Enco has an adjustable reamer that goes up to
1-13/16ths for $35. Since I don't have to worry
about end-bell clearance, an adjustable would work,
and it looks like the majority of hand and chucking
reamers stop at 1-1/2. But I would expect boring
would give me a more accurate hole should the wear
not be even front-to-back or top-to-bottom, whereas
the reamer would follow the hole as worn, yes?
--Glenn Lyford