On 2010-01-29, Andrew VK3BFA wrote:
On Jan 29, 2:06?pm, Ignoramus2532
wrote:
I bought a "test bar", which is a 10" or so long with MT3 end.

I inserted centers in the headstock and tailstock and mounted the bar
between those. Then I aligned tailstock with headstock, such that the
position of the indicator was the same at both ends.

What you have done is align the test bar between the 2 centres. This
will give you accuracy when your turning between centres, but anything
else, ie chuck work, is unknown. You also need to check the spindle
alignment, preferably first, then align the tailstock. As Robert says,
the (Rollie's Dad's Method) method is good, even if a bit hard to
comprehend at first reading.
(I still need to pull my finger out and correct said measured errors
in my humble 9x20...but need to shift so much stuff to be able to get
access to ALL of the headstock bolts that it aint happened. Yet. But
its on the list).

Guys, thanks. I loathe to adjust the headstock, because I think that I
will make things worse, not better. Why would headstock be misaligned
on this 43 year old lathe? At this point I just want to
measure bed straightness. Anyway, measuring is easy and fun, and is a
harmless activity, so I will just continue on this part. I have a
longer precision ground shaft, but it is not yet center drilled, and I
wanted to do so accurately.

i